NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom

NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom.

Question 1.
What are the difficulties that you would face in the classification of animals if common fundamental features are not taken into account?
Solution:
There are millions of living organisms with a vast variety of shapes, sizes,s, and forms. They occur in a variety of habitats. It is difficult to identify and describe them at random, so they are classified into various categories. For identification and classification, different types of classification are required. There are fundamental features common to various individuals in relation to the arrangement of cells, body symmetry, nature of coelom, patterns of digestive, circulatory, or reproductive systems, etc. These features are used in the classification of animals.

Question 2.
If you are given a specimen, what are the steps that you would follow to classify it?
Solution:
Classification of specimen deals according to a systematic plan on the basis of their v similarities, differences and relationship.
We will take the following steps
(i) Level or grade of organisation:
There are different types of cell which are organised into functional units of progressively increasing complexity. Such as acellular, cellular, tissue, organ and organ system.
(ii) Pattern in organ system :
There are different organ system in which specific group of organs work together to do a specific function. Such as digestive organs in digestive system. Respiratory organs in respiratory system, etc. in animal body.
(iii) Symmetry:
In animals, 4-types of symmetry are seen. These are spherical, radial, bilateral, Asymmetrical species are classified according to symmetry.
(iv) Diploblastic and triploblastic organisation: According to number of germ layers which differentiate at the time of gastrulation in developing embryo. Species are classified as diploblastic i.e. two germ layer and Triploblastic i.e. three germ layers.
(v) Body cavity or coelom:
According to types of coelom, species are classified into acoelom, pseudocoelom and eucoelom animals.
(vi) Segmentation:
Species are classified according to segmentation. It is of three types i.e. pseudometamerism or false segmentation, internal and external segmentation.
(vii) Notochord:
On the basis of notochord, animals or species are divided into chordates and non-chordates.
We will follow the above steps in classification of animal, then fair idea of that animal can be derived.

Question 3.
How useful is the study of the nature of body cavity and coelom in the classification of animals?
Solution:
Coelom is the gap between gut and body wall. Coelom is the characteristic feature of complex or higher animals while lower animals like Platyhelminthes are acoelomate. The absence of coelom indicates that the animal is yet to develop a functional division of labour to carry out various activities. So the coelom characterises complexity of the animals and represents organic evolution.
There are three types of coelom
(i) Acoelom – It means absence of body cavity which is due to the failure of mesoderm to cavitate during embryogency, so there is no coelom, no peritonium. ex-porifera, colenterata, etc.
(ii) Pseudocoelom — It means presence of coelom that develops from the blastocoel but not lined by mesoderm, ex-nematodes, etc.
(iii) Eucoelom – It means hue coelom, which is lined by mesoderm resulting in tube within -tube design.
ex- higher invertebrates, chordates, etc.

Question 4.
Distinguish between intracellular and extracellular digestion?
Solution:

  1. Intracellular digestion takes place inside the cells by cellular enzymes, which are secreted by the surrounding cytoplasm into the food vacuole and the digestive products are then diffused in cytoplasm.
  2. It mainly occurs in unicellular organism and also is a less efficient method.
  3. Extracellular digestion occurs with the help of digestive enzymes poured into gastrovascular cavity by secretory cells and then the digestive products are diffused across the intestinal wall into various parts of the body.
  4. It mainly occurs in multicellular organisms and is more efficient.

Question 5.
What is the difference between direct and indirect development?
Solution:
In oviparous animals, the newly hatched young may resemble the adult. Such a development is called direct development. In some cases, the young hatched from eggs do not resemble the adult. These young are called larvae, nymphs, or naiad. They lead an independent life for some period and finally undergo important change to become adults. These changes from larvae to adults are called metamorphosis and such a development is called indirect development.

Question 6.
What are the peculiar features that you find in parasitic Platyhelminthes?
Solution:
Members of Platyhelminthes possess the following characteristics.

  • These are mostly endoparasites of animals including human.
  • Hook and suckers are present for attachment to host body.
  • They absorb nutrient from the host directly through their body surface.
  • These are free-living, parasitic forms. Tissue, organ, grade of body organization is seen.
  • The digestive tract is incomplete or absent.
  • Respiration is anaerobic.
  • Reproductive system of parasitic forms is highly developed with enormous power of reproduction.
  • Well defined excretory organs such as flame cells are present.

Question 7.
What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?
Solution:
The phylum Arthropoda constitutes the largest group of animals which include many economically important insects. Over two-thirds of all named species on earth are arthropods. They have an organ-system level of, body organization. They are bilaterally symmetrical, triploblastic, segmented, and acoelomate animals. The body of arthropods is covered by a chitinous cuticle which forms the exoskeleton. The body segments are fused to form the head, thorax, and abdomen. They have jointed appendages. The appendages are variously modified to form antennae, mouthparts, pincers, or walking legs.

The digestive system is complete. Respiratory organs are gills, book-gills, book lungs, or tracheal systems. The circulatory system is open type. The nervous system is almost similar to that of the annelids. Sensory organs include antennae for perceiving odor, receptors for taste, eyes, statocysts or balance organs, and sound receptors. Excretion takes place through green glands or malpighian tubules. They are mostly dioecious, Reproduction is sexual. Fertilization is usually internal. They are mostly oviparous. Development may be direct or indirect, passing through many larval stages. The process of transformation of a larva into an adult is called metamorphosis.

Question 8.
Water vascular system is the characteristic of which group of the following:
(a) Porifera
(b) Ctenophora
(c) Echinodermata
(d) Chordata
Solution:
Echinodermata – Its vascular system with tube feet helps in locomotion. A perforated plate , madreporite, permits entry of water into ambulacral system which also help in food and gas transport system.

Question 9.
“All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.
Solution:
The members of subphylum Vertebrata possess notochord during the embryonic period, which is replaced by a cartilaginous or bony vertebral column in the adult. Thus, all vertebrates are chordates but all chordates are not vertebrates. Besides the three basic chordate characters, vertebrates have a ventral muscular heart with two, three, or four chambers, kidneys for excretion and osmoregulation, and paired appendages which may be fins or limbs.

Question 10.
How important is the presence of an air bladder in Pisces?
Solution:
The class Osteichthyes possesses Air bladder. It helps the organism in regulating buoyancy. If the air bladder were absent the animal had to swim constantly to avoid sinking.

Question 11.
What are the modifications that are observed in birds that help them fly?
Solution:
The birds are adopted for flying by reducing the weight and other modifications which are as follows :

  • The forelimb modified into wings to assist in flight.
  • Left ovary absent or reduced
  • Presence of pneumatic or hollow bones for making a lightweight skeleton.
  • The aerodynamic body helps in flying.
  • Excretion of urine and faeces occurs through single opening.

Question 12.
Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
Solution:
Normally the number of eggs produced by oviparous is greater than the number of young ones by viviparous. The development of young ones is oviparous takes place outside the mother whereas in the viviparous the development of the embryo takes place inside the uterus of the mother hence a viviparous mother can have very less number of embryos at a time in her uterus. Whereas oviparous mothers have no need to feed their young ones (embryos) until hatched. Hence, largest in number.

Question 13.
13. Segmentation in the body is first observed in which of the following:
(a) Platyhelminthes
(b) Aschelminthes
(c) Annelida
(d) Arthropoda
Solution:
(c) Annelida.

Question 14.
Match the following:
(a) Operculum      (i) Ctenophora
(b) Parapodia       (ii) Mollusca
(c) Scales          (iii) Porifera
(d) Comb plates    (iv) Reptilia
(e) Radula          (v) Annelida
(f) Hair            (vi) Cyclostomata and Chondrichthyes
(g) Choanocytes  (vii) Mammalia
(h) Gill slits      (viii) Osteichthyes
Solution:
(a) Operculum            (viii) Porifera
(b) Parapodia            (v) Annelida
(c) Scales               (iv) Reptilia
(d) Comb Plates    (i) Ctenophora
(e) Radula               (ii) Mollusca
(f) Hair                 (vii) Mammalia
(g) Choanocytes    (iii) Porifera
(h) Gill slits           (v) Cyclostomata and Chondrichthys

Question 15.
Prepare a list of some animals that are found
parasitic on human beings.
Solution:

  • Taenia (Tapeworm)
  • Fasciola (liver fluke)
  • Planaria
  • Echinococcus
  • Pheretima (Earthworm)
  • Hirudinaria (leech)

VERY SHORT ANSWER QUESTIONS

Question 1.
What is common name of Euspongia ?
Solution:
Bath sponge

Question 2.
Name the class which is characterised by pneumatic bones.
Solution:
Aves

Question 3.
Give the characteristic feature of Echinodermata.
Solution:
Water vascular system

Question 4.
Name the phyla which shows metamerism.
Solution:
Annelida, Arthropoda and Chordata.

Question 5.
Name two animal groups with incomplete digestive tract.
Solution:
Cnidariaandplatyhelminthes.

Question 6.
Name a fresh water sponge and coelenterate.
Solution:
Spongilla and Hydra

Question 7.
What is radula ?
Solution:
Rasping organ of molluscs.

Question 8.
Name two characteristic organs of chordates.
Solution:
Notochord and gill slits.

Question 9.
To which phyla Balanoglossus belong ?
Solution:
Hemichordata

Question 10.
Name two flightless birds.
Solution:
Ostrich, Kiwi

Question 11.
Give one example each of ectothermal and endothermal animals.
Solution:
Reptiles, mammals.

Question 12.
Give one example of cephalochordata.
Solution:
Branchiostoma (Amphioxus)

Question 13.
Why do lampreys and snakes lack girdles ?
Solution:
Due to lack of limbs.

Question 14.
What is the difference between epidermis of invertebrates and vertebrates ?
Solution:
Epidermis is a stratified epithelium in vertebrates and a simple epithelium in invertebrates.

Question 15.
Mention modification of coelom in echinoderms.
Solution:
A part of the echinoderm coelom is modified into a water-vascular system for help in locomotion.

Question 16.
What are setae ?
Solution:
Locomotive organs of phylum annelida.

Question 17.
What are endothermic animals ?
Solution:
Endothermic animals (birds and mammals) generate most of their body heat by metabolism.

Question 18.
Why is the Ornithorhynchus considered an 3 exceptional mammal ?
Solution:
Ornithorhynchus, though a mammal, lays egg and has a cloacal aperture.

SHORT ANSWER QUESTIONS

Question 1.
What are pneumatic bones ? Where do you find them?
Solution:
Bones having air spaces in them are called pneumatic bones. Birds have such types of bones to make body light for flying.

Question 2.
How do earthworm and leech differ with regard to their coelom ?
Solution:
Coelom is spacious in earthworm and greatly reduced in leech by formation of botryoidal tissue in it.

Question 3.
Cite unique features of nematodes.
Solution:
Syncytial epidermis, pseudocoel, non-muscular intestine and body wall musculature of longitudinal fibres only.

Question 4.
What is marsupium ?
Solution:
Marsupium is pouch on the females belly for rearing the young one in metatherian mammals. e.g. Kangaroo.

Question 5.
Why is coelentron called gastrovascular cavity ?
Solution:
It is a cavity in which both digestion and circulation occur.

Question 6.
What is the fate of notochord in higher chordate ?
Solution:
Notochord is replaced by vertebral column partly or fully in chordates.

Question 7.
State the two types of fishes. Give their examples.
Solution:
The two types of fishes are
(1) Chrondrichthyes example Trygon, electric ray
(2) Osteichthyes example Rohu, Sea horse

Question 8.
What is metamerism?
Solution:
It is a phenomenen found in organisms like earth worm that they have their bodies segmented and this parttem is called metameric segmentation.

Question 9.
Why are Urochordates called Tunicata?
Solution:
As the adult bodies of Urochordata is covered by a tunic like cover to these are called Tunicata.

Question 10.
Give an example of an organism showing.
(1) Radial symmetry
(2) Bilateral symmetry
Solution:
Radial symmetry: Star fish Bilateral symmetry: Octopus, men.

