Animal Classification
Short Questions
1. What distinguishes natural classification from artificial classification?
Answer : Natural classification uses multiple criteria like body organization and evolution, unlike artificial’s focus on observable traits.
2. Why is the notochord significant in chordate classification?
Answer : It provides structural support and is a defining feature of chordates.
3. How does protoplasmic grade differ from cellular grade organization?
Answer : Protoplasmic grade is in unicellular organisms; cellular grade lacks tissues in multicellular organisms.
4. What evolutionary insight does bilateral symmetry provide?
Answer : It indicates advanced locomotion and cephalization in animals.
5. Why are Cnidarians considered diploblastic?
Answer : They have only ectoderm and endoderm germ layers.
6. What role does the coelom play in animal classification?
Answer : It classifies animals as acoelomate, pseudocoelomate, or eucoelomate based on cavity formation.
7. How does segmentation benefit animals like Annelids?
Answer : It allows flexibility and specialized functions in body segments.
8. What makes Porifera the simplest multicellular animals?
Answer : They lack tissues and have cellular grade organization.
9. Why are cnidoblasts unique to Phylum Cnidaria?
Answer : They are specialized cells for prey capture and defense.
10. What is the significance of chitin in Arthropods?
Answer : It forms a protective, flexible exoskeleton.
11. How do Platyhelminthes differ from Aschelminthes in body cavity?
Answer : Platyhelminthes are acoelomate; Aschelminthes are pseudocoelomate.
12. Why are Echinoderms radially symmetrical only in adulthood?
Answer : Their larvae are bilaterally symmetrical, reflecting evolutionary origins.
13. What feature makes Hemichordates a transitional group?
Answer : A partial notochord links them to chordates and non-chordates.
14. How does the tunic in Urochordates function?
Answer : It protects the body and supports attachment in adults.
15. Why are Cyclostomata considered primitive vertebrates?
Answer : They lack jaws and have a cartilaginous skeleton.
16. What adaptation allows Pisces to minimize water resistance?
Answer : Their spindle-shaped body streamlines movement.
17. How do Amphibians differ from Reptiles in skin structure?
Answer : Amphibians have moist, scaleless skin; Reptiles have dry, scaly skin.
18. What makes Aves homeotherms?
Answer : They maintain constant body temperature through metabolic regulation.
19. Why are Mammals distinguished by mammary glands?
Answer : These glands produce milk for nourishing offspring.
20. How does regeneration in starfish aid survival?
Answer : It allows regrowth of lost body parts, enhancing resilience.
Long Questions
1. Explain the benefits of animal classification.
Answer : Classification simplifies studying diverse animals by grouping them based on similarities. It reveals evolutionary relationships and aids accurate identification. It also highlights habitats and adaptations.
2. Describe the characteristics of non-chordates.
Answer : Non-chordates lack a notochord and pharyngeal gill slits. Their nerve cord, if present, is ventral and solid; the heart is dorsal. Examples include Porifera and Arthropoda.
3. What are the key features of chordates?
Answer : Chordates have a notochord, pharyngeal gill slits, and a dorsal hollow nerve cord. Their heart is ventral, distinguishing them from non-chordates. Subphyla include Urochordata and Vertebrata.
4. Discuss the new system of animal classification.
Answer : Whittaker’s five-kingdom system places multicellular animals in Kingdom Animalia. It uses body organization, symmetry, and coelom as criteria. It incorporates evolutionary relationships for systematic study.
5. Explain the grades of body organization in animals.
Answer : Grades range from protoplasmic (unicellular) to cellular (Porifera), cell-tissue (Cnidaria), tissue-organ (Platyhelminthes), and organ-system (humans). Each reflects increasing structural complexity. They aid in classifying animal phyla.
6. What are the types of body symmetry in animals?
Answer : Asymmetrical (sponges), radial (starfish), and bilateral (humans) symmetry define animal body plans. Symmetry reflects lifestyle, with bilateral aiding active movement. It’s a key classification criterion.
7. Describe the role of germ layers in animal classification.
Answer : Germ layers (ectoderm, endoderm, mesoderm) form tissues during development. Diploblastic animals (Cnidaria) have two layers; triploblastic (Annelida) have three. This distinguishes developmental complexity.
8. Explain the concept of body cavity (coelom) in animals.
Answer : The coelom, a cavity formed from mesoderm, classifies animals as eucoelomate (Annelida), acoelomate (Platyhelminthes), or pseudocoelomate (Aschelminthes). It reflects evolutionary advancements. It’s crucial for classification.
9. Discuss the characteristics of Phylum Porifera.
Answer : Porifera (sponges) have cellular-grade organization, asymmetrical bodies, and pores (ostia, oscula). Collar cells aid feeding; spicules support the body. They reproduce asexually and sexually with high regeneration.
10. Describe the features of Phylum Cnidaria.
Answer : Cnidaria (jellyfish, hydra) are radially symmetrical, diploblastic, and mostly marine. Cnidoblast-bearing tentacles capture prey and defend. Examples include corals and sea anemones.
11. Explain the characteristics of Phylum Arthropoda.
Answer : Arthropoda, the largest phylum, has jointed appendages and chitinous exoskeletons. They are triploblastic, eucoelomate, and segmented, thriving in diverse habitats. Examples include crabs and butterflies.
12. Discuss the features of Phylum Mollusca.
Answer : Mollusca includes soft-bodied animals (snails, octopuses) with a shell-secreting mantle. They are triploblastic, eucoelomate, and mostly bilaterally symmetrical. Most are marine; some are terrestrial.
13. Describe the characteristics of Phylum Echinodermata.
Answer : Echinoderms (starfish) are marine, radially symmetrical in adulthood, and triploblastic. Tube feet aid locomotion; calcareous spines form skeletons. They regenerate and are mostly unisexual.
14. Explain why Balanoglossus is a connecting link between non-chordates and chordates.
Answer : Balanoglossus has a partial notochord and pharyngeal gill slits, chordate traits. Its body structure resembles non-chordates, showing dual characteristics. It’s a transitional species in evolution.
15. Discuss the classification of Subphylum Vertebrata.
Answer : Vertebrata includes six classes: Cyclostomata, Pisces, Amphibia, Reptilia, Aves, and Mammalia. They have a vertebral column and cranium. Each class adapts to specific environments.
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