Biology - Chapter 4: Animal Kingdom
Classification Based on Coelom, Symmetry, and Notochord
1. Basis of Classification
| Basis | Types | Examples |
|---|---|---|
| Symmetry | Radial, Bilateral | Coelenterata, Annelida |
| Coelom | Acoelomate, Coelomate | Platyhelminthes, Chordata |
| Circulatory System | Open, Closed | Arthropoda, Annelida |
2. Important Questions & Answers
Q1. What are the main characteristics of Phylum Porifera?
Answer:
Porifera are commonly known as sponges.
1. Body organization is at cellular level.
2. Water canal system is present.
3. Water enters through Ostia and exits through Osculum.
Example: Sycon, Spongilla.
Porifera are commonly known as sponges.
1. Body organization is at cellular level.
2. Water canal system is present.
3. Water enters through Ostia and exits through Osculum.
Example: Sycon, Spongilla.
Q2. What is the function of Cnidoblasts in Cnidaria?
Answer: Cnidoblasts help in capturing prey, defense, and attachment. They contain poisonous substances that paralyze the prey.
Q3. Why is Arthropoda the largest phylum?
Answer: Arthropods form about two-thirds of all known species. Their success is due to:
• Chitinous exoskeleton
• Jointed appendages
• Adaptability to various environments
• Chitinous exoskeleton
• Jointed appendages
• Adaptability to various environments
Q4. Why are Earthworm and Leech placed in Annelida?
Answer: Because their body is divided into segments (metameres). They also have a true coelom and closed circulatory system.
Q5. Difference between Chordata and Non-Chordata?
Answer:
• Chordata have a notochord; Non-chordata do not.
• Nervous system is dorsal and hollow in chordates.
• Pharyngeal gill slits are present in chordates.
• Chordata have a notochord; Non-chordata do not.
• Nervous system is dorsal and hollow in chordates.
• Pharyngeal gill slits are present in chordates.
Q6. Difference between Amphibians and Reptiles?
Answer:
Amphibians have moist skin and require water for reproduction (e.g., frog).
Reptiles have dry, scaly skin and can live fully on land (e.g., lizard, snake).
Amphibians have moist skin and require water for reproduction (e.g., frog).
Reptiles have dry, scaly skin and can live fully on land (e.g., lizard, snake).
Q7. What are the unique features of Mammals?
Answer: Mammals have mammary glands to feed their young. They also have hair on the body and external ears (pinna).