Short & Long Question Answers: Classification of Animals

Short Answer Questions

Q1: What does the term "heterotrophic" mean, and how does it apply to animals?

Ans: Heterotrophic means that an organism cannot produce its own food. Animals are heterotrophic because they depend on plants or other animals for their nutrition. This is one of the common characteristics shared by all animals, regardless of their shape, size, or habitat.

Q2: What are the main features of animals belonging to the phylum Porifera?

Ans: Porifera are mostly found in marine environments, with a few living in freshwater. They are fixed to objects or the ocean floor. Their body has many tiny pores to draw in water and one large pore to expel it. Examples include Sponge and Sycon.

Q3: How do Cnidaria catch their food and move in water?

Ans: Cnidaria have a sac-like body with a single opening called the mouth. This mouth is surrounded by tentacles, which the animal uses for catching food and for swimming. Their body is radially symmetrical, meaning it can be divided into two identical halves along any plane.

Q4: Why are Platyhelminthes considered harmful to humans?

Ans: Platyhelminthes, also called flatworms, are mostly parasitic and live inside the bodies of other animals. The tapeworm, for example, lives in the human intestine, can grow up to six metres in length, and absorbs digested food from the host's body, causing harm.

Q5: Name the four classes of Arthropoda and give one example of each.

Ans: The four classes of Arthropoda are Crustacea (example: Crab), Myriapoda (example: Centipede), Insecta (example: Butterfly), and Arachnida (example: Spider). All arthropods have jointed legs and a body often covered with a tough chitin layer, which provides protection.

Q6: What special features help birds to fly?

Ans: Birds have several features that help them fly. Their body is covered with feathers, and they have wings. Their bones are hollow and light, which reduces body weight. Their jaws form a horny beak without teeth. However, some birds like the Ostrich, Penguin, and Kiwi cannot fly.

Q7: How do fish breathe and move in water?

Ans: Fish are aquatic animals with a streamlined body that is narrow at both ends, helping them move easily through water. They swim using fins and breathe through gills. Their body is covered with scales. Common examples include Rohu, Catla, Mahasheer, Dogfish, and Electric ray fish.

Q8: What are the key differences between Reptilia and Amphibia in terms of skin and breathing?

Ans: Amphibians have slimy, slippery skin and breathe through both lungs and skin. Reptiles, on the other hand, have dry and scaly skin and breathe only through lungs. Both groups mostly lay eggs, but reptiles lay soft-shelled eggs on land, while amphibians lay their eggs in water.

Q9: What is the role of nephridia in Annelida?

Ans: Annelida are segmented worms with a body made up of rings or segments. They have a soft, moist body wall that is used for breathing. Nephridia are special organs found in annelids that are used for excretion, helping remove waste from the body. Earthworm and Leech are common examples.

Q10: How do Mollusca move, and what protects their soft body?

Ans: Mollusca have a soft, unsegmented body that is enclosed in a hard shell, which protects them from predators and harsh conditions. They move using a muscular foot. Common examples of molluscs include Snail, Slug, Pearl oyster, and Octopus, which are found in various aquatic and land habitats.

Long Answer Questions

Q1: Describe the five classes of vertebrates, mentioning two key features and one example of each class.

Ans: Vertebrates are animals with a backbone and are divided into five classes. Pisces (fish) have scales and breathe through gills; example: Rohu. Amphibia can live on land and in water and breathe through lungs and skin; example: Frog. Reptilia have dry, scaly skin and breathe through lungs; example: Lizard. Aves have feathers and hollow bones for flight; example: Pigeon. Mammalia have hair on their body and feed their young ones with milk from mammary glands; example: Cow.

Q2: Explain the characteristics of Class Mammalia. Why are humans included in this class?

Ans: Mammals have several distinct features. Their body is covered with hair, and they have projecting external ears. Most mammals give birth to live young ones, except monotremes. The young ones are fed milk produced by mammary glands in the mother. Mammals usually have a tail and four limbs. Humans are included in this class because they share all these features - they have hair, external ears, give birth to live young, and feed their babies with milk. Examples include Cow, Dog, Elephant, Tiger, and Humans.

Q3: What are invertebrates? Describe any three phyla of invertebrates with their main features and examples.

Ans: Invertebrates are animals that do not have a backbone. They are divided into eight major phyla. Nematoda, or roundworms, have a rounded and unsegmented body and are mostly parasitic; Ascaris lives in the human small intestine. Annelida are segmented worms with a soft body wall used for breathing and nephridia for excretion; examples include Earthworm and Leech. Echinodermata are spiny-skinned marine animals that move using tube feet and have a radially symmetrical body; Starfish and Sea urchin are common examples.

Q4: How are insects and arachnids different from each other? Describe their body structure, legs, and examples in detail.

Ans: Insects and arachnids both belong to the phylum Arthropoda but differ in several ways. Insects have their body divided into three parts: head, thorax, and abdomen. They have three pairs of jointed legs and a pair of antennae on the head. Examples include Ant, Housefly, and Butterfly. Arachnids, on the other hand, have their head and thorax fused together. They have four pairs of jointed legs and completely lack antennae. Examples include Spider, Scorpion, and Ticks. Both groups are covered with a tough chitin layer for protection.

Q5: On what basis are animals broadly classified into two groups? Describe each group and give two examples of each.

Ans: Animals are broadly classified based on the presence or absence of a backbone into two groups: Invertebrates and Vertebrates. Invertebrates are animals that lack a backbone. They are divided into eight major phyla and include a wide variety of animals. Examples are Earthworm and Jellyfish. Vertebrates are animals that have a backbone, also called the vertebral column. They are divided into five classes and are generally more complex in structure. Examples include Frog and Pigeon. Both groups share common features such as being heterotrophic and exhibiting locomotion to find food or shelter.