NCERT Solutions Class 11 Biology Chapter 4 Animal Kingdom

NCERT Solutions for class 11 Biology Chapter-04 Animal Kingdom: The chapter on Animal Kingdom is important for students approaching the board exams. This article introduces NCERT solutions designed to help students explain the concepts of further learning and how to write to get good grades on exams. The solutions are presented in very simple language for ease of understanding.

NCERT CBSE Chapter 04 Animal Kingdom of Class 11 Biology explains how the need for classification becomes all the more important. It further explains how classification also helps in assigning a systematic position to newly described species. Revise the basic concepts of Animal Kingdom for quick revision and class notes.

Q1: What are the difficulties that you would face in the classification of animals if common fundamental features are not taken into account?

Answer:

Animals are classified according to their characteristics & common fundamental features such as cell organization, coelom type, circulation, digestive tract, body symmetry, and reproductive system.  It is impossible to handle each creature uniquely without these common traits, and it is impossible to add new species discovered every day without them. To investigate animal diversity, classification must be based on common basic characteristics.

Q2: If you are given a specimen, what are the steps that you would follow to classify it?

Answer:

Steps used for animal classification are: (i) level of classification (ii) body cavity (iii) body symmetry (iv) nature of coelom (v) type of true coelom.

Q3: How useful is the study of the nature of the body cavity and coelom in the classification of animals?

Answer:

The nature of the body cavity and coelom gives important clues for the classification of animals. The absence of coelom means that the animal has not developed a division of labor for various biological activities. On the other hand, the presence of coelom shows further evolution from simple to more complex organisms.

Q4: Distinguish between intracellular and extracellular digestion. 

Answer:

Intracellular Digestion	Extracellular Digestion
Intracellular digestion is the breakdown of substances within the cytoplasm of a cell.	A form of digestion wherein the breaking down of materials into smaller, absorbable components takes place outside the cell.
Occurs in unicellular organisms	Occurs in multicellular organisms
In intracellular digestion, only chemical digestion takes place.	In extracellular digestion, both chemical and mechanical digestion occurs.
Digestive enzymes involve lysozyme that secretes into the food vacuole.	Digestive enzymes are secreted from the glands of the alimentary canal.
Ingestion occurs through the phagocytic vesicles.	Ingestion occurs through the mouth.

Q5: What is the difference between direct and indirect development?

Answer:

Direct Development	Indirect Development
Type of development in which a young is directly born as a small version of an adult.	In this type of development, an animal born is different from the adult form.
There is no intermediate form such as the larva of the animal.	The embryo hatches from the egg in a larval form.
There is no metamorphosis.	The larva undergoes a process of metamorphosis to become its adult stage.
The animals that experience direct development are fishes, reptiles, birds, and mammals.	Amphibians, some echinoderms, and some arthropods such as insects undergo indirect development.

Q6: What are the peculiar features that you find in parasitic Platyhelminthes? 

Answer:

Peculiar features of parasitic Platyhelminthes:

• They have dorso-ventrally flattened bodies, hence are called flatworms.
• These are mostly endoparasites found in animals including human beings.
• Flatworms are bilaterally symmetrical, triploblastic, and acoelomate animals with organ level of organization.
• Hooks and suckers are present in parasitic forms. Some of them absorb nutrients from the host directly through their body surface.
• Specialised cells called flame cells help in osmoregulation and excretion.
• Sexes are not separate. Fertilization is internal and development is through many larval stages. Some members like Planaria possess high regeneration capacity.
• Examples: Taenia (Tapeworm), Fasciola (Liver fluke).

Q7: What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?

Answer:

The phylum Arthropoda is the largest phylum with altogether 83% of the total known species of animals. The reasons are:

1. They have jointed legs for easy mobility.
2. They have a hard exoskeleton that protects their body and helps to reduce water loss so they adapt more to terrestrial conditions.

Q8: Water vascular system is the characteristic of which group of the following:

• (a) Porifera (b) Ctenophora (c) Echinodermata (d) Chordata.

Answer:

The water vascular system is characteristic of c) Echinodermata.

Q9: “All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.

Answer:

There is the presence of a notochord and paired pharyngeal gill slits in Chordates. But in Vertebrates, the notochord is replaced by a cartilaginous or bony vertebrate column. So, this characteristic feature justifies the statement “All vertebrates are chordates but all chordates are not vertebrates”.

Q10: How important is the presence of an air bladder in Pisces?

Answer:

The air bladder contains gas, usually oxygen, and functions as a hydrostatic organ. 

1. It helps fish maintain their depth without floating upward or sinking. 
2. It also serves as a resonating chamber to produce or receive sound.

Q11: What are the modifications that are observed in birds that help them fly?

Answer:

1. Instead of heavy jaws and teeth, they have lightweight beaks.
2. Instead of fur, they have feathers. These are light, streamlined, and cleverly adjustable for flight control.Their bones are also hollow making them lighter for flight.

Q12: Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?

Answer:

No, the number of eggs or young ones produced by an oviparous and viviparous mother wouldn’t be equal because oviparous animals produce more eggs in number to keep them safe from external environmental conditions and predators. While, viviparous animals produce their eggs inside the body in safe conditions, hence, producing less number of eggs.

Q13: Segmentation in the body is first observed in which of the following:

• (a) Platyhelminthes (b) Aschelminthes (c) Annelida (d) Arthropoda

Answer:

Segmentation in the body is first observed in c) Annelida.

Q14: Match the following:

1. (a) Operculum               (i) Ctenophora
2. (b) Parapodia                (ii) Mollusca
3. (c) Scales                      (iii) Porifera
4. (d) Comb plates            (iv) Reptilia
5. (e) Radula                      (v) Annelida
6. (f ) Hairs                         (vi) Cyclostomata and Chondrichthyes
7. (g) Choanocytes           (vii) Mammalia
8. (h) Gill slits                    (viii) Osteichthye

Answer:

Correct match: 

1. a) Operculum                 viii) Osteichthye
2. b) Parapodia                   v) Annelida
3. c) Scales                         iv) Reptilia
4. d) Comb Plates               i) Ctenophora
5. e) Radula                        ii) Mollusca
6. f) Hairs                            vii) Mammalia
7. g) Choanocytes              iii) Porifera
8. h) Gill Slits                      vi) Cyclostomata and Chondrichthyes

Q15: Prepare a list of some animals that are found parasitic in human beings.

Answer:

Below are some animals that are found parasitic on human beings:

• Taenia solium (Pork tape worm) 
• Wuchereria (Filarial worm) 
• Ancylostoma (Hookworm) 
• Pediculus (Head louse)
• Schistosoma (Blood fluke) 
• Ascaris (Roundworm)