Chapter 4: Animal Kingdom – Long Answer Type Questions
CBSE Class 11 Biology Long Answer Questions – Chapter 4: Animal Kingdom (NCERT Based)
Course Details
Course: CBSE Class 11 Biology
Syllabus: NCERT
Unit: Unit I – Diversity in Living World
Chapter: Chapter 4 – Animal Kingdom
CBSE Board Examination: Central Board of Secondary Education – Class 11 (School & Annual Examinations)
CBSE Class 11 Biology Chapter 4 Animal Kingdom – 25 Long Answer Questions with Answers (NCERT)
Section A: Basis of Classification (Q1–Q5)
Q1. Explain the basis of classification in the Animal Kingdom.
Animals are classified based on fundamental structural and functional features that indicate evolutionary complexity. These include levels of organisation (cellular to organ-system), body symmetry (asymmetrical, radial, bilateral), number of germ layers (diploblastic or triploblastic), nature of body cavity (acoelomate, pseudocoelomate, coelomate), segmentation, and presence or absence of notochord. These criteria help in systematic grouping, identification, and understanding evolutionary relationships among animals.
Q2. Describe the significance of body symmetry and coelom in animal classification.
Body symmetry reflects the mode of life and movement in animals. Radial symmetry suits sessile or slow-moving forms, while bilateral symmetry supports active locomotion. Coelom provides space for internal organs, allowing better physiological efficiency and development of complex organ systems. Presence of true coelom marks evolutionary advancement.
Q3. Explain the importance of germ layers in classification.
Germ layers determine the complexity of body organisation. Diploblastic animals have tissue-level organisation, while triploblastic animals develop complex organs and systems, indicating higher evolutionary status.
Q4. What is notochord? Explain its role in classification.
Notochord is a flexible rod-like structure providing support. Its presence distinguishes chordates from non-chordates and reflects advanced organisation.
Q5. How does segmentation contribute to evolutionary advancement?
Segmentation allows specialisation of body segments, improving locomotion and efficiency, seen in annelids and arthropods.
Section B: Non-Chordates (Q6–Q15)
Q6. Describe the general characteristics of phylum Porifera.
Poriferans are aquatic, mostly marine animals with cellular organisation. Their porous body has a canal system for water circulation. Skeleton consists of spicules or spongin. They are asymmetrical and show high regenerative capacity.
Q7. Explain the canal system in sponges.
The canal system consists of ostia, spongocoel, and osculum, enabling water flow for feeding, respiration, and waste removal.
Q8. Describe the characteristic features of phylum Cnidaria.
Cnidarians are diploblastic, radially symmetrical animals with tissue-level organisation. They possess cnidocytes for defence and prey capture and show polyp and medusa forms.
Q9. Write a note on phylum Ctenophora.
Ctenophores are marine, diploblastic animals with biradial symmetry and locomotion by comb plates. Bioluminescence is a distinctive feature.
Q10. Explain the features of Platyhelminthes.
Flatworms are triploblastic, bilaterally symmetrical, and acoelomate animals, mostly parasitic with adaptations like suckers.
Q11. Describe the general characteristics of Aschelminthes.
They are cylindrical, pseudocoelomate worms with complete digestive system and separate sexes, often parasitic.
Q12. Explain why Annelida is considered evolutionarily advanced.
Annelids show true coelom, metameric segmentation, closed circulatory system, and organ-system level organisation.
Q13. Describe the general features of Arthropoda.
Arthropods possess jointed appendages, chitinous exoskeleton, open circulatory system, and show maximum diversity.
Q14. Write the characteristic features of Mollusca.
Molluscs have soft unsegmented body divided into head, foot, and visceral mass, with mantle secreting shell.
Q15. Describe phylum Echinodermata.
Echinoderms are marine animals with spiny skin, water vascular system, endoskeleton, and radial symmetry in adults.
Section C: Hemichordata & Chordates (Q16–Q25)
Q16. Why is Hemichordata considered a connecting link?
They show pharyngeal gill slits like chordates but lack true notochord, showing mixed features.
Q17. Describe the general characteristics of chordates.
Chordates possess notochord, dorsal hollow nerve cord, pharyngeal gill slits, and post-anal tail at some stage of life.
Q18. Explain the features of Protochordata.
Protochordates include Urochordata and Cephalochordata with notochord present partially or throughout life but lacking vertebral column.
Q19. Write a note on Vertebrata.
Vertebrates possess vertebral column, cranium, and advanced organ systems, making them highly evolved chordates.
Q20. Describe the characteristics of Cyclostomata.
They are jawless vertebrates with circular mouth, cartilaginous skeleton, and parasitic mode of life.
Q21. Explain the general features of Pisces.
Pisces are aquatic vertebrates with gills for respiration, fins for locomotion, and streamlined body.
Q22. Describe class Amphibia.
Amphibians live on land and water, have moist skin, and require water for reproduction.
Q23. Write the characteristic features of Reptilia.
Reptiles have dry scaly skin, internal fertilisation, and shelled eggs, adapting them to terrestrial life.
Q24. Describe the features of class Aves.
Birds have feathers, wings, pneumatic bones, and are adapted for flight with high metabolic rate.
Q25. Explain the general characteristics of Mammalia.
Mammals possess mammary glands, hair, diaphragm, and are mostly viviparous with advanced brain development.
Exam Relevance
✔ Strictly NCERT-aligned
✔ Ideal for 5-mark CBSE Class 11 questions
✔ Covers full non-chordate and chordate classification
✔ Strong focus on characteristics and evolutionary trends