Animal Kingdom Module

Q 1. Which of the following developed for the first time in Annelids?

1. Cephalization
2. Development of a true coelom
3. Metameric segmentation
4. Both 2 and 3

Answer – 4, both 2 & 3
Explanation: Cephalization, which is the concentration of nerve tissue at the anterior end of an organism, and metameric segmentation, which is the pision of the body into segments, are two significant evolutionary developments that first developed in Annelids. Animal Kingdom’s courses will teach you more about these biological phenomena and their influence on modern species.

Q 2. What is the most crucial reason for the immense success of arthropods?

1. Chitinous exoskeleton
2. Uricotelic nature
3. Compound eye
4. Multipurpose appendages

Answer – 1, Chitinous Exoskeleton
Explanation: Arthropods have been incredibly successful due to their chitinous exoskeleton. This complex, external skeleton protects them from physical harm and also enables them to hold in moisture and oxygen – two essential components for survival. The exoskeleton also offers protection from predators making these animals very difficult to catch and keep. Furthermore, they usually have multipurpose appendages necessary for movement, feeding, sensing, and reproduction.

Q 3. What is not valid for a generalized mollusk?

1. The body is segmented into the head, visceral mass, and foot.
2. A rasping tongue-like organ – radula present.
3. Mantle cavity with gills
4. Excretory structures — nephridia

Answer – 1, Body segmented into head, visceral mass, and foot.
Explanation: Mollusks do not typically have a segmented body. They have a soft, unsegmented body usually covered by a hard shell.

Q 4. Which of the following is not seen in hemichordates?

1. A tripartite body organization
2. Stomochord
3. Rudimentary notochord
4. Proboscis gland

Answer – 1, A tripartite body organization
Explanation: Hemichordates have a body plan typically consisting of three central regions: the proboscis, collar, and trunk. However, this tripartite body organization differs from the other organisms’ segmentation. The areas in hemichordates are not accurate segments with repeated structures but rather distinct regions specialized for different functions.

Q 5. The body cavity formed by the splitting of the mesoderm is called

1. pseudo-coelom
2. coelom
3. hemocoel
4. blastocoel

Answer – 2, Coelom
Explanation: The body cavity formed by the splitting of the mesoderm is called coelom. Coelom is a fluid-filled space within an animal, lined with cells and separated from the body wall by the mesoderm. It also allows organs like the heart, lungs, and reproductive organs to develop independently and move freely.

Q 6. Choanocytes are found in

1. outer epithelium
2. inner epithelium
3. mesoglea
4. spongocoel

Answer – 2, Inner Epithelium
Explanation: Choanocytes are found in the inner epithelium of sponges.

Q 7. In contrast to other metazoans, coelenterates have

1. nematocysts
2. gemmules
3. radial symmetry
4. polymorphism

Answer – 3, radial symmetry
Explanation: Coelenterates differ from other metazoans in having radial symmetry. Radial symmetry is a characteristic feature of coelenterates (cnidarians), including organisms such as jellyfish, sea anemones, and corals. These animals typically exhibit a radial body plan with body parts arranged around a central axis, allowing them to have multiple planes of symmetry. In contrast, most other metazoans, such as vertebrates and insects, exhibit bilateral symmetry, where only one plane of symmetry pides the body into left and right halves.

Nematocysts are specialized stinging cells found in coelenterates, gemmules are a unique reproductive structure found in certain sponges, and polymorphism refers to the presence of different specialized forms within a single species, which is not unique to coelenterates.

Q 8. Which of the following does not have a medusa stage?

1. jellyfish
2. hydra
3. obelia
4. corals

Answer – 2, hydra
Explanation: Hydra does not have a medusa stage. Hydra is a freshwater polyp in the class Hydrozoa within the phylum Cnidaria. Unlike other members of the Hydrozoa class, such as jellyfish (which have a medusa and polyp stage in their life cycle), Hydra exists only as a polyp throughout its life. It does not undergo metamorphosis into a medusa stage.

On the other hand, jellyfish, obelia, and corals all have a medusa stage as part of their life cycle. The medusa stage is a free-swimming form of the cnidarians characterized by a bell-shaped body with tentacles hanging down.

Q 9. A triploblastic, unsegmented animal with a complete alimentary canal could be a

1. roundworm
2. Planaria
3. liver fluke
4. Hydra

Answer – 4, Hydra
Explanation: Roundworms (phylum Nematoda) are triploblastic, unsegmented animals with a complete alimentary canal. They are often parasitic in nature and have cylindrical, elongated bodies. With a mouth and anus, they have a complete digestive system that allows them to ingest and digest food.

Q 10. Which animal has a modified mantle cavity to expel water with force?

1. snail
2. oyster
3. squid
4. chiton

Answer – 3, Squid
Explanation: Squids have modified mantle cavities that allow them to expel water with force. This jet propulsion helps them move quickly and efficiently in the water.

Q 11. Which one is not a feature of Agnatha?

1. parasites
2. jawless mouth
3. paired fins
4. horny teeth

Answer – 3, paired fins
Explanation: The feature that is not associated with Agnatha is paired fins. Agnatha is a superclass of jawless fish that includes lampreys and hagfish. While Agnatha is characterized by having a jawless mouth, being parasites (in the case of lampreys), and possessing horny teeth, they do not have paired fins. Instead, they have a long, eel-like body shape with a single fin running along their back, which helps with swimming and stability.

Q 12. Which of the following is a characteristic feature of sponges?

1. Tissue level of organization
2. Presence of Ostia
3. Extracellular digestion
4. Indirect development

Answer – 2, Presence of Ostia
Explanation: The characteristic feature of sponges (phylum Porifera) among the options provided is the presence of Ostia. Ostia are tiny pores or openings on the body of a sponge that allows water to enter its central cavity, called the spongocoel. These ostia are responsible for the filtration of water, which is a vital process for sponges to obtain food and oxygen.

Q 13. Which of the following phylum animals are primarily found in marine water but few are in freshwater

1. Annelida
2. Porifera
3. Mollusca
4. Chordata

Answer – 3, Mollusca
Explanation: The phylum of animals mostly found in marine water, but a few also found in freshwater is Mollusca.

Mollusca is a perse phylum that includes snails, clams, squids, and octopuses. While the majority of mollusks inhabit marine environments, some species have adapted to freshwater habitats. Freshwater mollusks include certain species of freshwater snails and bivalves (e.g., freshwater mussels).

Q 14. Which animal has a cylindrical form

1. Physalia
2. Admsia
3. Hydra
4. 2 & 3

Answer – 4, 2 & 3
Explanation: Among the options provided, Hydra and Physalia (commonly referred to as the Portuguese Man of War) possess a cylindrical form. The former is a small freshwater organism of the phylum Cnidaria, featuring a body with tentacles around its mouth. The latter is a colony of specialized zooids, typically found in marine environments, displaying an air-filled bladder that floats on the surface. Beneath the float are Physalia’s extended tentacles.

Q 15. Corals have a skeleton composed of

1. CaCO3
2. CaPO4
3. CaCl2
4. CaSiO2

Answer – 1, CaCO3
Explanation: Corals have a skeleton composed primarily of calcium carbonate (CaCO3 ). Calcium carbonate is deposited by corals in the form of aragonite, a crystalline form of calcium carbonate. The coral polyps secrete this calcium carbonate to form the hard, stony structure of the coral reef. Over time, accumulated layers of calcium carbonate contribute to the growth and formation of coral reefs.