Page 16 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

2. Utilisation of Food

Chapter in a Nutshell

v On the basis of food habits, all the animals can be divided into three groups–herbivores,
carnivores and omnivores.
v Plant eating animals are called herbivores. For example, goats, cows, deers, etc.

v Animals that eat other animals are called carnivores. For example, tigers, lions, lizards, etc.
v Animals that eat both plants and other animals are called omnivores. For example, humans,

crows, bears, etc.
v All animals require energy to perform various activities which they obtain from the food
they eat. This energy is obtained after this food is digested and assimilated.

v Nutrition in animals includes intake of food, digestion and its utilisationin the body.
v Food taken by animals is made of complex components such as carbohydrates, which cannot

be absorbed as such and need to be broken down into simpler substances, such as glucose.
This glucose is easily absorbed and provides energy.

v The process of breaking down complex food substances into simpler substances is known as
digestion.

v Different organisms have different ways of taking in food, such as sucking, capturing,
chewing, sponging, brewing, scrapping, grinding, swallowing, etc.
v The mode of nutrition used by humans is holozoic in which complex food is passed through

a special digestive system, where it is broken down into simpler forms so that it can be
absorbed.

v Holozoic mode of nutrition involves ingestion, digestion, absorption, assimilation and
egestion.

v The digestion and absorption of food in human takes place in a canal called alimentary
canal.

v The alimentary canal consists of–buccal cavity, food pipe, stomach, small intestine, large
intestine and anus.
v Salivary glands, liver and pancreas secrete juices that help to breakdown complex food into

simpler forms.
v The first step of digestion, ingestion, involves taking food through the mouth into the buccal

cavity, where the teeth chew the food and break down into small pieces.
v The salivary glands in our mouth secrete saliva that contains an enzyme called salivary

amylase which helps in breaking down of starch into simple sugar (maltose).

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