Kingdom Animalia
Can you recall? Page No. 29
1. What is the basis for classification?
Answer: The basis for classification includes body organization, symmetry, germ layers, body cavity, and segmentation.
2. Who proposed Five Kingdom classification system?
Answer: Robert H. Whittaker proposed the Five Kingdom classification system.
3. What is the need and importance of classification?
Answer: Classification simplifies studying organisms, reveals evolutionary relationships, and aids in identification and research.
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Which are the larval stages of Porifera?
Answer: The larval stages of Porifera include amphiblastula and parenchymula larvae.
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Information about coral reef and sea fan.
Answer: Coral reefs are calcium carbonate structures built by cnidarians like Diploria (brain coral), supporting marine biodiversity. Sea fans (Gorgonia) are soft corals with fan-like structures, providing habitats in marine ecosystems.
Can you tell? Page No. 32
1. State parasitic adaptations in liverfluke and Ascaris.
Answer: Liver fluke has hooks, suckers, and a cuticle for attachment and protection; Ascaris has a tough cuticle and no circular muscles for survival in the host’s intestine.
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1. What are the merits and demerits of hermaphroditism?
Answer:
Merits: Hermaphroditism allows animals to reproduce without needing a mate, ensuring reproductive success in sparse populations. It increases the chances of successful reproduction as each individual can produce both eggs and sperm.
Demerits: It may lead to reduced genetic diversity due to self-fertilization, which can decrease adaptability to changing environments. Inbreeding depression may also occur, reducing the fitness of offspring.
2. Why are leeches used in Ayurveda?
Answer: Leeches are used in Ayurveda for bloodletting to treat conditions like inflammation and skin disorders due to their anticoagulant saliva.
3. What is the role of earthworms in agriculture? What is vermicompost?
Answer: Earthworms enhance soil fertility by aerating soil and decomposing organic matter. Vermicompost is nutrient-rich compost produced by earthworms from organic waste.
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1. Why is phylum arthropoda considered as most successful phylum?
Answer: Arthropoda is the most successful due to its vast diversity, adaptability, jointed appendages, chitinous exoskeleton, and ability to inhabit diverse environments.
2. What do we mean by parthenogenesis?
Answer: Parthenogenesis is a form of asexual reproduction where offspring develop from unfertilized eggs, seen in some arthropods like honey bees.
3. What do we mean by living fossil?
Answer: A living fossil is a species that has remained largely unchanged for millions of years, e.g., Limulus (king crab).
4. How do bees produce honey?
Answer: Bees collect nectar, process it with enzymes in their stomach, and store it in honeycombs where it dehydrates into honey.
5. What will happen if arthropods do not moult?
Answer: If arthropods do not moult, their rigid exoskeleton prevents growth, leading to restricted development and potential death.
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1. Explain the term metameric segmentation.
Answer: Metameric segmentation is the division of the body into repeated segments, each with similar structures, as seen in Annelida and Arthropoda.
2. Give characteristics of Arthropoda.
Answer:
- Jointed appendages
- Chitinous exoskeleton
- Bilateral symmetry
- Metameric segmentation
- Open circulatory system
- Well-developed nervous system
3. Enlist harmful Arthropods.
Answer:
- Mosquito (vector for diseases)
- Locusta (locust, crop pest)
- Bed bug (sanguivorous parasite)
4. Why do Molluscs have shell?
Answer: Molluscs have shells for protection against predators, environmental hazards, and to support their soft bodies.
Can you tell? Page No. 36
1. Give salient features of Phylum Echinodermata.
Answer:
- Exclusively marine, radially symmetrical with pentamerous symmetry.
- Endoskeleton of calcareous ossicles with spines.
- Water vascular system for locomotion, feeding, and respiration.
- Complete digestive system; respiration via gills or papillae.
- No circulatory or excretory system; high regeneration ability.
2. Hemichordata is the connecting link between non-chordata and chordata. Give reasons.
Answer:
- Non-Chordate Features: Hemichordates, like Balanoglossus, have a soft, vermiform, unsegmented body resembling non-chordates, such as annelids or other worm-like organisms, and lack a true notochord.
- Chordate-Like Features: They possess structures resembling chordate characteristics, including:
- Buccal Diverticulum: A rod-like structure in the proboscis, once thought to be a notochord, showing similarity to chordate anatomy.
- Pharyngeal Gill Slits: These are present in the pharyngeal region, a key chordate feature used for respiration, similar to those in chordates.
- Dorsal Nerve Cord: The nervous system includes a dorsal nerve cord, partially resembling the hollow dorsal nerve cord of chordates.
- Transitional Role: The combination of a simple, open circulatory system and a body plan with chordate-like gill slits and a notochord-like structure positions Hemichordata as an evolutionary bridge between non-chordates and chordates.
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Why Balanoglossus is considered a connecting link between Non-Chordates and Chordates?
Answer: Balanoglossus has non-chordate traits like a vermiform, unsegmented body and chordate-like features such as pharyngeal gill slits and a buccal diverticulum (presumed notochord), making it a transitional form.
Can you tell? Page No. 37
1. Herdmania is called a Chordate. Explain.
Answer: Herdmania is a chordate because it belongs to the subphylum Urochordata, exhibiting chordate features like a notochord in the larval tail, pharyngeal gill slits, and a dorsal nerve cord during the larval stage, though some features are lost in adulthood.
2. Give characteristics of Petromyzon. Comment on its mode of nutrition.
Answer: Characteristics of Petromyzon (Lamprey):
- Jawless, eel-like body with a soft, smooth, scaleless skin containing unicellular mucus glands.
- Circular, sucking mouth without jaws, adapted for attachment to hosts.
- Cranium and vertebral column made of cartilage.
- Median fins present, but paired fins absent.
- Ectoparasitic lifestyle, primarily marine but migrates to freshwater for spawning (anadromous).
- Two-chambered heart (one auricle, one ventricle) with a closed circulatory system.
Respiration through 6–15 pairs of gill slits without operculum. - Unisexual, with external fertilization and indirect development; adults die after spawning.
Mode of Nutrition:
Petromyzon is an ectoparasite. It uses its circular, sucking mouth to attach to the body of host fish. The mouth contains rasping structures that scrape the host’s flesh, allowing the lamprey to feed on blood, body fluids, and tissues of the host. This parasitic feeding mechanism makes it a significant predator of other fish in its ecosystem.
Can you tell? Page No. 38
1. Differentiate between Chondrichthyes and Osteichthyes on the basis of scales and caudal fin.
Answer:
| Feature | Chondrichthyes | Osteichthyes |
|---|---|---|
| Scales | Exoskeleton formed of placoid scales, which are tooth-like with a bony base and enamel covering. Teeth are modified placoid scales. | Exoskeleton formed of cycloid or ctenoid scales, which are thin, flexible, and bony, providing a smoother covering. |
| Caudal Fin | Heterocercal (asymmetrical), with the upper lobe larger than the lower, aiding in lift during swimming. | Homocercal (symmetrical), with two equal lobes, providing balanced propulsion and stability. |
2. What is the lateral line system?
Answer: The lateral line system in Pisces is a sensory organ system with rheoreceptors that detect water currents, aiding in navigation and detecting movement in the surrounding environment.
3. Why is the Piscian heart called a venous heart?
Answer: The Piscian heart is called a venous heart because it contains only deoxygenated blood, as it pumps blood to the gills for oxygenation in a single, closed circulatory system.
Can you tell? Page No. 40
1. Amphibians do not have exoskeleton. Give reason.
Answer: Amphibians lack an exoskeleton because their moist, glandular skin facilitates cutaneous respiration and flexibility, essential for their dual life in water and on land.
2. Why are amphibians and reptilians called poikilotherms?
Answer: Amphibians and reptiles are poikilotherms because their body temperature varies with the external environment, as they lack internal mechanisms to maintain a constant body temperature.
Can you tell? Page No. 41
1. Give adaptations in aves for flying.
Answer:
- Streamlined body to reduce air resistance.
- Forelimbs modified into wings.
- Hollow (pneumatic) bones to reduce weight.
- Air sacs for increased buoyancy and efficient respiration.
- Feathers for lift and insulation.
2. Aves and mammals are homeotherms. Give reason.
Answer: Aves and mammals are homeotherms because they have physiological mechanisms (e.g., metabolism, insulation via feathers or fur) to maintain a constant body temperature regardless of external conditions.
3. How mammals differ from other groups of animals.
Answer:
- Presence of mammary glands for nourishing young.
- Hair or fur as exoskeleton.
- Homeothermic with high metabolic rate.
- Four-chambered heart for efficient circulation.
- Highly developed brain with corpus callosum (in most).
- Mostly viviparous, with some marsupials and oviparous exceptions.
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