LONG ANSWER QUESTIONS

Question 1.
(i) What are different symmetry that exists in animal kingdom.
(ii) Distinguish between diploblastic and triploblastic
Solution:
(a) Asymmetrical symmetry
I. In many animals the body can not be divided in two equal halves on any plane.
II. Ex. Amoeba being irregular in shape, some sponges with various branching. Gastropod molluscs (snails, conch) have no symmetry due to torsion in embryonic stage.
(b) Radial symmetry
I. Any plane passing through a central axis of the body divides the organism into two identical halves.
II. Examples are Coelentrates, ctenophores and echinoderms.
(c) Bilateral symmetry
I. In most animals body can be divided into two equal halves on only one plane, hence body has left and right sides front and rear (back) sides; anterior and posterior ends; dorsal and ventral sides.
II. Their advance symmetry and such animals are most mobile.
Diploblastic animals: Animals in which cells are arranged in two embryonic layers, an external ectoderm and internal endoderm are called diploblastic animals.
Triploblastic animals: Animals in which developing embryo has the third germinal layers, mesoderm, in between the ectoderm and endoderm are called triploblastic animals.

Question 2.
Describe economic importance of the largest phylum.
Solution:
The largest phylum is Arhtropoda and its economic importance is as follows:

  • They are major agents for cross pollination. Insects, like butterflies and honey bee facilitate cross pollination.
  • Honey is an important food for human.
  • Many crustaceans, like lobsters and prawns are art of cuisine around the world.
  • The red dye cochineal, produced from a Central American species of insect, was economically important to the Aztecs and Mayans.
  • The blood of horseshoe crabs a clotting agent Limulus Amebocyte Lysate which is now used to test that antibiotics and kidney machines are free of dangerous bacteria, and to detect spinal meningitis and some cancers.
  • Maggots of housefly are used to treat those wounds which take time to heal because of absence of blood supply.
  • The relative simplicity of the arthropods ’ body plan, allowing them to move on a variety of surfaces both on land and in water, have made them useful as models for robotics.
  • They are carriers of many human parasite causing diseases like malaria, filaria and sleeping sickness.
  • Cockroaches are one of the major nuisance as they contaminate food in kitchens.
  • Termites are major causes of playing havoc with wooden furnitures.
  • Scorpions are known for their deadly sting, which can kill human and livestock.

Question 3.
What are the peculiar characters of Aschelminthes?
Solution:
(i) The body of aschelminthes is circular in cross-section, hence named round worms.
(ii) They may be free living, a quatic and terrestrial or parasitic in plants and animals.
(iii) They have organ-system level of body organisation.
(iv) They are bilaterally symmetrical, triploblastic andpseudocoelomate.
(v) Alimentary canal is complete with well developed muscular pharynx.
(vi) An excretory tube removes body waste from the body cavity through the excretory pore.
(vii) Sexes are separate (dioecious), i.e., males and females are distinct. Often females are longer than males.
(viii) Fertilisation is internal and development may be direct or indirect.
(ix) Examples. Ascaris (Round worm), Wuchereria (Filaria worm), Ancylostoma (Hookworm).

We hope the NCERT Solutions for Class 11 Biology at Work Chapter 4 Animal Kingdom, help you. If you have any query regarding NCERT Solutions for Class 11 Biology at Work Chapter 4 Animal Kingdom, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants

NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants.

Question 1.
What is meant by modification of root? What type of modification of root is found in the:
(a) Banyan tree
(b) Turnip
(c) Mangrove trees.
Solution:
Root in some plants change their shape and structure and become modified to perform functions other than absorption and conduction of water and minerals. This change is called the modification of root.
(a) Banyan Tree has roots called prop roots which are hanging structures that help in support.
(b) Turnip has tap roots which get swollen and store food.
(c) Mangrove trees are found in a marshy area. The roots get modified into pneumatic structures providing extra passage to allow additional oxygen to the plant.

Question 2.
Justify the following statements on the basis of external features:
1. Underground parts of a plant are not always roots.
2. Flower is a modified shoot.
Solution:
1. It is true that roots develop below the ground but there are exceptions. Potato is one such example. Here, in this case, the stem gets modified into a ‘tuber’ like structure for the storage of reserve food material. These tubers develop and grow under the ground.
This can be proved by the following:

  • The potato bears scale leaves (Leaves are found only in the stems)
  • They contain buds in the regions called eyes.
  • They contain nodes. It is justified from the above statements that underground parts of a plant are not always roots.

2. The flower is considered to be a modified shoot (it was suggested by Goethe 1760) because the internodes in a flower are highly condensed and the appendages such as sepals, petals, stamens, and carpels are generally large in number.

Question 3.
How is a pinnately compound leaf different from
a palmately compound leaf?
Solution:
In pinnately compound leaf, a number of leaflets are present on rachis (e.g., neem) whereas in palmately compound leaf, leaflets are attached at a common point i. e., at the tip of petiole e g., silk cotton.
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 1

Question 4.
Explain with suitable examples the different types of phyllotaxy.
Solution:

  • In a pinnately compound leaf, a number of leaflets are present on a common axis. Example: Neem leaves.
  • In palmately compound leaf, a number of leaflets are attached at the common point.
    Example: Cotton leaves.

Question 5.
Define the following terms:

  1. Aestivation
  2. Placentation
  3. Actinomorphic
  4. Zygomorphic
  5. Superior ovary
  6. Perigynous flower
  7. Epipetalous stamen.

Solution:

  1. Aestivation: The arrangement of sepals or petals with respect to one another in the floral bud is called ‘aestivation’.
  2. Placentation: It is the arrangement of placentae in the ovary. It may be marginally axile, parietal, basal, free central, and superficial.
  3. When a flower can be divided into t\Vo equal radial halves by any radial plane passing through the center, it is said to be actinomorphic as in mustard, Datura, chili.
  4. When a flower can be divided into two similar halves only in one particular vertical plane, it is zygomorphic, as in pea, Gulmohar, beam, Cassia, etc.
  5. Superior ovary: In the hypogynous flower the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flowers is said to be superior e.g., mustard, china-rose, and brinjal.
  6. Perigynous flower: If gynoecium is situated in the center and other parts of the flower are located on the rim of the thalamus almost at the same level, it is called a perigynous flower.
  7. Epipetalous stamen: When stamens are attached to the petals, they are epipetalous as in brinjal or epiphyllous when attached to the perianth as in the. flower of the lily.

Question 6.
Differentiate between
(a) Racemose and cymose inflorescence
(b) Fibrous root and adventitious root
(c) Apocarpous and syncarpous ovary
Solution:
The main difference between racemose and cymose inflorescence are as following:
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 2
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 3

Question 7.
Draw the labelled diagram of the following:
(i) Gram seed
(ii) Y. S. of maize seed
Solution:
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 4

Question 8.
Describe modifications of the stem with suitable examples.
Solution:

The stem may not always be typically like what it is expected to be. They are modified to perform different functions, (fig. 5.2)
(1) For storage food: Underground stems of potato, ginger, turmeric, Samarkand, colocasia are modified to store food in them. They also act as organs of presentation to tide over conditions unfavorable for growth.

(2) Support: Stem tendrils, which develop from axillary buds, are slender and spirally coiled and help the plant to climb such as in gourds (cucumber, pumpkins, watermelon) and grapevines.

(3) Protection: Axillary buds of stems may also get modified into woody, straight and pointed thorns. Thoms is found in many plants which protect them from browsing animals such as Citrus, Bougainvillaea.

(4) For Photosynthesis: Some plants of arid regions modify their stems into flattened (Opuntia), or fleshy cylindrical (Euphorbia) structures. They contain chlorophyll and carry out photosynthesis.

(5) Spread Underground: Stems of some plants such as grass and strawberry, etc. spread to new niches, and when older parts die new plants are formed.

(6) Vegetative propagation: In plants like mint and jasmine a slender lateral branch arises from the base of the main axis and after growing aerially for some time arch downwards to touch the ground. A lateral branch with short internodes and each node bearing a rosette of leaves and a tuft of roots are found in aquatic plants like Pistia and Eichhomia. In banana, pineapple, and Chrysanthemum, the lateral branches originate from the basal and underground portion of the main stem, grow horizontally beneath the soil, and then come out obliquely upward giving rise to leafy shoots.NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 5

Question 9.
Take one flower each of the families Fabaceae and Solanaceae and write its semi-technical description. Also draw their floral diagram after studying them.
Solution:
Fabaceae: This family was earlier called Papilionoideae, a subfamily of family Leguminosae. It is distributed all over the world.
Example: Pisam sativum
Semi technical description of Pisum sativum ^ are as follows :
Vegetative characters :
Habit: An annual herb.
Root: Nodulated tap root.
Stem: Climber, leaflet tendrils
Leaves: Alternate, pinnately compound or
simple; leaf base, pulvinate, stipulate, venation reticulate.
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 6
Floral characters:
Inflorescence: Racemose
Flower: Bisexual, zygomorphic, complete,
irregular, hypogynous
Calyx: Sepal 5, gamosepalous, valvate aestivation.
Corolla: Petals 5, polypetalous, papilionaceous consisting of a posterior standard, two lateral wings, two anterior ones forming a keel. Thus, flower becomes zygomorphic, with descending imbricate aestivation i.e. vexillary aestivation.
Androecium: Stamen 10, diadelphous [1 + (9)], anther dithecous, introrse.
Gynoecium: Ovary superior, monocarpellary, unilocular with many ovules, marginal placentation.
Fruit: Legume
Seed: One to many, non-endospermic.
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 7
Economic importance
Many plants belonging to the family are sources of pulses (gram, arhar, sem, moong, soyabean, edible oil (soybean, groundnut); fibres (sun hemp); fodder (Sesbania, Trifolium), ornamentals (lupin, sweet pea); medicine (muliathi).
Solanaceae:
It is large family, commonly called as the potato family. It is widely distributed in tropics, subtropics and temperate ones. Example: Datura
Semi technical description of Solatium nigrum.
Vegetative characters:
Habit: Annual herb
Stem: Erect, cylindrical, hairy, slightly fistular. Leaves: Alternate, simple, petiolate, ovate with acute apex, venation reticulate.

Floral characters:
Inflorescence: Solitary, axillary
Flower: Ebracteate, actinomorphic, hypogynous
Calyx: Sepals 5, gamosepalous, persistent, valvate aestivation.
Corolla: Petals 5, gamopetalous, valvate aestivation
Androecium: Stamen 5, epipetalous Gynoecium : Bicarpellary, syncarpous, ovary superior, bilocular but four celled by formation of false septum, placenta swollen with many ovules.
Fruit: Spinous capsule with septifragal dehiscence.
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 8
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 9

Question 10.
Describe the various types of placentations found in flowering plants.
Solution:
The arrangement of ovules within the ovary is known as placentation. The placentation of different types namely, marginal, axile, parietal, basal, central, and free central. In marginal placentation, the placenta forms a ridge along with the central structure of the ovary and the ovules are borne on this ridge forming two rows, as in pea. When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile, as in china-rose, tomato, and lemon.

In parietal placentation, the ovules develop on the inner wall of the ovary or on the peripheral part. The ovary is one-chambered but it becomes two-chambered due to the formation of the false septum e.g. mustard and Argemone. When the ovules are borne on the central axis and septa are absent, as in Dianthus and Primrose; this type of placentation is called free central. In basal placentation, the placenta develops at the base of the ovary and a single ovule is attached to it, as in sunflower, marigold.

Question 11.
What is the flower? Describe the parts of a typical angiosperm flower.
Solution:
The placentation of flowering plants is the distribution of ovule-bearing cushions or placentae inside the ovary. It is of the following types.

