Nutrition in Animals
NUTRITION IN ANIMALS
As animals do not have chlorophyll, they can’t prepare their food own. They obtain their food directly or indirectly from plants. Animals may be herbivores, carnivores or omnivores.
In this type of nutrition, animals take in solid food such as fruits, vegetable & meat, etc.
Five steps in the process of holozoic nutrition in animals. are -
NUTRITION IN AMOEBA : Amoeba is a unicellular animal. It eats microscopic plants & animals that float in water.
The complete process of nutrition in amoeba is as follows -
(1) Ingestion : An amoeba ingests food by using its pseudopodia. When a food particles comes near an amoeba, it ingests this food particle by surrounding it with its pseudopodia. The pseudopodia close to form a small cavity called food vacuole.
(2) Digestion : The food is digested in the food vacuole by digestive enzymes.
(3) Absorption : The digested food present in the food vacuole is absorbed directly into the cytoplasm of amoeba by diffusion. The digested food just spreads out from the food vacuole into the cytoplasm of amoeba cell.
(4) Assimilation : Food absorbed by amoeba is used to obtain energy for maintaining life process.
(5) Egestion : When a sufficient amount of undigested food collects inside amoeba, then its cell membrane suddenly ruptures at any place & the undigested food is thrown of the cell.
NUTRITION IN HUMAN
(1) Nutrition in human is holozoic. The food ingested through the mouth passes through a number of organ in our body which constitute the alimentary canal.
(2) The alimentary canal along with digestive glands known as digesttive system.
(3) The digestive system of human consists of following organs -
(i) Mouth : It is a transvers slit & also called opening of alimentary canal. Mouth opens into buccle cavity.
(ii) Buccle cavity : Mouth open into a cavity which con