You have learnt earlier that plants can prepare their own food by the process of photosynthesis with the help of sunlight. But animals cannot. The mode of nutrition in animals is called holozoic nutrition.
Holozoic nutrition:
It is the form of nutrition, in which the animals will consume food in the form of solid.
Animal nutrition covers three major aspects,
  • nutrient requirement
  • mode of intake of food
  • how the food is utilized inside the body.
Nutrient requirement:
There are various types of nutrients available in food such as carbohydrates, proteins, fats and vitamins. These are the components of food that are necessary to provide energy for the organism to survive. Animals consume the food and obtain the nutrients in different ways.
Mode of intake of food:
Nutrition in animals is a complex process involving ingestion, digestion, absorption and assimilation.
Food is taken into the body through the mouth. The process of taking food into the body is called ingestion.
The mode of ingestion in different organisms:
AnimalMode of feeding
Snakesswallow their food
Honey beessucks nectar from plants
dogchew their food using mouth
Eaglecapture their food using beaks
infants of humansucks milk using mouth
Ingestion in human:
We chew the food with the teeth and break it down mechanically, into small pieces. Each tooth is rooted in separate pockets in the gums. There are four different types of teeth, molar, premolar, canine and incisor.
types of teeth.PNG 
The tongue is a muscular organ which is tied to mouth at one end and is free at the other end. Tongue has many taste buds which helps in identifying the taste of the food.
It is also helpful in the process of ingestion. The position of some of the taste buds of tongue are given below: