Animal Kingdom
NCERT Class 11 Biology | CBSE | NEET-UG Preparation
Study the basis of animal classification, the major non-chordate phyla, chordate characteristics and vertebrate classes. Revise important definitions, identifying features, examples and comparisons for CBSE examinations and NEET-UG.
Short-Answer Questions
Attempt these questions before checking the answers. They cover important definitions, distinguishing features and comparisons.
Questions
Q1. Differentiate between radial and bilateral symmetry.
Q2. Define diploblastic and triploblastic animals with examples.
Q3. Distinguish between acoelomates and pseudocoelomates.
Q4. State two characteristic features of Porifera.
Q5. What are cnidocytes? State their function.
Q6. What is the function of flame cells?
Q7. Mention two distinguishing features of Arthropoda.
Q8. What is the water vascular system, and in which phylum is it found?
Q9. List the fundamental features of chordates.
Q10. State two differences between Chondrichthyes and Osteichthyes.
Answers
Answer 1: Radial symmetry allows multiple planes through the central axis to divide the body into similar halves. Bilateral symmetry allows only one plane to divide the body into right and left halves.
Answer 2: Diploblastic animals develop two germ layers, ectoderm and endoderm; Cnidaria is an example. Triploblastic animals develop ectoderm, mesoderm and endoderm; Annelida is an example.
Answer 3: Acoelomates lack a body cavity, as in Platyhelminthes. Pseudocoelomates have a body cavity that is not completely lined by mesoderm, as in Aschelminthes.
Answer 4: Poriferans possess a water canal system with pores, and their skeleton may contain spicules or spongin fibres. Choanocytes help generate water currents and capture food.
Answer 5: Cnidocytes are specialised cells of Cnidaria. They contain nematocysts used mainly for defence and prey capture.
Answer 6: Flame cells function in excretion and osmoregulation in Platyhelminthes.
Answer 7: Arthropods possess jointed appendages and a chitinous exoskeleton. They generally have an open circulatory system.
Answer 8: The water vascular system is a specialised system that assists locomotion, food capture and respiration in Echinodermata.
Answer 9: The fundamental features are the notochord, dorsal hollow nerve cord, pharyngeal gill slits, post-anal tail and endostyle or thyroid gland, present at least at some stage of development.
Answer 10: Chondrichthyes have a cartilaginous endoskeleton and generally lack an operculum and swim bladder. Osteichthyes have a primarily bony endoskeleton, an operculum and usually a swim bladder.