  1. Marginal. A monocarpellary unilocular, ovary bears ovules longitudinally along the ventral suture in one or two alternate rows, e.g., Pea.
  2. Parietal. A syncarpous, unilocular ovary bears two or more placentae longitudinally along the wall, e.g., Fumaria, Viola. A false septum occurs between two parietal placentae in the Mustard. It makes the ovary falsely bilocular. In cucurbits, the three parietal placentae grow inwardly, meet in the centre and bend outwardly. The ovary becomes trilocular.
  3. Axile. A syncarpous bilocular to multilocular ovary bears ovules on the central axile column where the septa meet, e.g., China rose, Petunia, Asphodelus.
  4. Free central. Polycarpellary syncarpous but unilocular, ovary bears ovules around a central column which is not connected to the ovary wall.
  5. Basal. Unilocular ovary bears a single ovule from the basal region, e.g., Ranunculus, Sunflower.
  6. Apical. Unilocular ovary bears a single ovule from the apical region, e.g., Cannabis.
  7. Superficial. Ovules are borne along the inner surface of the ovary including the septa if present, e.g., Butomus (unilocular), Nymphaea (multilocular).

Question 12.
How do the various leaf modifications help plants?
Solution:

  • Tendrils: Leaves are converted into tendrils for climbing as in pear or into spines for defense as in cacti.
  • Bulb: The fleshy leaves of onion and garlic store food. In some plants such as Australian acacia, the leaves are small and short-lived.
  • The petioles these plants expand, become green, and synthesize food. Leaves of certain insectivorous plants such as pitcher plants, Venus flytrap are also modified leaves.

Question 13.
Define the term inflorescence. Explain the basis for the different types of inflorescence in flowering plants.
Solution:

  1. The arrangement and distribution of flowers on the floral axis are termed inflorescence.
  2. Depending on whether the apex gets converted into a flower or continues to grow, two major types of inflorescences are defined – racemose and cymose.
  3. In the racemose type of inflorescence, the main axis continues to grow, the flowers are borne laterally in acropetal succession, i. e., older flowers are at the base and younger flowers are at the top.
  4. In cymose type of inflorescence, the main axis terminates in a flower, hence is limited in growth.
  5. The flowers are borne in a basipetal order, i.e., younger flowers are near the base and older
    NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 10

Question 14.
Writethefloral formula of an actinomorphic, biserial, hypogynous flower with five united sepals, five free petals, five free stamens and two united carples with superior ovary and axile placenta tion.
Solution:
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 11

Question 15.
Describe the arrangement of floral members in relation to their insertion on the thalamus. Calyx, corolla, androecium, and gynoecium.
Solution:
The flower is the reproductive unit in the angioSperms. It is meant for sexual reproduction.
A typical flower has four different kinds of whorls. arranged successively on the swollen end of the stalk or pedicel, called thalamus or receptacle. These are calyx, corolla, androecium, and gynoecium. Calyx and corolla are accessory organs, while androecium and gynoecium are reproductive organs. In some flowers like lily, the calyx and corolla are not distinct and are termed as perianth. When a flower has both androecium and gynoecium, it is bisexual. A flower having either only stamens or only carpels is unisexual.

In symmetry, the flower may be actinomorphic (radial) or zygomorphic (bilateral). When a flower can be divided into two equal radial halves in any radial plane passing through the center, it is said to be actinomorphic e.g. mustard, datura, chili. When it can be divided into two similar halves only in one particular vertical plane, it is zygomorphic e.g., pea, Gulmohar, bean, cassia. A flower is asymmetric (irregular) if it cannot be divided into two similar halves by any vertical plane passing through the center as in canna.

A flower may be trimerous, tetramerous, or pentamerous when the floral appendages are in multiples of 3,4 or 5, respectively. Flowers with bracts (reduced leaf found at the base of the medical) are called bracteate and those without bracts, ebracteate. Based on the position of calyx, corolla, and androecium in respect of the ovary and thalamus, the flowers are described as: hypogynous; perigynous, and epigynous. In the hypogynous flower, the gynoecium occupies the highest position while the other parts are situated below it. The ovary in such flowers is said to be superior e.g., mustard, china-rose, and brinjal.

If gynoecium is situated in the center and other parts of the flower are located on the rim of the thalamus almost at the same level, it is called perigynous. The ovary here is said to be half inferior e.g., plum, rose, peach. In epigynous flowers, the margin of the thalamus grows upward enclosing the ovary completely and getting fused with it, the other parts of the flower arise above the ovary. Hence, the ovary is said to be ‘inferior’ as in flowers of guava and cucumber, and the ray florets of sunflower.

VERY SHORT ANSWER QUESTIONS

Question 1.
What does take over the function of photosynthesis in Opuntia?
Solution:
Strm

Question 2.
Which plant part has transformed into the following different modifications
(i) tendril of pumpkin
(ii) thorn of Citrus.
Solution:
Stem(Axillary buds)

Question 3.
Name a cultivated plant in which neither fruits nor seeds are formed.
Solution:
Sugarcane

Question 4.
What term is given to the arrangement of leaves on the stem?
Solution:
Phyllotaxy

Question 5.
Give one example where the epigynous type of flower is present.
Solution:
Sunflower

Question 6.
Which type of placentation is present in Lathyrusl.
Solution:
Marginal

Question 7.
Why are potato and sweet potato called tubers?
Solution:
Potato and sweet potato are called tubers because they are irregularly shaped swollen stem that stores plenty of food.

Question 8.
What is phyllode? Give one example of it.
Solution:
Petiole and rachis modified into leaf-like structures are called phyllodes. e.g., Parkinsonia Australian Acacia.

Question 9.
Distinguish between alternate and whorled phyllotaxy.
Solution:
In alternate phyllotaxy, only one leaf is borne at each node whereas in whorled phyllotaxy, more than two leaves are borne at each node.

Question 10.
What is a tetradynamous condition of stamens?
Solution:
Two out of six stamens are short while the remaining four are long.

Question 11.
Describe the corolla of the family – Fabaceae
Solution:
Corolla of family Fabaceae is papilionaceous i. e., consisting of posterior standard or vexillum, two lateral wings and anterior petals fused along margin to form keel or carina.

Question 12.
What is a floral diagram?
Solution:
Floral diagram is an illustration of the relative and number of parts in each of the sets of organs comprising a flower.

Question 13.
Give any two reasons to justify that the onion bulb is a modified stem.
Solution:
It bears a large number of fibrous adventitious roots at its base. It bears several fleshy sheathing leaf bases and a terminal bud.

Question 14.
What are the main characters of the family Brassicaceae?
Solution:
Tetramerous flowers, six stamens, bicarpellary gynoecium, siliqua type fruit.

Question 15.
Name the food-yielding plants of Liliaceae.
Solution:
Allium cepa, A. sativum and Asparagus racemosus.

Question 16.
What is meant by maturation zone?
Solution:
The part of the root which is most active in water absorption is called the maturation zone.

Question 17.
What type of function is performed by the fleshy leaves of onion and garlic?
Solution:
The function of fleshy leaves of onion and garlic is storage

SHORT ANSWER QUESTIONS

Question 1.
What is a fruit? Describe the parts of a fruit.
Solution:
The fruit is a characteristic feature of flowering plants. It is a mature or ripened ovary, developed after fertilisation.
The fruit consists of a wall or pericarp and seeds. The pericarp may be dry or fleshy. When pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp and the inner endocarp.
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 12

Question 2.
Distinguish between prop roots and stilt roots
Solution:
The main differences between prop roots and stilt roots are as following
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 13

Question 3.
What is pneumatophore? How do they help the plant? Name an example.
Solution:
Pneumatophores:

  • These are the roots that grow vertically upwards and come above the soil surface; they bear opening called pneumatophores, for the exchange of gases.
  • This feature is an adaptation for plants growing in marshy/swampy areas, where oxygen is deficient in the soil.
  • These roots help the plants to get oxygen from the air for respiration e.g., Rhizophora.

Question 4.
What is the function of the leaf?
Solution:
The leaf is a green, flattened outgrowth of the plant arising from the node of the stem and is specialized to perform the process of photosynthesis. Therefore, the leaf is also known as the kitchen or food factory of the plant.

Question 5.
What is the main function of the root system?
Solution:
The root, system generally grows beneath the ground into the soil, functions of the root system are as follows:

  • It provides great anchorage and support to the plant. Huge trees such as mango, redwood stand erect due to the root.
  • The root hair absorbs nutrients, water, and oxygen from the soil and conducts them to the upper parts of my plants.
  • some of the taproots are specially modified for the storage of carbohydrates and water.

Question 6.
What is the aleurone layer?
Solution:
The major part of the grain is occupied by large endosperm which is rich in starch. The endosperm has one to three-layered peripheral protein layer called the aleurone layer which separates the embryo with endosperm.

LONG ANSWER QUESTIONS

Question 1.
Describe the various parts of an angiosperm plant with a well labelled diagram.
Solution:
Parts of an angiosperm plant: The body of an angiosperm plant consists of the following parts:

  • root
  • stem
  • leaves
  • flowers
  • fruits
  • seeds

(i) Root: It is mostly underground and colourless. It is profusely branched. Its main function is to give support to the plant, fix the plant in the soil, and absorb water and food from the soil.

(ii) Stem: It is the aerial part. It bears fruit, leaves, branches, flowers, etc., and conducts water and minerals from the roots to the various parts of the plant body. The leaves on the stem arise from nodes. The region of the stem between two nodes is called the internode. Leaf axil is the angle formed by the base of the leaf and stem. At each leaf, axil is present a bud, which gives rise to a branch.

(iii) Leaf: These are green in colour. Leaves are termed food factories. The large portion of the leaf is termed as lamina while the stalk is called as petiole.

(iv) Flowers: These are variously formed and attractively coloured structures of the plant. They produce fruits and seeds.

(v) Fruits: The fruit is a characteristic feature of flowering plants. Generally, the fruit consists of a wall or pericarp and seeds. The pericarp may be dry or fleshy. When pericarp is thick and fleshy, it is differentiated into the outer epicarp, the middle mesocarp and the inner endocarp.

(vi) Seeds: The ovules after fertilisation, develop into seeds. A seed is made up of a seed coat and an embryo.
The embryo is made up of a radicle, an embryonal axis, and one (as in wheat, maize) or two cotyledons (as in gram and pea)
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 14

Question 2.
Mention the diagnostic characters of the family Fabaceae and write the floral formula
Solution:
Diagnostic characters of family Fabaceae are:

  1. Presence of nodulated roots.
  2. Inflorescence racemose.
  3. Perigynous ovary.
  4. Flower zygomorphic and papilionaceous.
  5. Calyx 5, gamosepalous.
  6. Corolla 5, petals unequal and differentiated into standard, 2 lateral wings and two smallest anterior petals (keel).
  7. Androecium commonly diadelphous (1+9 or 5 + 5) or monoadelphous (10 or 9)
  8. Gynoecium monocarpellary, ovary is unilocular with marginal placentation.
  9. Fruit legume.
    NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 15

Question 3.
Write five differences between a dicot seed and a monocot seed.
Solution:
The differences between dicot seeds and monocot seeds are:
NCERT Solutions for Class 11 Biology Chapter 5 Morphology of Flowering Plants 16

Question 4.
Describe placentation in flower:
Solution:
The arrangement of the placenta in the ovary of the flower is known as placentation. Its main function is to transfer nutrients from maternal tissue to the growing embryo.

  • Marginal placentation: It is found in the monocarpellary ovary. In this, the ovary is unilocular and ovules are arranged along the margin of the unilocular ovary. Ex- Pea, Clitoria, etc.
  • Axile placentation: It is found in bi or multicarpellary and multilocular ovary. Ovules are arranged along the central axis of placenta and the number of chambers corresponds to the number of carpels. Ex- Lemon, Tomato, Hibiscus, Cotton, etc.
  • Parietal placentation: It is found in bi or multicarpellary ovary but unilocular. Ovules are arranged along periphery or the inner walls of ovary and the number of placenta corresponds to the carpels. Ex – Cucurbita, Argemone, etc.
  • Free central placentation: It is found in multicarpellary syncarpous ovary. Ovules are borne along the central axis. Which is not connected with the ovary wall by the septum.
    Ex- Dianthus Rome primrose, etc.
  • Basal placentation: It is found in monocarpellary but unilocular. In this placentation, the placenta develops at the base of the ovary and a-single ovule is attached to it. Ex – Sunflower, etc.

We hope the NCERT Solutions for Class 11 Biology at Work Chapter 5 Morphology of Flowering Plants, help you. If you have any query regarding NCERT Solutions for Class 11 Biology at Work Chapter 5 Morphology of Flowering Plants, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom

NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom.

Question 1.
What is the basis of the classification of algae?
Solution:
Classification of Algae: The algae are divided into three main classes: Chlorophyceae, Phaeophyceae, and Rhodophyceae.

  1. Chlorophyceae: The members of Chlorophyceae are commonly called green algae.
  2. Phaeophyceae: The members of Phaeophyceae or brown algae, are found primarily in marine habitats.
  3. Rhodophyta is commonly called red algae. (See Table on the opposite page)

Question 2.
When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
Solution:
I. Liverwort – The main part of the body of liverwort is thalloid. Haploid gametes are produced from the male and female sex organs garnets fuses to form zygote. Zygote develops in the form of sporophytes. These sporophytes are further differentiated into foot, seta and capsule. As a result of reduction division many haploid spores are produced in capsule.
II. Moss – In the first stage in moss primary protonema develops into secondary ’ protonema. Both these stages are haploid. Zygote formed by the fusion of gametes further produce sporophytes.
III. Fern – Leaves of sporophyte bear sporangia in which spores are produced by reduction division in meiosis.
IV. Gymnosperm – In microsporophylls and megasporophylls that bear microsporangia and megasporangia respectively, reduction division occurs to produce microspores (pollen grains) and megaspore.
V. Angiosperm – Main part of the body is sporophytic and bears flowers. Reduction division takes place in anthers of stamen i.e. haploid pollen grains and in the ovary of pistil producing eggs.

Question 3.
Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.
Solution:

Archegonia is the female reproductive organ of

  1. Bryophytes
  2. Pteridophytes and
  3. Gymnosperms groups of plants.

The life cycle of gymnosperms: The gymnosperms are heterosporous, they produce haploid microspores and megaspores. The two kinds of spores are produced within sporangia that are borne oil sporophylls which are arranged spirally along an axis to form lax or compact strobili or cones.
The strobili bearing microsporophylls and microsporangia are called microsporangia or male strobili. The microspores develop into a male gametophytic generation which is highly reduced and is confined to only a limited number of cells. This reduced gametophyte is called pollen-grain. The development of pollen- grains takes place within the microsporangia.

The cones Rearing megasporophylls with ovules or megasporangia are called microsporangia or female strobili. The male or female cones or strobili may be borne on the same tree or on different trees. The megaspore mother cell is differentiated from one of the cells of the nucellus. The nucellus is protected by envelopes and the composite structure is called an ovule.

The ovules are borne on megasporophylls which may be clustered to form the female cones. The female cones are borne on the main plant body of the sporophyte. The megaspore mother cell divides meiotically to form four megaspores. One of the megaspores enclosed within the megasporangium (nucleus) develops into a multicellular female gametophyte that bears two or more archegonia or female sex organs. The multicellular female gametophytes are also retained within megasporangium.

Three groups of plant that bear archegonia are
1. Bryophyta,
2. Pteridophyta and
3. Gymnosperm.

  1. Life cycle of gymnosperms: The gymnosperms are heterosporous, they produce haploid microspores and megaspores.
  2. The two kinds of spores are produced within sporangia that are borne on sporophyll which are arranged spirally along an axis to form strobili or cones.
  3. The strobili bearing microsporophylls and microsporongia are called microsporangiate or male strobili.
  4. The microspores develop into a male gametophytic generation which is highly reduced, and confined to only limited number of cells. The reduced gametophyte is called pollen grain.
  5. The development of pollen grain takes place within microsporangia.
    The cones bearing megasporophylls with ovules or megasporangia are called macrosporangiate or female strobili.
  6. The male or female cones or strobili may be borne on the same tree or different trees. The megaspore mother cell is differentiated from one of the cells of the nucellus.
  7. The nucellus is protected by envelopes and the composite structure is called an ovule. The ovules are borne on megasporophylls which may be clustered to form the female cones.
  8. The females cones are borne on the main plant body of the sporophyte. The megaspore mother cell divides meiotically to form four megaspore.
  9. One of the megaspore enclosed within the megasporangium develops into a multicellular female gametophyte that bears 2 or more archegonia or female sex organs.
  10. The multicellular female gametophyte is also remaining within megasporangium.

Question 4.
Mention the ploidy of the following: protonemal cells of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a fern; gemma cell in Marchantia; Meristem cells of monocot, ovum of liverwort and zygote of a fern.
Solution:
Protonemal cells of a moss – Haploid (n) Primary endosperm nucleus in dicot – Triploid (3n)
Leaf cell of a moss – Haploid (n)
Prothallus cell of a fem – Haploid (n)
Gemma cell in Marchantia – Haploid (n) Meristem cells of monocot – Diploid (2n) Ovum of liverwort – Haploid (n)
Zygote of a fem – Diploid (2n)

Question 5.
Write a note on economic importance of algae and gymnosperms.
Solution:

  1. Algae like Chlorella, Gelidium (produce agar- agar) are used as food. Many algae like diatoms (used in manufacture of glass, polish, etc), algin (used in vulcanisation, artificial fibres, etc.), are used in industry.
  2. Nos toe, Anabaena, etc., are useful in increasing fertility of soil. Antibiotic chlorellin is extracted from Chlorella.
  3. Many algae have harmful effect also, for example, Microcystis, Chlrococcus, Oscillatoria cause water blooms and Cephaleuros species of algae are parasitic on tea leaves and cause harm to tea industry.
  4. v Alginic acid are extracted from the members Phaeophycea such as laminaria, Macrocystis and carrageenin is extracted from red algae chondris Crispos.

Economic importance of gymnosperms :

  1. Gymnosperms helps in checking soil erosion.
  2. Seeds of Pinns gerardiana, Gnetnm gnemon and Ginkgo biloba are eaten.
  3. Conifers like Pinus longifolia, Cedrus deodara, Picea, Tsngo, etc., produce soft wood. Bark of Tsugo yields tannins for making inks, seeds and bark of Cycas are used as poultica for wounds and sores.
  4. Ephedra, Gnetum, Taxus baccata, Cycles rumphii are used for medicinal purposes.

Question 6.
Both gymnosperms and angiosperms bear seeds, then why are they classified separately?
Solution:
Gymnosperms are ‘naked seeded’ plants because their seeds are not enclosed in fruit wall whereas angiosperm are ‘enclosed seeds’ as seeds (ovules) are found enclosed in the ovary wall.

Question 7.
What is heterospory? Briefly comment on its significance. Give two examples.
Solution:

  1. Genera like Selaginella and Salvinia which produce two kinds of spores macro and microspores are known as heterosporous.
  2. The megaspore and microspores germinate and give rise to female and male gametophytes, respectively.
  3. The female gametophytes in these plants are retained on the parent sporophyte for variable periods.
  4. The development of the zygotes into young embryo takes place within the female gametophytes.
  5. This event is considered as an important step in evolution leading to seed habit. Heterospory is considered as the first step towards seed habit. Selaginella and Marsilea, show seed habit.

Question 8.
Explain briefly
(i) Protonema
(ii) Antheridium
(iii) Archegonium
(iv) Diplontic
(v) Sporophyll
(vi) Isogamy
Solution:
(i) Protonema: The predominant stage of moss gametophyte which directly develops from spore is known as protonema.
(ii) Antheridium: The male sex organ in bryophytes, pteridophytes and gymnosperms is called antheridium. It bears male gamete.
(iii) Archegonium : It is the female sex organ found in bryophytes, pteridophytes and gymnosperms. It bears a female gamete.
(iv) Diplontic: In the life cycle of plants when their diploid stage is dominant for long time then this is called diplontic.
(v) Sporophyll: The sporophyte bears sporangia that are subtended by leaf-like appendages called sporophylls.
(vi) Isogamy: When the gametes involved in sexual reproduction are morphologically similar then this is called isogamy. These gametes are physiologically different.

Question 9.
Differentiate between the following:-
• Red algae and brown algae
• Liverworts and moss
• Homosporous and heterosporous pteridophyte
• Syngamy and triple fusion 
Solution:

Differences between red algae and brown algae are as follows
NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1
NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom 2

Question 10.
How would you distinguish monocots from dicots?
Solution:
Dicots are characterized by having two cotyledons in their seeds while the monocotyledons have only one.

Question 11.
Match the following content of column I with column II
Column I Column II
(a) Chlamydomonas (i) Moss
(b) Cycas (ii) Pteridophyta
(c) Selaginella (iii) Algae
(d) Sphagnum (iv) Gymnosperm
Solution:
(a) Chlamydomonas  (iii) Algae
(b) Cycas                    (iv) Gymnosperm
(c) Selaginella            (ii) Pteridophyta
(d) Sphagnum           (i) Moss

Question 12.
Describe the important characteristics of gymnosperms.
Solution:
The seed forming vascular plants which produce seeds but no fruits are called gymnosperms. General characters of gymnosperm are as follows:

  • Fertilization does not require water.
  • Leaves may be of two kinds: foliage leaves and scale leaves.
  • The ovules are orthotropus.
  • Most primitive seed-bearing plants.
  • Mostly these plants are evergreen.
  • Have no ovary wall, seeds are naked.
  • Exhibit polyembryony. Sexual reproduction oogamous type.
  • Large, tall and woody trees.

VERY SHORT ANSWER QUESTIONS

Question 1.
Which group of plants are commonly called “Amphibians of Plant Kingdom”?
Solution:
Bryophytes

Question 2.
Which pigment does provide red colour to red algae?
Solution:
Phycoerythrin.

Question 3.
Which alga does reproduce sexually by conjugation?
Solution:
Spiro gym

Question 4.
Name the organ that fixes the Plant body of Riccia to the soil.
Solution:
Hepaticopsida.

Question 5.
Which plant group is called vascular cryptograms?
Solution:
Pteridophytes.

Question 6.
Which plant is commonly called as walking fern?
Solution:
Adiantum

Question 7.
Which group of plants produces seed but not fruits?
Solution:
Gymnosperm.

Question 8.
Which part of ovule is haploid in gymnosperm?
Solution:
Endosperm

Question 9.
What is name of megasporophyll bearing ovules of angiosperm?
Solution:
Carpel.

Question 10.
Why do gymnosperms fail to produce fruits?
Solution:
Fruits are formed from ovaries. Since the gymnosperm ovules are not enclosed inside the ovaries, they do not produce fruit.

Question 11.
Why life cycle of angiosperm is called diplontic?
Solution:
Life cycle of angiosperm is called diplontic because the diploid (sporophytic) phase is more prominent and long-lived whereas the haploid (gametophytic) phase is short-lived.

Question 12.
Which algae is known as Rolling alga?
Solution:
Volvox

Question 13.
Which are the specialized structures in selaginella which bear adventitious roots?
Solution:
Rhizophores

Question 14.
What is the number of cells and nuclei present in the embryo sac of angiosperm?
Solution:
7 cells and 8 nuclei

Question 15.
Which plant is known as a living fossil?
Solution:
Cycas

SHORT ANSWER QUESTIONS

Question 1.
What are the salient features of pteridophyte?
Solution:
Pteridophytes are vascular cryptogams i.e., plants of this group possess vascular tissue (i. e., xylem, and phloem) for the conduction of water and minerals and for the translocation of foods. They are flowerless and seedless plants.
The general characters of pteridophytes are as following.
I. Primary root is short-lived. It is replaced by adventitious roots.
II. All vegetative parts possess vascular tissues. A cambium is altogether absent. In xylem trachea are absent and in phloem companion cells are absent.
III. Pteridophytes show origin and evolution of stele {i.e., vascular tissue, pericycle, and if present the pith).
IV. Pteridophytes are characterized by having only tracheids in their xylem and only sieve tube in their phloem.
V. The main plant body is the sporophyte (diploid), usually differentiated into true roots, true stems, and true leaves. A stem is usually an underground rhizome or an erect trunk as in tree ferns. Leaves are large (megaphyllous) and variously shaped.

