Question

On what basis plants and animals are put into different categories?

Answer 1

Hint: In order to answer the above question, we need to have knowledge about the biology behind plants and animals. This includes cell biology, the study of variations in movement and locomotion and the difference in the process of nourishment.

Complete answer:
Plants and animals are put in different categories on the basis of the following characteristics:
- Mode of nutrition: Plants are autotrophic as they can prepare their own food by the process of photosynthesis. Whereas animals are heterotrophic as they depend on the outside source for their food.
- Cell composition: Plant cells have cell walls made up of cellulose whereas animal cells do not have any cell wall, only cell membrane is present.
- Locomotion: Plants are immobile as they do not have any locomotory organs. However, they show movement. Animals, on the other hand, have movement as well as locomotion.
- Growth: Plant growth is unrestricted by time, but animal growth is limited to a specific period of time.
- Excretion: Plants expel waste in the form of vapour, gum, sap, resins, and other substances. Urea, uric acid, ammonia, and other waste products are excreted by animals.
- Development of senses: Plants have no or only rudimentary sensory abilities. Animals have a considerably more advanced sensory and neurological system than humans.

Note: Plants show movement as a result of stimuli, which can be in the form of light, touch, etc. They appear as living when they employ their movement against external factors. They have two types of movements: Nastic and Tropic movements. Animals are capable of both movement and complete locomotion.