NCERT Solutions for Class 11 Biology Chapter 4 - Animal Kingdom

Did you know that sponges, insects, birds, and humans all belong to the same kingdom? Chapter 4 explores this wide range of animal life and how it’s classified based on body structure, level of organisation, and more. The NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom are written in a simple, clear way to help students understand classification without confusion. The solutions cover all exercise questions with complete, well-structured answers. NCERT Solutions offer clear explanations to simplify learning about animal classification.

This Story also Contains

1. NCERT Solutions For Class 11 Biology Chapter 4 PDF Download
2. Access the NCERT Solutions for Class 11 Biology Chapter 4 (Exercise Questions)
3. Approach to solve questions of Class 11 Chapter 4
4. Important question of Class 11 Chapter 4
5. What extra should students study beyond the NCERT for NEET?
6. Chapter Wise NCERT Solutions for Class 11 Biology

This chapter includes detailed classifications from Porifera to Chordata, with key features, examples, and diagrams. The solutions help students remember the differences between phyla and write clear, point-wise answers in exams. Whether for quick revision or concept clarity, these NCERT Solutions make it easier to study one of the lengthiest chapters in the Class 11 Biology syllabus.

Also Read,

• NCERT Notes for class 11 biology Animal Kingdom
• NCERT Exemplar for class 11 biology Animal Kingdom

NCERT Solutions For Class 11 Biology Chapter 4 PDF Download

Need help with animal classification? Chapter 4 covers everything from sponges to mammals, and it can feel like a lot. That’s why having ready-to-use solutions makes a big difference. With simple explanations, labelled diagrams, and step-by-step answers, students can clear doubts quickly and revise smarter. Download the PDF of NCERT Solutions for Class 11 Biology Chapter 4 Animal Kingdom and keep it saved for anytime, offline study—perfect for last-minute prep or regular review.

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Access the NCERT Solutions for Class 11 Biology Chapter 4 (Exercise Questions)

Given below are the exercise questions with detailed explanations for better understanding.

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

Answer: Basic characteristics help in grouping animals while indicating their differences. All animals do not have cell walls and are dependent on other organisms for nutrition, but mammals have special characteristics such as mammary glands.

Without these basic characteristics, it would be hard to classify because:

• We will not be able to observe how animals are related.
• Classification of animals would be confusing.
• Studying how animals evolved would be harder.

In brief, basic characteristics are responsible for classifying animals and telling us about their evolution.

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

Answer: To identify an unknown specimen, look at these most important features:

1. Level of Organisation: Cells, tissues, or organs.

2. Body Symmetry: Radial or bilateral.

3. Germ Layers: Two (diploblastic) or three (triploblastic).

4. Body Cavity: Present or absent.

5. Coelom: True (coelomate), false (pseudocoelomate), or none (acoelomate).

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

Answer: The coelom and body cavities are important in the classification of animals. A coelom is a body cavity filled with fluid, lined by embryonic tissue.

• True coelomates are annelids, molluscs, arthropods, echinoderms, hemichordates, and chordates.
• Animals that lack a coelom (acoelomates) are Porifera, Coelenterata (Cnidaria), ctenophores, and platyhelminths.
• A pseudocoelom is present in some animals, which is not lined completely by mesoderm but develops from the blastocoel of the embryo. Aschelminthes fit into this category.

Dividing animals into categories according to their coelom helps us to understand their development and evolutionary history.

Q4. Distinguish between intracellular and extracellular digestion.

Answer: The differences between intracellular and extracellular digestion are as follows

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

Answer: The differences between direct and indirect development are as follows

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

Answer:– Platyhelminthes have several unique characteristics:

1. They have a thick tegument that shields them from the digestive enzymes of their hosts.

2. Their bodies are dorsoventrally flattened, i.e., flat from top to bottom.

3. They have suckers and hooks that help them in sticking to their hosts and obtaining nutrition.

4. They do not possess organs for movement, so they use other means to move.

5. Their reproductive system is well developed, and they are mostly hermaphroditic, having both male and female reproductive organs.

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

Answer: The reasons for arthropods being the largest group of animals are as follows:

1. They have a thick cuticle that helps them to thrive in many types of environments, particularly on land.

2. They have striated muscles that help in rapid and effective movement.

3. They have a tracheal system of respiration that brings oxygen directly to their cells, which is extremely effective.

4. They possess joint appendages that are capable of performing numerous different functions, so they are very adaptable.

5. They have a highly developed nervous system and sense organs that help them effectively sense and react to their surroundings.

6. They communicate using pheromones, which help in social behaviour and reproduction.

Q8. The water vascular system is characteristic of which group of the following:

(a) Porifera

(b) Ctenophora

(c) Echinodermata

(d) Chordata

Answer: The correct option is (c) Echinodermata

The water vascular system is a characteristic feature of echinoderms which helps in locomotion, respiration and capturing of food.

Q9. "All vertebrates are chordates but all chordates are not vertebrates." Justify the statement.