Question 2.
What is the Alternation of Generation?
Solution:
gametophytic and sporophytic generations alternate in the life cycle, it is called the Alter-nation of generation. Or vice versa gametophyte produces gametes and their fusion product zygote or Oospore. Oospore produces sporophyte. The sporophyte produces spores. Spores germinate and produce gametophyte.

Question 3.
What are gemmae? Name two plants that produce gemmae.
Solution:
Gemmae are green, multicellular asexual buds, which develop in small receptacles, called gemmae cups, on the thallus.
The gemmae become detached from the parent thallus and germinate to form new individuals. e.g., Marchantia, Riccia.

Question 4.
Differentiate between cytotaxonomy and chemotaxonomy.
Solution:
Cytotaxonomy that is based on cytological information like chromosome number, structure, behaviour and chemotaxonomy that uses the chemical constituents of the plant to resolve confusions, are also used by taxonomists these days.

Question 5.
Differentiate between monocotyledon and dicotyledons.
Solution:
NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom 3

Question 6.
Mention four types of Placentation with suitable examples.
Solution:

  • Marginal placentation: Example members of the family fabaceae (Crotalaria)
  • Axile placentation: Example members of the family Malvaceae (Hibiscus)
  • Parietal placentation. Example: Cucumber.
  • Basal placentation Example: Sunflower.

Question 7.
What are the features of Gemmae found in bryophytes?
Solution:
Gemmae are the means of asexual reproduction found in many bryophytes (ex-Liverworts). They are one to many-celled, specially produced clonal plant fragments. They are green multicellular, asexual buds which develop in small receptacles called “gemma cups” located on the thalli. Gemmae become detached from the parent body and germinate to form a new individual

Question 8.
What is the basis of the classification of the phylogenetic system?
Solution:
It indicates evolutionary as well as the genetic relationship among organism, it is based on the fossil record, biochemical, anatomical, morphological, embryological, physiological, genetics, Karyotype, and other studies.

Question 9.
What are the main features of Anthocerotopsida?
Solution:
These are also known as hornworts because typical horn-like appearances are present of their sporophyte. These contain thalloid gametophyte, distinctly dorsiventral, rhizoids are present, Thalloid do not possess air chambers and scales. Each cell of thallus has a single large chloroplast with a pyrenoid.

LONG ANSWER QUESTIONS

Question 1.
Enumerate distinguishing characters of Bryophytes.
Solution:

  • Bryophytes are called “Amphibians of the plant kingdom” They grow in moist shady places. They require water for their sperms to swim towards eggs, hence the term ‘amphibians’.
  • The plant body is gametophyte so that it produces garnets.
  • The gametophyte is nonvascular so that xylem and phloem tissues are absent.
  • The gametophyte is thalloid in structure or it may be differentiated into stem-like, root-like and leaf-like organs.
  • Gametophyte reproduces sexually. The male sex organs are antheridia and the female sex organs are archegonia. Antheridia produce flagellated motile sperms. Archegonia produce female gamete or egg.
  • Fertilization results in the formation of diploid oospore. It produces diploid sporophyte Sporophyte reproduces asexually and produces haploid spores. They germinate and produce haploid gametophyte. The sporophyte is dependant on the gametophyte.
  • In the life cycle, there is an alternation of generation between haploid gametophyte and diploid sporophyte.
  • Bryophytes also show vegetative reproduction by fragmentation, gemmae formation etc.

Question 2.
Write short notes on the following :
(a) Peristomial teeth of moss
(b) Protonema of moss
(c) Archegonia of moss
Solution:
(a) Peristomal teeth are located just below the operculum. It helps in the dispersal of spores by the hygroscopic movement of its outer ring while the inner ring does not show the hygroscopic movements.
(b) Each spore produces a filamentous juvenile stage called protonema. Protonema has two types of branches, subterranean nongreen rhizoidal, and green Mediterranean branches. Buds develop on green prostrate branches which grow to form new moss plants.
(c) Female reproductive organ of moss is called archegonium.
NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom 4

 

Question 3.
Explain the general characters of the Gymnosperm plant body. (Tumkur 2008)
Solution:

  • Gymnosperm plant body is sporophyte.
  • Sporophyte consists of stem, root and leaves. Stem is unbranched in cycas. the stem bears crown of leaves at the tip.
  • The foliage leaves are pinnately compound in cycas and needle-like in conifers. Brown small non-photosynthetic leaves called scale leaves/cataphylls are present in cycas.
  • In cycas, the cataphylls are thickly covered with brown hairs called ramenta.
  • The foliage leaves are green. The pinnae are tough, leathery and has only midrib without veins.
  • Young leaves show circinate vernation.
  • The roots are inhabited by blue-green algae like Nostoc help the plant in nitrogen fixation
  • The sporophyte produces two types of spores so it is heterosporous.

Question 4.
Give a comparative account of gymnosperms and angiosperms.
Solution:
Comparison of gymnosperms and angiosperms
NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom 5

Question 5.
Describe major features of Plant kingdom.
Solution:
Features of Plant Kingdom:

  • Plants are autotrophic, except for some carnivorous, plants. They trap photo energy from sunlight and convert it to chemical energy through I photosynthesis. Because of this plants are the main channel for supplying energy in the food chain on earth.
  • Reproduction in plants can be by any of the following modes: Vegetative or Asexual, and Sexual Reproduction.
  • Plant cell is unique because of presence of cell wall and large vacuoles. Green parts of plant contain chlorophyll, which helps them in trapping the photo energy.
  • Sizes of plants can vary from microscopic to a very large tree. Plants are mainly divided into Algae, Bryophytes, Pteridophytes, Gymnosperms and Angiosperms.
  • Lower plants, like algae and bryophytes, have thalloid structures, while higher plants, like gymnosperms and angiosperms, have clearly defined roots and stems.
  • In higher plants root gives a means to anchor in the soil and helps the plant in taking minerals and water from the soil. Green leaves on the stem help them in photosynthesis.
  • Most of the plant growth as a result of photosynthesis. After photosynthesis, extra food is utilized to facilitate growth.
  • Usually in higher plants growth is unlimited and some taller trees can live a life of more than 1000 years.
  • Being the main carbon fixation agent, plants are very important for the whole ecology.
  • The whole food basket for humans is being filled by the plant kingdom. Even animal products, like milk and poultry, are indirect results of a plant’s carbon fixation.
  • Plants supply raw materials for a majority of economic activities. Wood for furniture and building materials comes from plants. The whole paper industry is dependent on the plant kingdom. Think of life if there was no paper and you may understand the larger impact on human civilization.
  • Angiosperms have special organs, called flowers, to bear sexual parts. Flowers are a helpful tool in facilitating variations and further evolution of the plant kingdom.

NCERT Solutions for Class 11 Biology Chapter 3 Plant Kingdom 6

We hope the NCERT Solutions for Class 11 Biology at Work Chapter 3 Plant Kingdom, help you. If you have any query regarding NCERT Solutions for Class 11 Biology at Work Chapter 3 Plant Kingdom, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants

NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants.

Question 1.
State the location and function of different types ofmeristems.
Solution:
NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 1

Question 2.
Cork cambium forms tissues that form the cork. Do you agree with this statement? Explain.
Solution:
Sooner or later, another meristematic tissue called cork cambium or phellogen develops, usually in the cortex region. Cork cambium is a couple of layers thick. It is made of narrow, thin-walled, and nearly rectangular cells. Cork cambium cuts off cells on both sides. The outer cells differentiate into cork or phellem while the inner cells differentiate into secondary cortex or phelloderm. The cork is impervious to water due to suberin deposition in the cell wall. The cells of the secondary cortex are parenchymatous. Phellogen, phellem, and phelloderm are collectively known as periderm.

Question 3.
Explain the process of secondary growth in the stems of woody angiosperms with the help of schematic diagrams. What is its significance?
Solution:
NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 2
showing secondary growth.
Secondary growth in dicot stem:

  1. It is a “permanent increase in thickness due to the activity of vascular cambium and cork cambium in stellar and extrasolar regions”. In dicot stem intra fascicular cambium is present.
  2. The cells of the medullary ray become meristematic and form interfascicular cambium.
  3. These two cambiums unite and make a complete cambial ring.
  4. The cells of it divide and produce new cells both on its outer and inner sides.
  5. The cells formed on the outer side differentiate into secondary phloem while the cells of the inner side form secondary xylem.
  6. The epidermis is replaced by a secondary protective tissue by an increase in the growth of the stem of the plant. It is made of phellogen (cork cambium).
  7. It arises from the peripheral cells of the cortex. The phellogen forms new cells on the outer side which make phellem (cork) and phelloderm on its inner side also.
  8. Significance: Secondary growth increases the girth or thickness of the plant.
  9. Annual rings of woody angiosperms are very distinct and thus helps in determining the age of the plant.

Question 4.
Draw illustrations to bring out the anatomical difference between
(a) Monocot root and dicot root
(b) Monocot stem and dicot stem
Solution:
NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 3
NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 4

Question 5.
Cut a transverse section of the young stem of a plant from your school garden and observe it under a microscope. How would you ascertain whether it is a monocot stem or a dicot stem? Give reasons.
Solution:
After observing the transverse section of the stem we can differentiate that stem is monocot or dicot on the basis of the following characters:
NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 5
Question 6.
The transverse section of a plant material shows the following anatomical features –

  1. the vascular bundles are conjoint, scattered, and surrounded by a sclerenchymatous bundle sheath,
  2. phloem parenchyma is absent What will you identify it as?

Solution:
The transverse section of a typical young monocotyledonous stem shows that

  1. The vascular bundles are conjoint, scattered, and surrounded by sclerenchymatous bundle sheaths
  2. Phloem parenchyma is absent, and water containing cavities are present within the vascular bundles.

Question 7.
Why xylem and phloem are called complex tissues?
Solution:
Xylem and phloem a composed of several types of cells and they work as a unit. Hence they are called complex tissues.

Question 8.
What is the stomatal apparatus? Explain the structure of stomata with a labelled diagram.
Solution:

  1. Several minute openings or stomata are found on the epidermis of all the green aerial parts of plants but are abundant on the lower surface on the leaves as they regulate the process of transpiration.
  2. A large number of stomata occur on the upper surface of leaves of aquatic plants.
  3. Each stomata is surrounded by two cells known as the guard cells. In the dicotyledons plants these are bean-shaped, but in sedges and grasses these are dumb-bell-shaped.
  4. The guard cell is living. Their outer walls are thin where as the inner ones surrounding the aperture are highly thickened.
  5. Due to this variation in the thickening, the guard cell may become turgid and flaccid, depending upon the supply of water in them, which makes the opening and closing of stomata possible.
  6. Some times a few neighbouring epidermal cells in the vicinity of guard cells become specialized in their shape and size and contents. These are known as subsidiary cells.
  7. The stomatal aperture, guard cells and the surrounding subsidiary cell are together called stomatal apparatus.

Question 9.
Name the three basic tissue systems in the flowering plants. Give the tissue names under each system.
Solution:
On the basis of their structure and location, there are three types of tissue systems. These are the

  1. Epidermal tissue system,
  2. The ground or fundamental tissue system and
  3. The vascular or conducting tissue system.

1. Epidermal tissue system The epidermal tissue system forms the outer-most covering of the whole plant body and comprises epidermal cells, stomata, and the epidermal appendages the trichomes, and hairs.
2. All tissues except epidermis and vascular bundles constitute the ground tissue. It consists of simple tissues such as parenchyma, collenchyma, and sclerenchyma.
3. The vascular system consists of complex tissues, the phloem, and the xylem. The xylem and phloem together constitute vascular bundles.

