Test: Classification Of Animals - Class 9 MCQ

The endoderm produced during gastrulation will form the lining of the digestive tract, as well as that of the lungs and thyroid. For animals with three germ layers, after the endoderm and ectoderm have formed, interactions between the two germ layers induce the development of mesoderm.

Animals having identical right and left sides are also known as:

Bilaterally symmetrical

Detailed

Bilateral symmetry is a type of symmetry where an organism can be divided into two equal halves along a single plane. In animals with bilateral symmetry, the right and left sides of their bodies are mirror images of each other. Here is a detailed explanation:

• Bilateral symmetry: Bilateral symmetry is a common characteristic found in many animal species.


• Dividing plane: The dividing plane that separates the organism into two equal halves is called the sagittal plane.


• Mirror images: The right and left sides of an organism with bilateral symmetry are mirror images of each other.


• Examples: Many familiar animals, such as humans, dogs, cats, and birds, exhibit bilateral symmetry.


• Advantages: Bilateral symmetry allows for efficient movement and specialization of body parts.


• Evolutionary adaptation: Bilateral symmetry is believed to have evolved as an adaptation for better coordination and mobility.


• Contrast with other symmetries: Bilateral symmetry is different from radial symmetry, where an organism can be divided into multiple equal parts around a central axis.

Therefore, the correct answer is B: Bilaterally symmetrical.

A pseudocoelomate is an organism with body cavity that is not derived from the mesoderm, as in a true coelom, or body cavity. A pseudocoelomate is also known as a blastocoelomate, or cavity within the embryo.

Multicellular animals are called Metazoa which have been divided into two branches: Parazoa and Eumetazoa.

• In Parazoa, the body of animal is made up of loose cells, have poorly differentiated tissues and have no organ or digestive cavity. E.g sponges.
• In Eumetazoa the cells are properly arranged into tissues and organs.

Hydra and Cnidarians are radially symmetrical - able to asexually divide into identical pie-shaped segments, like a flower pot. Cnidarians also feature tentacles with stinging cells. An organism with radial symmetry has body parts arranged like pieces of a pie around an imaginary central axis.

Classification of Animals According to Habitat
Aristotle
- Aristotle, the ancient Greek philosopher, is credited with classifying animals according to their habitat.
- He categorized animals into three groups based on their habitat: air, water, and land.
- Aristotle's classification system formed the foundation for later systems of taxonomy and classification.
Other Options:
- Socrates: Socrates was a philosopher, but he is not known for classifying animals according to their habitat.
- Linnaeus: Carl Linnaeus, a Swedish botanist and zoologist, is known for developing the modern system of taxonomy, but he did not classify animals based on habitat.
- Plato: Plato was a philosopher, but he did not classify animals based on habitat.
Conclusion:
Aristotle is the philosopher who classified animals according to their habitat, categorizing them into air, water, and land groups. His classification system had a significant impact on the development of taxonomy and classification in the field of biology.

A true coelom arises entirely within the mesoderm germ layer. Animals such as earthworms, snails, insects, starfish, and vertebrates are all eucoelomates. A third group of triploblasts has a body cavity that is derived partly from mesoderm and partly from endoderm tissue. These animals are called pseudocoelomates.

On the basis of origin of mouth, animals have been categorized into : -
Protostomia ( mouth arising from or near the blastopore of gastrula)
Deuterostomia ( mouth arising anteriorly at some distance from the blastopore)

Because there is substance known as chlorophyll which is present only in plants and helps in the process of photosynthesis. That is why the correct option is  'D'.