SCIENCE
CHAPTER-2: NUTRITION IN ANIMALS
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Nutrition in Animals
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Nutrition in Animals
INTRODUCTION
Animals get their food from plants, either directly by eating plants or indirectly by eating
animals that eat plants. Some animals eat both plants and animals. Recall that all
organisms including humans require food for growth, repair and functioning of the body.
Animal nutrition includes nutrient requirement, mode of intake of food and its utilisation
in the body
To minimize the entropy, to maintain the body structure and its growth living being
requires continuous input of energy and matter. Primary source for the both is food (or
nutrient). Obtaining such substances is called.
The Process of Nutrition and its examples
Animals have highly evolved digestive mechanism that includes two basic components:
• Alimentary canal: Long, hollow, tubular structure consisting of various organs for
digestion.
• Digestive glands: They secrete enzymes / hormones which help in digestion.
Digestion in animals consists of following steps:
Ingestion: The process of intake of food.
• Digestion: It is the breakdown of large and complex molecules into simpler, smaller and
soluble forms.
• Absorption: Taking up of the digested food through intestinal wall to blood.
• Assimilation: In this process absorbed food is taken by body cells.
• Egestion: The process by which undigested matter is expelled out.
Nutrition- Ways of Taking in Food
• The mode of taking in food by an organism and its utilisation by the body is called
nutrition.
• The process of taking in food inside the body is called ingestion.
• Different animals have different feeding habits; their manner of taking in food also differs.
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Nutrition in Animals
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Animals
Ways of Taking in Food
Frog, chameleon, wall
lizard
Use tongue to catch insects.
Bee, butterfly, humming
bird
Suck nectar from flowers of plants.
Hydra
Uses tentacles with sting cells to kill the prey
and put it in the mouth.
Butterfly
Long feeding tube to suck nectar from flowers
of plants.
Snakes
Swallow the whole animal in one go.
Aquatic animals
Filter tiny food particles floating nearby and
feed upon them.
Digestion in Human Beings
• The breakdown of complex components of food such as carbohydrates, proteins and fats
into simpler substances such as glucose, amino acids and fatty acids respectively is called
digestion.
• Digestion in human beings is carried out in the alimentary canal of the digestive system.
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