Question 10.
How is the plant anatomy useful to us?
Solution:
‘The study of plant anatomy is useful in many ways. First of all the study helps us understand the way a plant functions carrying out its routine activities like transpiration, photosynthesis, and growth and repair. Second, it helps botanists and agriculture scientists to understand the disease and cure for plants. Plants are important to maintain the ecological balance of the earth, so understanding plant anatomy is a way to understand the large system of the ecology on this planet.

Question 11.
What is periderm? How does periderm formation take place in the dicot stems?
Solution:
Phellogen, phellem, and phelloderm are collectively known as periderm. Phellogen develops, usually in the cortex region. Phellogen is a couple of layers thick. It is made of narrow, thin-walled, and nearly rectangular cells. Phellogen cuts off cells on both sides. The outer cells differentiate into cork or phellem while the inner cells differentiate into secondary cortex or phelloderm. The cork is impervious to water due to suberin deposition in the cell wall. The cells of the secondary cortex are parenchymatous.

Question 12.
Describe the internal structure of a dorsiventral leaf with the help of labelled diagrams.
Solution:
Dorsiventral (dicotyledonous) leaf: The vertical section of a dorsiventral leaf through the lamina shows three main parts, namely, epidermis, mesophyll, and vascular system.
Epidermis: The epidermis which covers both the upper surface (adaxial epidermis) and lower surface (abaxial epidermis) of the leaf has a conspicuous cuticle. The abaxial epidermis generally bears more stomata than the adaxial epidermis. The latter may even lack stomata.
Mesophyll:

  1. The tissue between the upper and the lower epidermis is called the mesophyll.
  2. It possesses chloroplasts and carries out photosynthesis, is made up of parenchyma.
  3. It has two types of cells – the palisade parenchyma and the spongy parenchyma.
  4. The adaxially placed palisade parenchyma is made up of elongated cells, which are arranged vertically and parallel to each other.
  5. The oval or round and loosely arranged spongy parenchyma is situated below the palisade cells and extends to the lower epidermis.
    NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 11
    6. There are numerous large spaces and air cavities between these cells.

Vascular system:

  • This includes vascular bundles, which can be seen in the veins and the midrib.
  • The size of the vascular bundles is dependent on the size of the veins.
  • The veins vary in thickness in the reticulate venation of the dicot leaves. The vascular bundles are surrounded by a layer of thick-walled bundle sheath cells.

VERY SHORT ANSWER QUESTIONS

Question 1.
Vascular bundles having cambium are known as.
Solution:
Open, Vascular bundle

Question 2.
Name the two types of sclerenchyma.
Solution:
Sclerenchyma fibers and stone cells.

Question 3.
From where do the secondary meristems originate?
Solution:
Permanent tissue.

Question 4.
What does make the root apical meristem subterminal?
Solution:
The presence of the root cap makes the root apical meristem subterminal.

Question 5.
Where are companion cells located in flowering plants? What are their functions?
Solution:
Companion cells are located in phloem cells of vascular tissues, they support the sieve tubes in water conduction.

Question 6.
What is the advantage of lignocellulose in the wall of the xylem?
Solution:
It provides rigidity, thickness, and resistance

Question 7.
A cross-section of a plant material shows the following features under the microscope: vascular bundles are radially arranged. These are found xylem strands showing exarch condition. What type of plant part of is this?
Solution:
Dicot root.

Question 8.
Based on position, classify various types of meristems
Solution:
Apical, intercalary and lateral meristems.

Question 9.
Name the various component cells of xylem. Which of them does not have a nucleus?
Solution:
Tracheids, vessels, xylem parenchyma andxylem fibres. Only xylem parenchyma have nucleus and living.

Question 10.
Give an example of a secondary meristem.
Solution:
Examples of secondary meristem are cork cambium and interfascicular cambium.

Question 11.
Name the tissue involved in linear and lateral growth in plants.
Solution:
Linear growth is caused by apical meristem and lateral growth is caused by lateral meristem.

Question 12.
Heartwood is more durable than springwood. Why?
Solution:
Heartwood is more durable than spring wood due to its little susceptibility to the attack of pathogens and insects.

Question 13.
Where these present:

  1. Hypodermis layer
  2. Mesophyll tissue
  3. Stomata
  4. Cambium

Solution:

  1. Hypodermis layer – is found in stems
  2. Mesophyll tissue – in leaves
  3. Stomata – lower epidermis in leaves
  4. CambiumIn vascular bundles which are open

SHORT ANSWER QUESTIONS

Question 1.
What are the differences between root hairs and stem hairs?
Solution:
The main difference between stem hairs and root hairs are :
.NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 9

Question 2.
Draw well labelled diagrams of the T.S. of dicotyledonous leaf.
Solution:
NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 10

Question 3.
Why is cambium considered to be a lateral meristem?
Solution:
Cambium is responsible for the increase in the thickness of stems and roots as a result of the addition of secondary tissues (secondary cortex, secondary phloem and secondary xylem). They are located at the lateral position so-known as lateral meristems.

Question 4.
Name the plant part in which the endodermis is absent. Give one basic difference between the endodermis and epidermis.
Solution:
The endodermis is absent in leaves. Cells of endodermis possess Casparian strips or bands in their radial and transverse walls which are not found in the epidermis.

Question 5.
What are Casparian strips?
Solution:
These are thickenings of lignin and suberin formed around the lateral walls of the endodermis to prevent plasmolysis.

Question 6.
Which tissue is most abundantly found in plants? Where all is it present in plants?
Solution:
The tissue most abundantly found in plants is parenchyma. It is found in pith, cortex, and in entire mesophyll of the leaves.

Question 7.
What is present in the phloem of leaves besides sieve elements and is it living or dead? How are these functional & used?
Solution:
Besides sieve elements, in phloem parenchyma, living cells are present. These store food other cells are phloem fibres that are dead and provide mechanical strength. These are also used in making ropes and coarse textiles.

LONG ANSWER QUESTIONS

Question 1.
Describe the structure and functions of xylem tissues in angiosperm plants.
Solution:

  • Xylem is a complex tissue. It forms a part of the vascular bundle.
  • It is mainly concerned with the conduction of water and minerals. It also provides mechanical support to the plant.
  • As a conducting strand, xylem forms a continuous channel through the roots, stem, leaves and other aerial parts.
  • It consists of four different types of cells—xylem vessels, trachieds, xylem fibres and xylem parenchyma.
  • Xylem vessels and tracheids are concerned with the conduction of water and minerals from roots to aerial parts of the plant.
  • Xylem fibres provide mechanical strength to the plant body. Xylem parenchyma are the only living components of xylem.
  • These are concerned with the storage of food and other vital functions.

Question 2.
What is collenchyma? Explain its structure and function in the plant body of a herbaceous angiosperm.
Solution:

  • The cells of collenchyma are somewhat elongated with cellulose thickening, found as longitudinal strips.
  • These are usually confined to the comers of the cells.
  • Collenchyma cells appear circular, oval or angular in the transverse section. Internally, each cell possesses a large 4 central vacuole, peripheral cytoplasm and a nucleus.
  • Collenchyma is usually found beneath the epidermis in stem, petiole and leaves of herbaceous dicot plants. It is usually absent in monocot stems and monocot roots.

Functions:

  • It provides tensile strength and rigidity to the plants due to thickening.
  • Chloroplasts containing collenchyma cells are responsible for photosynthesis.
  • Collenchyma also provides elasticity to the plant organs.
  • Collenchyma are alive and also stores food.

Question 3.
Explain sclerenchyma with a well labelled diagram.
Solution:
Sclerenchyma is a simple permanent tissue. It consists of two types of cells. They are sclerenchyma fibres and sclereids.
(a) Sclerenchyma fibres –

  • These are much elongated fibers with tapering ends.
  • On ipaturity, they lose their protoplasm and become dead. Their cell wall is made up of cellulose or lignin, or both.
  • Central cavity of the cell is greatly reduced due to the formation of secondary thickening. Sclerenchyma provides mechanical strength to the plants.
  • They help in conduction when present in the secondary xylem.

(b) Sclereids –

  • They develop from ordinary parenchyma cells by the deposition of lignin.
  • These cells are thick-walled and highly lignified and become dead on maturity.
  • They are broader as compared to fibers and their cell lumen is veiy narrow.
  • Sclereids protect the plant from environmental forces like a strong wind.
  • They provide mechanical strength and rigidity to the plant.
    NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 7

Question 4.
Describe the structure of a monocotyledonous leaf.
Solution:
Anatomy of Monocot/isobilateral leaf: The upper and lower surfaces are covered by a single-layered epidermis.

  • The upper epidermis has some cells larger than the others; such large cells are known as bulliform/motor cells.
  • Stomata are found on both upper and lower epidermal layers. The mesophyll is not differentiated into palisade and spongy parenchyma.
  • Mesophyll cells are isodiametric and are arranged compactly; they contain a number of chloroplasts. Since monocot leaves have parallel veins, a number of vascular bundles can be seen in a row in the section.
  • Each vascular bundle has sclerenchyma cells (caps) on its upper and lower edges.
  • The xylem is on the upper side and the phloem on the lower side. There is a parenchymatous bundle sheath, which often contains chloroplasts and performs the function of photosynthesis.
    NCERT Solutions for Class 11 Biology Chapter 6 Anatomy of Flowering Plants 8

Question 5.
Give two examples & salient features of
(1) Simple Tissue
(2) Complex Tissue
Solution:
(1) Simple Tissue:
(i) Parenchyma
(ii) Collenchyma
(2) Complex Tissue:
(i) Xylem
(ii) Phloem
(1) Simple Tissue:
(i) Parenchyma: These are living, thin-walled cells. It is used for storage of food, induction of substances, provides turgidity to softer parts of the plants
(ii) Collenchyma: These are longer than parenchyma. These are living mechanical tissue, it provides mechanical strength to organs and is present in peripheral position in plants to resist bending my the mind.
(2) Complex Tissue:
(i) Xylem: This is also called Hadrome, which is a water-conducting tissue. It is made up of cells like tracheids, xylem fibers, and xylem parenchyma only xylem parenchyma is living and all others are dead.
(ii) Phloem: This is also called Bast, which is a conducting tissue of food from leaves to all parts of the body. The parts of phloem are sieve elements, companion cells, phloem fibres, and phloem parenchyma. Phloem fibres are dead while parenchyma is living. Together these perform their function.

We hope the NCERT Solutions for Class 11 Biology at Work Chapter 6 Anatomy of Flowering Plants, help you. If you have any query regarding NCERT Solutions for Class 11 Biology at Work Chapter 6 Anatomy of Flowering Plants, drop a comment below and we will get back to you at the earliest.

NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification

NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification.

Question 1.
Discuss how classification systems have undergone several changes over a period of time?
Solution:
The classification was born instinctively out of a need to all organisms for our own use since the dawn of civilization. Aristotle was the earliest to attempt a more scientific basis for classification. He used simple morphological characteristics to classify plants into trees, herbs and shrubs. He also divided animals into Animals with red blood and those who do not have red blood. Linnaeus proposed a two-kingdom system of classification with Plantae and Animalia including plants and animals respectively.

The above system did not distinguish eukaryotes and prokaryotes, unicellular and multicellular, photosynthetic and non-photosynthetic organisms. A need was felt for including besides gross morphology, other characteristics like cell structure, nature of cell wall, mode of nutrition, habitat, method of reproduction, evolutionary relationships etc., Recently R.H. Whittaker proposed a five-kingdom classification to answer above the Five kingdoms are

  • Monera
  • Protista
  • Fungi
  • Plantae
  • Animalia.

Question 2.
State two economically important uses of
(a) heterotrophic bacteria
(b) archaebacteria
Solution:
(a) Heterotropic bacteria : These bacteria are natural scavengers. The souring of milk into lactic acid and alcohol to vinegar is brought about by some saprophytic bacteria, e.g., Lactic acid bacteria and acetic acid bacteria respectively.
A number of antibiotic are extracted from actinomycetes especially from the genus Streptomyces e.g. Streptomycin, Chloramphenicol, Oilorotetracycline, Erythromycin, Terramycin etc.
(b) Archaebacteria live as symbionts in the rumen of herbivorous animals.
Methanogens are present in the guts of several ruminant animals such as cows and buffaloes and they are responsible for the production of methane (biogas) from the dung of these animals.

