1.Diet:

(i) Animals can not able to prepare their own food. They get food from plants and other animals.

(ii) The foods an animal eats every day is called diet.

(iii) Most animals need seven types of nutrients in their diet these include carbohydrates, fats, proteins, vitamins, minerals, water and roughage.

(iv) A diet that contains all the nutrients in the correct amount and proportions is called a balanced diet.

2. Energy needs:

(i) Every day, a person uses up energy. This amount of energy depends on age, sex and type of job.

(ii) All food contains some energy.

(iii) If someone eats too much food extra energy will be stored as fat.

(iv) If someone takes a little amount of food then he or she may feel tired due to less amount of energy.

3. Fat and heart diseases:

(i) The kind of fat present in animals is saturated fat, they also contain cholesterol.

(ii) People who eat lots of saturated fat and cholesterol in their diet are prone to several heart diseases.

(iii) This is because fat deposits build up on the inside of arteries, making them stiffer and narrower. If this happens in the coronary arteries supplying the heart muscle with blood, then not enough blood can get through. The heart muscles run short of oxygen and cannot work properly. This is called coronary heart disease.

(iv) Vegetable oils are usually unsaturated fats.
These, and also oils from fish, do not increase the risk of heart disease, so it is sensible to use these instead of animal fats.

(v) People who take in more energy than they use up get fat. Being very fat is called Obesity.

(vi) Obesity is dangerous to health. Obese people are more likely to get heart disease, strokes and, diabetes.

(viii) The extra weight placed on the legs can cause problems with the joints, especially the knees.

4. Starvations and malnutrition:

(i) Malnutrition is caused by not eating a balanced diet.

(ii) One common form of malnutrition is kwashiorkor. This is caused by a lack of protein in the diet.

(iii) It is most common in children between the ages of nine months and two years after they have stopped feeding on breast milk.

(iv) Kwashiorkor is Often caused by poverty because the child's carers do not have any high-protein food to give to the child.

5. Digestion:

(i) The food that is eaten by mammals usually contains some large molecules of protein, carbohydrate and fat. Before these molecules can be absorbed, they must be broken down into small ones. This process is called digestion.

(ii) Large carbohydrate molecules such as polysaccharides have to be broken down into simple sugars (monosaccharides). Proteins are broken down into amino acids. Fats are broken down into fatty acids and glycerol.

6. Teeth:

(i) Teeth help in ingestion and mechanical digestion of food.

(ii) Teeth also helps in bite off pieces of food along with crop, crush, grind them into small pieces.

(iii) The part of the tooth which is embedded in the gum is called the root.

(iv) The part which can be seen is called the crown.

(v) The crown is covered with enamel which is the hardest substance in animal and human beings.

(vi) Most mammals have four kinds of teeth.
Incisors are the sharp-edged, chisel-shaped
teeth at the front of the mouth. They are used for biting off pieces of food.

(vii) Canines are the more pointed teeth at either side of the incisors.

(viii) Premolars and molars are the large teeth towards the back of the mouth. They are used for chewing food.

(ix) In humans, the ones right at the back are sometimes called wisdom teeth. They do not grow until much later in the person's development than the others.

(x) Mammals also differ from other animals in having two sets of teeth.

(xi) The first set is called the milk teeth or deciduous teeth and the second set is permanent teeth.

(xii) Tooth decay and gum problems are common problems caused by bacteria.

7. Alimentary canal:

(i) The alimentary canal is a long tube that runs from the mouth to the anus. It is part of the digestive system.

(ii) The digestive system also includes the liver and the pancreas.

(iii) The wall of the alimentary canal contains muscles, which contract and relax to make food move along. This movement is called peristalsis
(iv) Special muscles can close the tube completely in certain places. They are called sphincter muscles.

(v) To help the food to slide easily through the alimentary canal, it is lubricated With mucus. Mucus is made in goblet cells which occur along the alimentary canal.
(vi) Absorption the movement of small food
molecules and ions through the wall of the
intestine into the blood.

(vii) Egestion the passing out of food that has not been digested or absorbed, like faeces, through the anus.

(viii) Assimilation is the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells.

8. Diarrhoea

(i) Diarrhoea is the loss of watery faeces. It happens when not enough water is absorbed from the faeces.
(ii) it is a dangerous illness. Diarrhoea is the second largest cause of death of young children in the world.

(iii) There are many different causes of diarrhoea. One of these is infection by a bacterium, which causes the disease cholera This bacterium can be spread through water and food that has been contaminated with faeces from an infected person.

Write the name of the different nutrients present in food.

Important Questions on Animal Nutrition

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