Nutrition in Animals Class 7 Questions with Answers for NCERT Science

What Is Nutrition and Why Is It Important for Animals?

Nutrition is the process by which living organisms obtain food and use it for energy, growth, and repair. Animals require nutrition to carry out daily activities, maintain body functions, and grow. Without proper nutrition, animals cannot survive or stay healthy.

Animals get their nutrition by consuming different types of food depending on their species. This food provides nutrients like carbohydrates, proteins, fats, vitamins, and minerals essential for life.

Key Points

• Nutrition provides energy for movement and body processes
• Helps in growth and repairing damaged tissues
• Supports reproduction and overall health

Understanding nutrition helps us learn how animals adapt to their environment and meet their energy needs.

Types of Nutrition in Animals Explained for Class 7

Animals show different types of nutrition based on what and how they eat:

• Heterotrophic Nutrition: Animals cannot make their own food and depend on plants or other animals.
• Herbivores: Eat only plants (e.g., cow, deer).
• Carnivores: Eat only other animals (e.g., lion, tiger).
• Omnivores: Eat both plants and animals (e.g., humans, bears).
• Parasites: Live on or inside other animals and feed on them (e.g., leeches).
• Saprotrophs: Feed on dead and decaying matter (e.g., some insects).

Each type of nutrition suits the animal’s habitat and survival needs.

How Do Different Animals Digest Their Food?

Digestion is the process of breaking down food into smaller molecules that animals can absorb and use. Different animals have different digestive systems:

• Ruminants (e.g., cow, deer): Have a four-chambered stomach to digest tough plant material like grass.
• Non-ruminants (e.g., dog, human): Have a single-chambered stomach.
• Carnivores: Have sharp teeth and short intestines to digest meat quickly.
• Herbivores: Have flat teeth and longer intestines to digest fibrous plants.

Example: Cow’s Digestion

Cows swallow food quickly, then regurgitate and chew it again (cud chewing). Their stomach chambers help break down cellulose in grass using microbes.

Formula for Energy from Food

Energy released = Amount of food eaten × Energy content per gram

This energy fuels all body activities.

How Do Animals Obtain Food? Feeding Mechanisms

Animals have developed various ways to obtain food based on their environment and type of nutrition:

• Hunting: Carnivores catch prey using speed and strength.
• Grazing: Herbivores feed on grass and leaves.
• Filter Feeding: Some aquatic animals filter tiny food particles from water.
• Parasitism: Parasites attach to hosts and absorb nutrients.

Example: Spider’s Feeding

Spiders inject digestive juices into prey to liquefy it and then suck the liquid food.

Worked Example

If a lion eats 5 kg of meat containing 2500 kcal per kg, total energy intake = $5 \times 2500 = 12500$ kcal.

Role of Teeth and Digestive Organs in Animal Nutrition

Teeth and digestive organs are specially adapted in animals to help in nutrition:

• Teeth:
• Carnivores have sharp, pointed teeth for tearing flesh.
• Herbivores have flat molars for grinding plants.
• Omnivores have a combination of sharp and flat teeth.

• Digestive Organs:
• Mouth: Begins mechanical digestion.
• Stomach: Breaks down food chemically.
• Intestines: Absorb nutrients into the blood.

Comparison Table of Teeth Types

These adaptations ensure animals efficiently extract nutrients from their food.

Common NCERT Nutrition in Animals Class 7 Questions with Answers

Here are some important questions from the NCERT chapter on nutrition in animals with answers to help you prepare:

1. What is heterotrophic nutrition?

• Animals that cannot make their own food and depend on plants or animals.

2. Name the type of nutrition in cows.

• Herbivorous nutrition.

3. How do carnivores digest their food?

• They have sharp teeth and a short digestive system to digest meat.

4. What is the role of saliva in digestion?

• Saliva contains enzymes that start breaking down food in the mouth.

5. Explain the difference between herbivores and carnivores.

• Herbivores eat plants; carnivores eat other animals.

Practicing such questions improves understanding and exam readiness.