Question

Explain Nutrition in plants and animals ?

Answer 1

An organism has different modes of nutrition.
They are classified into two major groups on the basis of mode of their taking food
Autotrophic nutrition:
1. In this mode of nutrition, organism synthesizes their own food in their own bodies from simpler inorganic substances. Such organism are known as autotrophs.
2. Autotrophic nutrition is further classified into two types depending on the source of energy used.
Photoautotrophic nutrition:
1. All green plants, certain protists and photosynthesis bacteria have this mode of nutrition.
2. They can directly use the solar energy in the presence of chlorophyll to make their organic food from simpler inorganic substances,i.e., water and carbon dioxide.
3. The green pigment present in them is of trapping the solar energy.
4. This energy is used for the synthesis of food from raw materials- carbon dioxide, water and some minerals. These organisms are known as photoautotrophs.
Chemoautotrophic nutrition or chemosynthesis:
1. Certain bacteria can make organic food from simpler organic substances without using an solar energy.
2. They use energy produced by the breakdown of these inorganic substances.
3. This process is known as chemosynthesis and their mode of nutrition as chemoautotrophic nutrition.
Heterotrophic nutrition:
1. ‘Hetro’ a Greek word means different. In this mode of nutrition, the nutrition are taken from others.
2. All, animals, fungi, many bacteria and some non-organic plants cannot make their own food.
Saprophytic nutrition or saprotrophic nutrition :
1. In this mode of nutrition, organism obtains nutrition from dead decaying organic matter.
2. They secrete digestive juices to the surrounding medium.
3. The enzymes present in these juices convert the non-diffusable food in diffusible form.
4. Then it is absorbed by them through their body surface. For example fungi and bacteria.
5. These organisms are called saprophytes.
Parasitic nutrition
1. This mode of nutrition is to take food from others.
2. The organism that takes food is known as a parasite and the organism from whom food is taken is known as the host.
Holozoic nutrition:
1. The taking in complex organic matter by ingestion
2. The food is then digested and absorbed by the body. For example Amoeba, frog, rabbit, loin and human beings
3. Holozoic nutrition is further of following types.
(a) Herbivorous.
(b) Carnivorous.
(c) Omnivorous.