Question 3.
What is the nature of the cell wall in diatoms?
Solution:
In diatoms, ail walls form two thin overlapping shells which fit together as in a soapbox. The walls are embedded with silica and thus the walls are indestructible. Thus diatoms have left behind a large amount of cell wall deposits in their habitat.

Question 4.
Find out what do the terms ‘algal bloom’ and ‘red tides’ signify?
Solution:
Algal bloom : When colour of water changes due to profuse growth of coloured phytoplankton, it is called algal bloom.
Red tides : Redness of the red sea is due to luxurient growth of Trichodesrium erythrium, a member of cynobacteria (blue green alage).

Question 5.
How are viroids different from viruses?
Solution:
Viroids are simpler than viruses, consisting of
a single RNA molecule that is not covered by protein capsid. The genetic material of viruses are surrounded by protein coat.

Question 6.
Describe briefly the four major groups of protozoa.
Solution:
The four major group of protozoa are flagellated protozoan, amoeboid protozoan, sporozoan, ciliated protozoan. The main characters of these group are as follows:
NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification 1

Question 7.
Plants are autotrophic. Can you think of some plants that are partly hetrotrophic?
Solution:
Bladderwort and venus fly trap are examples of insectivorous plants and Cuscuta is a parasite. These are plants which are partially heterotrophic.

Question 8.
What do the terms phycobiont and mycobiont signify?
Solution:
Lichens shows symbiotic association between algae and fungi. The fungal component of lichen is called mycobiont and the algal component is called phycobiont.

Question 9.
Give a comparative account of the classes of kingdom fungi under the following:
(a) Mode of nutrition
(b) Mode of reproduction
Solution:
Kingdom fungi has four classes, these are Phycomycetes, ascomycetes, basidiomycetes and Deuteromycetes. The comparison between these classes are as follows :
NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification 2

Question 10.
What are the characteristic features of Euglenoids?
Solution:
Euglenoids show the following characteristic features:

  • They store carbohydrates in the form of paramylon.
  • Since euglenoids are green and holophytic like other plants.
  • Few are non-green and saprophytic, some are holotropic.
  • They bear a red-pigmented eyespot and a gullet near the base of flagellum.
  • All the euglenoids have one or two flagella which help in swimming.
  • Absence of cell-wall but contain flexible pellicle made up of protein.
  • Freshwater, free-living found in ponds and ditches.

Question 11.
Give a brief account of viruses with respect to their structure and the nature of genetic material. Also, name four common viral diseases.
Solution:
Viruses have the following characteristics:
(i) All plant viruses have single-stranded RNA and all animal viruses have either single or double-stranded RNA or double-stranded DNA.
(ii) Protein vims also contain genetic material RNA or DNA. A vims is a nucleoprotein and the genetic material is infectious, These are obligate parasites, self replicating, non-cellular organisms.
(iii) Vimses are smaller than bacteria and their genetic material is surrounded by protein I coat called capsid. Capsid is made up of small subunits called capsomeres.
Four common viral diseases are :
(a) Cough and cold
(b) Mumps
(c) Influenza
(d) Smallpox

Question 12.
Organise a discussion is your class on the topic are viruses living or non-living?
Solution:
Vimses are link between living and non-living. They possess some living characters and some non-living characters. Crystallization is a non-living character but it can reproduce inside living body.
Actually vimses are metabolically inert when outside the host-cell. They reproduce using the metabolic machinery of the host cell.

VERY SHORT ANSWER QUESTIONS

Question 1.
Who wrote the books ‘Species Plantarum’ and ‘Systema Naturae?
Solution:
Carolus Linnaeus.

Question 2.
Name the two kingdoms of the living world proposed by Linnaeus.
Solution:
Plantae and Animalia

Question 3.
What are protists?
Solution:
Protists are unicellular, eukaryotic organisms.

Question 4.
Which organism was earlier placed in the plant as well as animal kingdoms and why?
Solution:
Euglena because it has locomotory organelle, flexible pellicle, contractile vacuole and reproduce by binary fission like animals and chloroplasts and pyrenoids like plants.

Question 5.
Name the 5 kingdoms of organisms in the order of their supposed evolution.
Solution:
Monera, Protista, Fungi, Animalia and Plantae.

Question 6.
Mention 2 traits in which fungi resemble animalia.
Solution:
Heterotrophy and glycogen as reserve food.

Question 7.
Define
(a) Plasmogamy
(b) Karyogamy
Solution:
(a) Plasmogamy – Fusion of protoplasms between two motile or non-motile gametes.
(b) Karyogamy – Fusion of two nuclei.

Question 8.
What is a retrovirus? Give an example
Solution:
Retrovirus is organisms that have RNA s as genetic material. For example HTV

Question 9.
Give two salient features of slime moulds.
Solution:
The two salient features of slime moulds are:

  1. These do not have a cell wall
  2. These have pseudopodia for movement

Question 10.
What is called the jokers of microbiology and why?
Solution:
Jokers of microbiology are mycoplasma as they have no cell wall and no definite shape.

Question 11.
Give the names of two diseases caused by Protozoans
Solution:
Two diseases caused by protozoans are
(1) Amoebiasis
(2) Malaria

SHORT ANSWER QUESTIONS

Question 1.
Cyanobacteria play a major role in our ecology. Discuss.
Solution:
Cyanobacteria, also known as ‘blue-green algae’ help in carbon fixation in a major way on the ocean surface.

They are helpful in nitrogen fixation in paddy fields leading to a better harvest. About 80% of photosynthesis on ocean surface is done by cyanobacteria. So, it can be said that they play a major role in our ecology.

Question 2.
What is the role of methanogens?
Solution:
Methanogens are type of bacteria which live in the gut of ruminating animals.

They assist those animals in digestion and the byproduct of that digestive process is methane.

More number of livestock population results in increased methane level in the environment leading to global warming. So, indirectly methanogens can be responsible for global warming.

Question 3.
What are lichens? What are the roles of lichen in water pollution ?
Solution:
Lichens are symbiotic associations i.e. mutually useful associations, between algae and fungi.

The algal component is known as phycobiont and fungal component as mycobiont, which are autotrophic and heterotrophic, respectively.

Algae prepare food for fungi and fungi provide shelter and absorb mineral nutrients and water for its partner. Lichens are very good pollution indicators as they do not grow in polluted areas.

Question 4.
On what factors is the 5 kingdom classification of Whittaker based?
Solution:
The five kingdom classification is based upon the following factors :
(i) Complexity of cell structure – Prokaryotes or Eukaryotes
(ii) Complexity of organisms body – Unicellular or Multicellular
(iii) Mode of obtaining nutrition – Autotrophs or Heterotrophs
(iv) Phylogenetic relationships

Question 5.
Give the technical terms used for the following:
(a) Remains of an organism of a former geological age.
(b) Science of classification of organisms.
(c) Evolutionary history of a group of organisms.
(d) Organisms which synthesize their own food, using chemical energy.
Solution:
(a) Fossils
(b) Taxonomy
(c) Evolution
(d) Autotrophs

Question 6.
What are the kinds (shapewise) bacteria found in nature. Name the pathogen with the disease caused
Solution:
NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification 3

 

Question 7.
Why is
(i) Basidiomycetes called club fungi?
(ii) Ascomycetes called sac fungi?
Solution:
(i) After sexual reproduction basidium is formed which form the shape a club and this chin these fungi are called Club Fungi.
(ii) In sexual reproduction ascospores are formed in a sac like asci and thus this fungi is called sac fungi.

LONG ANSWER QUESTIONS

Question 1.
Give an account of early work in taxonomy.
Solution:

  • Since the dawn of civilisation, there have been many attempts to classify living organisms.
  • It was done instinctively not using criteria that were scientific but borne out of a need to use organisms for our own use – for food, shelter and clothing.
  • Aristotle was the earliest to attempt a more scientific basis for classification. He used simple morphological characters to classify plants into trees, shrubs and herbs.
  • He also divided animals into two groups, those which had red blood and those that did not.
  • In Linnaeus’ time a Two Kingdom system of classification with Plantae and Animalia kingdoms was developed that included all plants and animals respectively.
  • Classification of organisms into plants and animals was easily done and was easy to understand, inspite, a large number of organisms did not fall into either category.
  • R.H. Whittaker (1969) proposed a Five Kingdom Classification.
  • The kingdoms defined by him were named Monera, Protista, Fungi, Plantae and Animalia.
  • The main criteria for classification used by him include cell structure, thallus organisation, mode of nutrition, reproduction and phylogenetic relationships.

Question 2.
Differentiate briefly characteristics of kingdom Plantae and Animalia.
Solution:

  • Kingdom Plantae includes all eukaryotic chlorophyll-containing organisms commonly called plants.
  • A few members are partially heterotrophic such as the insectivorous plants or parasites.
  • Bladderwort and Venus fly trap are examples of insectivorous plants and Cuscuta is a parasite.
  • The plant cells have an eukaryotic structure with prominent chloroplasts and cell wall mainly made of cellulose.
  • Plantae includes algae, bryophytes, pteridophytes, gymnosperms and angiosperms.
  • The animal kingdom is characterised by v heterotrophic eukaryotic organisms that are multicellular and their cells lack cell walls.
  • They directly or indirectly depend on plants for food. They digest their food in an internal cavity and store food reserves as glycogen or fat.
  • Their mode of nutrition is holozoic – by ingestion of food. They follow a definite growth pattern and grow into adults that have a definite shape and size.
  • Higher forms show elaborate sensory and neuromotor mechanism. Most of them are capable of locomotion.

Question 3.
Give the economic importance of diatoms. Diatoms are used
Solution:
(1) as a cleaning agent in tooth pastes and metal polishes.
(2) Adding to make sound proof rooms.
(3) In Alteration of sugar, alcohol and antibiotics
(4) as put in paints to ad the paint visibility at night
(5) as an insulating material in Refrigerators, fumances etc.

Question 4.
What are the distinguishing characters of kingdom fungi?
Solution:
The distinguishing characters of kingdom fungiare as follows :
(i) Fungi are non-vascular, non-seeded, non-flowering, eukaryotic achlorophyllous (nongreen), heterophic (heterophytic) spore bearing, thalloid, multicellular decomposers and mineralisers of organic wastes and help in recycling of matter in the biosphere.
(ii) In true fungi the plant body is thallus. It may be non-mycelial or mycelial.
a. Non mycelial: The non-mycelial forms are unicellular; however they may form a pseudomycelium by budding,
b. Mycelial: In mycelial form plant body is made up of thread like structures called hyphae. Hyphae are usually branched tube like structure bounded by a cell-wall of chitin. The hyphae may be septate (higher fungi) or aseptate (lower fungi).
Septate hyphae may be of 3 kinds, uninucleate (monokaryotic hyphae), with binucleate cells (dikaryotic hyphae) ormultinucleate. Some fungi are aseptate and known as coenocytic fungi, with hundreds of nuclei in continuous cytoplasmic mass.
(iii) The cell shows eukaryotic organization but lack chloroplast and Golgi bodies. The genetic material is DNA and mitosis is intracellular (karyochorisis).
(iv) Fungi lack chlorophyll, hence, they do not prepare food by photosynthesis. Thus they can grow everywhere, where organic material is available.
(v) Fungi are heterotrophs that acquire their nutrient by absorption. They store their food in the form of glycogen.
(vi) The primitive fungi have oogamous type of sexual reproduction where as most advanced ones do not have sexual reproduction.