Answer: Phylum Chordata contains animals that have a notochord, i.e., an elastic rod-shaped structure. Phylum Chordata is still divided into three sub-phyla: Urochordata, Cephalochordata, and Vertebrata. During vertebrates, the notochord is superseded by a vertebral column, but within urochordates and cephalochordates, there is no vertebral column present. Therefore, all vertebrates are chordates, but they are not necessarily vertebrates, as they can also be urochordates or cephalochordates.

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

Answer: Osteichthyes (bony fishes, such as salmon) have an air bladder, which keeps them buoyant and prevents them from sinking in water. It makes them remain at a specific depth without swimming continuously. Chondrichthyes (cartilaginous fishes, such as sharks) do not have an air bladder. They need to swim continuously, employing their fins and body to remain afloat to avoid sinking.

The air bladder functions as a buoyancy support, whereas sharks survive using motion.

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

Answer: Birds have some adaptations that help them to fly:

• They have light bones with air-filled cavities, which lighten their load and reduce the effort of flying.
• A streamlined body cuts the resistance of the air, making it move smoothly through the air.
• Powerful flight muscles help in flapping the wings.
• The front limbs are modified into wings for flight, and the hind limbs are used for walking and perching.
• Additional air sacs in their body supply sufficient oxygen for extensive flights.
• These adaptations render birds ideally suited to flight.

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

Answer: Oviparous creatures lay eggs outside the body and generally give birth to a greater number of offspring, as they are given little parental care and exposed to severe environmental conditions. Viviparous creatures, on the other hand, give birth to live offspring and offer care both pre- and post-birth. This greater parental care leads to greater survival rates, reducing the necessity for a high number of offspring. Thus, the number of eggs or young ones given birth to by oviparous and viviparous mothers is not the same.

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

(a) Platyhelminthes

(b) Aschelminthes

(c) Annelida

(d) Arthropoda

Answer: The correct option is (c) Annelida

Q14. 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 ) Hairs (vi) Cyclostomata and Chondrichthyes
(g) Choanocytes (vii) Mammalia
(h) Gill slits (viii) Osteichthyes

Answer: (a)-(viii), (b)-(v), (c)-(iv), (d)-(i), (e)-(ii), (f)- (vii), (g)- (iii), (h)- (vi)

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

Answer: Taenia ( Tapeworm)

Ascaris (roundworm)

Ancylostoma (hookworm)

Enterobius (pinworm)

Wuchereria (filarial worm)

NCERT Solutions for Class 11: Subject-wise

• NCERT Solutions for Class 11 Maths
• NCERT Solutions for Class 11 Chemistry
• NCERT Solutions for Class 11 Physics

Approach to solve questions of Class 11 Chapter 4

The NCERT Solutions for Class 11 give clear and detailed answers to all questions of the chapter according to the latest CBSE syllabus. The approach to solving questions of the Animal Kingdom involves a clear understanding of the animal kingdom. Students can follow the steps given below:

• To understand the diversity of the animal kingdom easily, firstly, it's important to understand the classification of animals based on various features such as body symmetry, coelom, segmentation, etc.
• Go through all the terminologies like asymmetry, radial symmetry, bilateral symmetry, and open/closed circulatory systems, to grasp the concepts effectively.
• Prepare a table by writing down all the distinguishing features of major phyla like Arthropoda, Mollusca, Chordata, etc.
• Study the features of these phyla using diagrams, as it will help you to understand and remember their characteristics better, and for a longer time.
• Try to solve a lot of questions from this chapter to gain confidence while answering the questions in the exam, and to get familiar with the pattern as well.

Important question of Class 11 Chapter 4

This chapter is very vast and interesting, focusing on key questions can help you understand its complexity and classification.

Question 1: The following are the statements about non-chordates:
A. gill slits perforate the pharynx.
B. Notochord is absent.
C. The central nervous system is dorsal.
D. Heart is dorsal if present.
E. Tail behind the body
Choose the most appropriate answer from the options given below:

1. A & C only

2. A, B & D only

3. B, D & E only

4. B, C & D only

Answer:

In invertebrates, the notochord, a defining feature of chordates, is absent, and their body structure is often supported by other means, like exoskeletons or hydrostatic skeletons. If a heart is present, it is typically located dorsally, unlike the ventral heart found in chordates. In addition, they lack a tail behind the body, which is a characteristic feature of chordates and plays a role in locomotion or balance in those organisms.

Hence, the correct answer is option 3, B, D & E only

Also, check the NCERT Books and the NCERT Syllabus here:

• NCERT Books Class 11 Biology
• NCERT Syllabus Class 11 Biology
• NCERT Books Class 11
• NCERT Syllabus Class 11

What extra should students study beyond the NCERT for NEET?

To do well in NEET, students should study extra topics and practice more beyond the NCERT, as shown in the table below.

Chapter Wise NCERT Solutions for Class 11 Biology

Below are the chapter-wise solutions: