Kingdom Animalia
Short Questions
1. What is the basis for animal classification?
Answer: Animal classification is based on body organization, symmetry, germ layers, body cavity, and segmentation.
2. Who proposed the Five Kingdom classification system?
Answer: Robert H. Whittaker proposed the Five Kingdom classification system.
3. What is the importance of classification in biology?
Answer: Classification simplifies the study of organisms and reveals evolutionary relationships.
4. What is the cell aggregate body plan?
Answer: The cell aggregate body plan involves cells with minimal differentiation, as seen in Porifera.
5. Which phylum exhibits a blind-sac body plan?
Answer: Phylum Cnidaria exhibits a blind-sac body plan.
6. What is metagenesis in Cnidarians?
Answer: Metagenesis is the alternation of polyp and medusa stages in Cnidarians.
7. Why is Ctenophora considered a minor phylum?
Answer: Ctenophora is a minor phylum due to its limited number of species.
8. What are flame cells in Platyhelminthes?
Answer: Flame cells are excretory structures in Platyhelminthes for osmoregulation.
9. What is the significance of the clitellum in Annelida?
Answer: The clitellum in Annelida is a reproductive structure for cocoon formation.
10. Why do Arthropods undergo moulting?
Answer: Arthropods undergo moulting to shed their chitinous exoskeleton for growth.
11. What is the role of the radula in Mollusca?
Answer: The radula in Mollusca is a rasping organ for feeding.
12. What is the water vascular system in Echinodermata?
Answer: The water vascular system in Echinodermata aids in locomotion, feeding, and respiration.
13. Why is Hemichordata a connecting link between non-chordates and chordates?
Hemichordata has a notochord-like buccal diverticulum, linking non-chordates and chordates.
14. What is the notochord in Chordates?
Answer: The notochord is a flexible rod-like structure providing support in Chordates.
15. What is the lateral line system in Pisces?
Answer: The lateral line system in Pisces detects water currents and pressure changes.
Long Questions
1. Explain the criteria used for animal classification.
Answer: Animal classification is based on grades of organization (cellular to organ-system), body symmetry (asymmetrical, radial, or bilateral), and body cavity (acoelomate, pseudocoelomate, or coelomate). Germ layers (diploblastic or triploblastic) and segmentation (segmented or unsegmented) are also critical. These criteria help categorize animals systematically and understand their evolutionary relationships.
2. Describe the characteristics of Phylum Porifera.
Answer: Phylum Porifera includes sponges with asymmetrical, cellular-level organization and a canal system for water circulation. They have a skeleton of spicules or spongin fibers and choanocytes for creating water currents. Reproduction occurs asexually (fragmentation, gemmules) and sexually with internal fertilization and larval stages.
3. What are the features of Phylum Cnidaria?
Answer: Cnidarians are radially symmetrical, diploblastic animals with a blind-sac body plan and gastrovascular cavity. They exhibit polyp and medusa forms, with tentacles bearing cnidoblasts for defense and prey capture. Reproduction includes asexual budding and sexual metagenesis, alternating between polyp and medusa stages.
4. iscuss the significance of metameric segmentation in Annelida.
Answer: Metameric segmentation in Annelida involves the division of the body into repeating segments, each with similar structures. This allows for specialized functions in different segments and enhances locomotion through coordinated muscle contractions. It also supports organ-system complexity, marking an evolutionary advancement.
5. Why is Phylum Arthropoda considered the most successful phylum?
Answer: Phylum Arthropoda is the most successful due to its diverse adaptations, including a chitinous exoskeleton and jointed appendages for mobility. Their open circulatory system, varied respiratory organs, and reproductive strategies (e.g., metamorphosis, parthenogenesis) enable them to thrive in diverse habitats. Their economic importance, like honey production, further highlights their success.
6. Explain the role of the water vascular system in Echinodermata.
Answer: The water vascular system in Echinodermata is a hydraulic network that facilitates locomotion, food capture, and respiration. Water enters through the madreporite and moves through canals to tube feet, which extend and contract for movement. This system is unique to Echinoderms, supporting their benthic lifestyle.
7. Describe the characteristics of Phylum Mollusca.
Answer: Molluscs are soft-bodied, bilaterally symmetrical (some asymmetrical), triploblastic, and coelomate with a tube-within-tube body plan. Their body consists of a head, foot, and visceral mass, with a mantle secreting a calcareous shell. They have a complete digestive system with a radula, open circulation (except in some), and economic importance (e.g., pearls).
8. What are the key features of Phylum Chordata?
Answer: Phylum Chordata is characterized by a notochord, dorsal hollow nerve cord, pharyngeal gill slits, and ventral heart at some stage. It includes subphyla Urochordata, Cephalochordata, and Vertebrata, with the notochord replaced by a vertebral column in vertebrates. These features distinguish chordates from non-chordates and support complex body functions.
9. Differentiate between Chondrichthyes and Osteichthyes.
Answer: Chondrichthyes have cartilaginous skeletons, placoid scales, and heterocercal tails, with no air bladder, requiring constant swimming. Osteichthyes possess bony skeletons, cycloid/ctenoid scales, and homocercal tails, with an air bladder for buoyancy. Chondrichthyes often have internal fertilization, while Osteichthyes typically have external fertilization.
10. Explain the adaptations in Aves for flight.
Answer: Aves have streamlined bodies and wings (modified forelimbs) for flight, with pneumatic bones reducing weight. Feathers provide lift and insulation, and air sacs enhance respiratory efficiency. The single ovary in females and absence of a urinary bladder further minimize body weight, aiding flight.
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