The VIDYANKER team has thoughtfully prepared the NCERT Solutions for Class 11 Biology Chapter 4, "Animal Kingdom" These solutions are designed to help you tackle the NCERT textbook questions with ease. We recommend going through the chapter's theory before diving into the solutions for a deeper understanding. Feel free to share these NCERT Solutions for Class 11 Biology with others—learning is always better when shared!
NCERT TEXTBOOK QUESTIONS SOLVED
1. What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account?
Ans: If we consider some characteristic rather than fundamental features then every organism will be placed in a different group and the whole aim of classification would not be achieved.
The classification of animals is also used to compare different organisms and judge their individual evolutionary significance. If only one characteristic is considered, then this objective would not be achieved.
2. If you are given a specimen, what are the steps that you would follow to classify it?
Ans: Several steps considered to classify a specimen are
(A)Mode of nutrition – It can be autotrophic, holozoic, saprophytic or parasitic.
(B)Complexity of body structure – Whether the specimen is unicellular or multicellular.
(C)Presence or absence of membrane bound organelles .
(D)Body symmetry, i.e., the plane by which organism can be divided into two equal halves.
(E)Presence or absence of coelom, it can be acoelomates, pseudoco elomates, eucoelo- mates.
(F)Phylogenetic relationship.
3. How useful is the study of the nature of body cavity and coelom in the classification of animals?
Ans: Coelom is a fluid filled space between the body wall and digestive tract. The presence or absence of body cavity or coelom plays a very important role in the classification of animals. Animals that possess a fluid filled cavity between body wall and digestive tract are known as coelomates. Annelids, mollusks, arthropods, echinodermates, and chordates are examples of coelomates. On the contrary, those animals in which the body cavity is not lined by the mesoderm are called pseudoco elomates. In such animals, mesoderm is scattered in between the ectoderm and endoderm. Asch elminthes is an example of pseudoco elomates. In some animals, there is no existence of body cavity.
4. Distinguish between intracellular and extracellular digestion?
Ans: The coelom is the body cavity or fluid-filled space lined by the mesoderm, and an animal with a coelom is called a coelomate. In some animals, the body cavity is not covered by the mesoderm; instead, the mesoderm is a scattered cyst between the ectoderm and the endoderm. Such a body cavity is called a pseudocoelom, and the animals that have them are called pseudocoelomates, for example, Aschelminthes. Some animals do not have a body cavity; they are known as acoelomates, such as Platyhelminthes.
Classification of the body cavity and coelom is important in deciding the complexity of an organism at the organ level.
5. What is the difference between direct and indirect development?
Ans: Differences between direct development and indirect development are :
| Direct development | Indirect development |
|---|---|
| Young ones may resemble the adult. | In this young hatchlings (larvae) do not resemble the adult |
| Intermediate stages are absent | Intermediate stages are present. |
| Metamorphosis is absent. | Metamorphosis is seen in indirect development |
| E.g., Hydra, man | E.g., Frog, cockroach |
6. What are the peculiar features that you find in parasitic platyhelminthes?
Ans: Following are the peculiar features of parasitic platyhelminthes:
(i) The thick tegument (body covering) resistant to the host's digestive enzymes and anti-toxins.
(ii)Adhesive organs like suckers in flukes and the hooks and suckers in tape worms for a firm grip on or in the host's body.
(iii)Loss of locomotory organs.
(iv) Digestive organs are absent in tape worms because digested and semi digested food of the host is directly absorbed' through the body surface.
(v) Reproductive system is best developed in parasitic flatworms.
(vi)Parasitic flatworms, such as liver fluke and tapeworms perform anaerobic respiration.
(vii)They possess a considerable osmotic adaptability, as they can successfully live in different media.
7. What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?
Ans: Arthropods are the first group to possess well-developed systems to perform different activities. There exists a separate system for respiration, locomotion, and reproduction. Their survival capacity is very good due to the elaborate system. This makes them survive in various conditions. Such might be one of the reasons why arthropods form the largest group of the animal kingdom.
8. Water vascular system is the characteristic of which group of the following:
(a) Porifera (b) Ctenophora (c) Echinodermata (d) Chordata
Ans: (c) Echinodermata
9. "All vertebrates are chordates but all chordates are not vertebrates". Justify the statement.
Ans: A characteristic of the phylum chordate is the presence of a notochord and paired pharyngeal gill slits. However, in adults, the vertebrata notochord found in the embryo within the subfilm is replaced by columns of bony vertebrae. It is, therefore said that "All vertebrates are chordates, but not all chordates are vertebrates".
10. How important is the presence of air bladder in Pisces?
Ans: Bony fishes possess a sac-like outgrowth, the swim bladder also known as air bladder, which comes up as an outgrowth from the dorsal wall of oesophagus. It is hydrostatic in function. Buoyancy is held regulated and thus prevents them from sinking. They may swim up and down. In some air bladder helps for respiration. It also acts as resonating chamber for producing or receiving sound.
11. What are the modifications that are observed in birds that help them fly?
Ans: The following are the variations found in birds to help them fly:
(i) Feathers.
(ii) Forelimbs which are turned into wings to help in flights.
(iii) Hind limbs provided with scales.
(iv) Pneumatic or hollow bones lighten the skeleton.
(v) Absence of urinary bladder results in the net body weight loss and enables them to fly.
(vi) Streamlined body causes less resistance and enables them for longer flight.
12. Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
Ans: No, the number of eggs or young ones produced by an oviparous and viviparous mother are not equal. The number of eggs produced by oviparous mothers is more comparatively because, in oviparous animals, fertilization takes place outside the uterus, whereas in viviparous animals' development takes place inside the uterus, which makes successful incubation of young animals less.
Since eggs are immobile and exist outside, there is a probability of being eaten by predators. Therefore, to maintain the progeny, there should be a greater number of eggs.
13. Segmentation in the body is first observed in which of the following:
(a) Platyhelminthes (b) Aschelminthes (c) Annelida (d) Arthropoda
Ans: (c) Annelida
14.Match the following:
| Column 1 | Column 2 |
|---|---|
| (a) Operculum | (i) Ctenophora |
| (b) Parapodia | (ii) Mollusca |
| (c) Scales | (iii) Porifera |
| (d) Comb plates | (iv) Reptilia |
| (e) Radula | (v) Annelida |
| (f) Hairs | (vi) Cyclostomata and Chondrichthyes |
| (g) Choanocytes | (vii) Mammalia |
| (h) Gill slits | (viii) Osteichthyes |
Ans:
| Column 1 | Column 2 |
|---|---|
| (a) Operculum | (viii) Osteichthyes |
| (b) Parapodia | (v) Annelida |
| (c) Scales | (iv) Reptilia |
| (d) Comb plates | (i) Ctenophora |
| (e) Radula | (ii) Mollusca |
| (f) Hairs | (vii) Mammalia |
| (g) Choanocytes | (iii) Porifera |
| (h) Gill slits | (vi) Cyclostomata and Chondrichthyes |
15. Prepare a list of some animals that are found parasitic on human beings.
Ans: List of some animals that are found parasitic on human beings :
| Parasite | Nature Endoparasites | Organ |
|---|---|---|
| Taenia solium (Pork Tapeworm) | Endoparasites | Small intestine |
| Schistosoma (Blood fluke) | Endoparasites | Hepatic portal system and mesenteric blood vessels. |
| Ancylostoma duodenale (Hook worm) | Endoparasites | Small intestine |
| Wuchereria (Filarial worm) | Endoparasites | Lymph nodes and lymphatic vessels |
| Enterobius (Pin worm) | Endoparasites | Colon, caecum ог vermiform appendix |