Question 5.
Compare the main features of Monera with Protista.
Solution:
NCERT Solutions for Class 11 Biology Chapter 2 Biological Classification 4

 

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NCERT Solutions for Class 11 Biology Chapter 1 The Living World

NCERT Solutions for Class 11 Biology Chapter 1 The Living World

These Solutions are part of NCERT Solutions for Class 11 Biology. Here we have given NCERT Solutions for Class 11 Biology Chapter 1 The Living World.

Question 1.
Why are living organisms classified?
Solution:
Classification of living organisms grouped them in special categories, which is based on observable characters. It makes their study easy and convenient. For example, Mammals are those who possess mammary glands, the hair on the body, external pinnae, etc.

Question 2.
Why are classification systems changing every now and then?
Solution:
The classification system changes when more information becomes available about the organisms. Additional information are updated from time to time about different organisms at this stage there is a need arises to make changes in the classification system.

Question 3.
What different criteria would you choose to classify people that you meet often?
Solution:
Classification means the arrangement of organisms into groups on the basis of their affinities or relationships. The branch of biology that deals with the study of principles and procedures of biological classification are called taxonomy. Some fundamental elements of taxonomy are discussed below.

Nomenclature: It is the science of providing distinct and proper names to organisms. It is the determination of the correct name as per established universal practices and rules.

Classification: It deals with the mode of arranging organisms or group^ of organisms into categories according to a systematic plan or ah order. The categories used in the classification of animals are Class, Order, Family, Genus, and Species. Each category is a unit and is also called a taxon (PI. Taxa).

Identification: It is the determination of the correct name and place of an organism in a system of classification. It determines that the particular organism is similar to some other organism of known identity. This implies assigning an organism to a particular taxonomic group. Suppose there are three plants say x, y, z. AH represent different species. Another plant w resembles y. The recognition of the plant was identical to the already known plant y is its identification.
One of the important features of systematics is the naming of living organisms. The organisms have been given two types of names i.e

  • common or vernacular names
  • Scientific names.

Question 4.
What do we learn from the identification of individuals and populations?
Solution:
Identification of individuals and populations determines their exact place or position in the set plan of classification.

Question 5.
Given below is the scientific name of mango. Identify the correctly written name.
(a) Mangifera Indica
(b) Mangifera indica
Solution:
(b) Mangifera indica

Question 6.
Define a taxon. Give some examples of taxa at different hierarchical levels.
Solution:
“Taxon is a unit of classification or a rank or a level of hierarchy in system of classification. The following chart gives taxonomical categories showing a hierarchical arrangement in ascending order.

Kingdom
↑
phylum or Division
Class
↑
Order
↑
Family
↑
Genus
↑
Species

Question 7.
Can you identify the correct sequence of taxonomical categories?
(a) Species → Order → Phylum → Kingdom
(b) Genus → Species → Order → Kingdom
(c) Species → Genus → Order → Phylum
Solution:
(c) Species → Genus → Order → Phylum

Question 8.
Try to collect all the currently accepted meanings for the word ‘species’. Discuss with your teacher the meaning of species in the case of higher plants and animals on one hand and bacteria on the other hand.
Solution:

  1. Species is one of the basic units of biological classification. A species is often defined as a
    group of organisms capable of interbreeding aid in producing fertile offspring.
  2. Sometimes more precise or differing measures such as similarity of DNA, morphology o,^ecological niche are used to define the basis of species.
  3. In case of animals, the name of species is defined by the specific name or the specific epithet. For example, gray wolves belong to the species Canis lupus, golden Jackals to Cam’s aureus etc.
  4. Both of them belong to same genus Canis, but species name varies. But species name of plant is only called species epithet.
  5. The ‘specific name’ in botany is always the combination of genus name and species epithet such as saccharum in Acer saccharum (Sugar maple).
  6. But bacteria are grouped under four categories based on their shape – spherical, rod-shaped, comma and spiral shaped and species of bacteria is according to their shapes. Thus the meaning of species in higher organism and bacteria are different.

Question 9.
Define and understand the following terms:
(i) Phylum (ii) Class (iii) Family (iv) Order (v) Genus
Solution:
(i) Phylum: A phylum is a group of related classes having some common features, e.g., protozoa.
(ii) Class: A class is a group of related orders, for e.g., order Rodentia, Lagomorpha and Carnivora all having hair and milk glands are placed in class Mammalia.
(iii) Family: A family is a group of related genera. The genus Felis of cats and the genus Panthera of lion, tiger and leopard are placed in the family Felidal.
(iv) Order: An order is a group of related families. The family Felidae of cats and the »family Coridal of dogs are assigned to the order Carnivora. Cats and dogs have large canine teeth and are flesh-eaters.
(v) Genus: A genus is a group of species alike in the broad features of their organization but different in detail. As per the rules of binomial nomenclatures, a species can not be named without assigning it to a genus.
NCERT Solutions for Class 11 Biology Chapter 1 The Living World 1

Question 10.
How is key helpful in the identification and classification of organisms?
Solution:
Keys are contrasting pairs of characters (couplet), it represents the choice made between two opposite options. This results in acceptance of only one and rejection of the other. Each statement in the key is called a lead. Separate taxonomic keys are required for each taxonomic category such as family, genus, and species for identification purposes.

Question 11.
Illustrate the taxonomical hierarchy with suitable examples of a plant and an animal.
Solution: 
NCERT Solutions for Class 11 Biology Chapter 1 The Living World 2

VERY SHORT ANSWER QUESTIONS

Question 1.
Name the basic Unit of classification.
Solution:
Species.

Question 2.
Who introduced the hierarchy in taxonomy?
Solution:
Linnaeus

Question 3.
Who is the father of taxonomy?
Solution:
Carolus Linnaeus.

Question 4.
What is meant by cytotaxonomy?
Solution:
Classification based on chromosome number.

Question 5.
Who devised the binomial nomenclature?
Solution:
Carolus Linnaeus

Question 6.
What is a type specimen?
Solution:
Establishment of the name of the new species on the basis of the original specimen is called type specimen

Question 7.
In which language binomial nomenclature is written?
Solution:
Latin

Question 8.
What term is used to describe organisms without a well-developed nucleus?
Solution:
Prokaryote

Question 9.
Is inter-specific breeding possible?
Solution:
Yes, both.

Question 10.
What are DNA viruses / RNA viruses?
Solution:
Viruses that possess DNA as the genetic material are called DNA viruses.

Question 11.
What is speciation?
Solution:
Formation of a new species from an existing one by the appearance of mutation.

Question 12.
What are correlated characters?
Solution:
The common features the species have to qualify for inclusion in a genus are called correlated characters

Question 13.
Why classification of plants and animals is necessary?
Solution:
Classification divides millions of plant and animal species into convenient groups that make their study easier

Question 14.
What is cohort or order?
Solution:
The cohort is a unit of classification higher than the 6. family

Question 15.
Give an example of symbiotic bacteria.
Solution:
Rhizobium leguminosarum

Question 16.
Give botanical and zoological names of the following:
(1) Pea
(2) Wheat
(3) Man
(4) Potato
Solution:
(1) Pea → Pisumsatinum
(2) Wheat → Triticumaextivum
(3) Man → Homo sapiens
(4) Potato → Solanum tuberosum

SHORT ANSWER QUESTIONS

Question 1.
Write a note on bacteriophages. (Dharwar. 2004, Belgaum. 04,2005)
Solution:
The viruses that infect bacteria are called bacteriophages. They were discovered by Twort. They are Tadpole shaped. They have DNA as their genetic material. They are distinguished into T – odd phages as well as T – even phages.

Question 2.
What is a taxonomic aid?
Solution:
A taxonomic aid is storage of record of either live or dead specimens of flora or fauna, which helps scientists in taking reference to study classification

Question 3.
Give the classification of man.
Solution:
Common Name – Human
Scientific Name – Homo sapiens
Genera – Homo
Families – Hominidae
Orders – Primata
Classes – Mammalia
Phyla/Division – Chordate

Question 4.
What is a museum? How many kinds of museums are found?
Solution:
Museum in an institution where artistic and educational materials are exhibited to the public. The material available for observation and study is called a collection.
Kinds of Museums:

  • Art Museum
  • History Museum
  • Applied Science Museum
  • Natural Science Museum

Question 5.
Give a reason for the following.
Bacteria are the Natural Scavengers ‘ (D.Kannada 2006)
Solution:
because they bring about the decomposition of organic debris and clean the earth’s surface.

Question 6.
What is the role of characteristics of living beings in classification?
Solution:
A group of common features of living beings are placed under a common category of classification and when uncommon under a different category. It means more systematic a process for further study, research, protection and recording.

Question 7.
What is the significance of a HERBARIUM?
Solution:
HERBARIUM:- A book, case, or room containing an orderly collection of dried plants is called Herbarium. It develops interest in Nature for the activists in it. It can be used to gain knowledge and be updated about plants and their scientific names and even compare various samples. It is a small scale it can be proactive to do. One can make projects too from it for schools, colleges and research institutions.

Question 8.
Explain the role of blue-green algae in soil fertility.
Solution:
Blue-green algae like Nostoc, Anabaena fix atmospheric nitrogen. Heterocyst contains nitrogens enzyme that helps in nitrogen fixation. Nitrogen-fixing blue-green algae are inoculated in the rice field to increase soil fertility.

LONG ANSWER QUESTIONS

Question 1.
Write a short note on Binomial Nomencia? ture and guidelines for Binomial nomenclature.
Solution:
Binomial Nomenclature was introduced by Carolus Linnaeus. In this method every organism is given a scientific name, which has two parts, the first is the name of the genus (generic name) and the second is the name of the species (specific epithet) e.g.: Homo sapiens In the above examples, Homo is a generic name, while sapiens is the name of the species belonging to Homo.

Guidelines:

  • scientific names are generally in Latin or derived from Latin irrespective of their origin
  • The scientific names are written in italics or underlined (when handwritten)
  • The first word denotes the name of the genus and the second word denotes the specific epithet
  • The generic name starts with a capital letter, while the specific name starts with a small letter (If a specific name starts with a capital letter it denotes the name of a person or place)
  • The name of the author is written in an abbreviated form after the specific name. e.g.: Homo sapiens Linn.

Question 2.
What is the difference between living and nonliving?
Solution:
Question 3.
Explain the binomial system of nomenclature.
Solution:
Binomial nomenclature system was developed by Linnaeus. Binomial nomenclature is the system of providing organisms with appropriate and distinct names consisting of two words, first generic and second specific. The first or 4.

  • generic word is also called genus. It is like a noun and its first letter is written in capital form.The second word or specific epithet represents the species.
  • It is like an adjective. Its first letter is written in small form except occasionally when it denotes a person or place. The two word name is appended with the name of the taxonomist who discovered the organism and provided with its scientific name, e.g., Ficus bengalensis L., Mangifera indica Linn, The name of taxonomist can be written in full or in abbreviated form.
  • There are several technical names which have three words, e.g., Homo sapien sapiens, Acacia nilotica indica, Gerilla gorilla. Here the first word is generic, the second specific while the third word represents variety (mostly in botanical literature) or subspecies (mostly in zoological literature).
  • If the same scientific name is to be written time and again, the name of the genus can be abbreviated, e.g., F. bengalensis.

Question 4.
What is the role of zoological parks in wildlife conservation?
Solution:

  • In the early stages, the zoological parks were considered as places of relaxation and enjoyment for public, however, there has been a change in the objective of the purposefulness of these parks.
  • The establishment of zoological parks help in providing knowledge about different native and exotic wild mammals, birds, reptiles, fish and flora to the public in general and school children in particular.
  • Since the key to wildlife conservation lies in the education of the masses and the involvement of voluntary organisations, zoological parks are very useful in spreading knowledge on the wildlife wealth of the country.
  • These are also important centres for organising seminars, training and researches on the management of wildlife species and for study of their social behaviour, breeding and ecological species.

We hope the NCERT Solutions for Class 11 Biology at Work Chapter 1 The Living World, help you. If you have any query regarding NCERT Solutions for Class 11 Biology at Work Chapter 1 The Living World, drop a comment below and we will get back to you at the earliest.