Chapter 2: Nutrition in Animals - NCERT Solution

Introduction:
In Chapter 2 of the NCERT textbook on Biology, "Nutrition in Animals," the focus is on understanding the process of nutrition in various animals. It explains how different organisms obtain and utilize food to meet their nutritional requirements. This chapter covers topics such as modes of nutrition, digestive system, and the process of digestion in animals.

1. Modes of Nutrition:
- Autotrophic Nutrition: This mode of nutrition involves organisms that can synthesize their own food using sunlight or inorganic compounds. Plants are the primary example of autotrophic nutrition.
- Heterotrophic Nutrition: In this mode, organisms depend on other organisms for their food. It can be further classified into different types:
- Holozoic Nutrition: Animals that consume solid food and digest it internally fall under this category.
- Saprophytic Nutrition: Organisms that obtain nutrients from dead and decaying matter are saprophytes.
- Parasitic Nutrition: Parasites derive their nutrition from living organisms, often causing harm to the host.

2. Digestive System:
- Ingestion: The process of taking in food through the mouth is called ingestion.
- Digestion: It involves breaking down complex food substances into simpler forms for absorption.
- Absorption: The process by which digested food is absorbed into the bloodstream is called absorption.
- Assimilation: Nutrients are utilized by cells for growth, repair, and energy production through assimilation.
- Egestion: The elimination of undigested waste materials from the body is known as egestion.

3. Process of Digestion:
- Digestion in humans: The human digestive system consists of various organs such as the mouth, esophagus, stomach, small intestine, large intestine, and anus. Each organ plays a specific role in the digestion and absorption of food.
- Digestion in other animals: Different animals have varying digestive systems based on their feeding habits. For example, herbivores have adaptations to digest plant material, while carnivores have adaptations for consuming and digesting meat.

Conclusion:
The chapter "Nutrition in Animals" provides a comprehensive understanding of how different organisms obtain and process food to sustain life. It explains the modes of nutrition, the structure and function of the digestive system, and the process of digestion in animals. By studying this chapter, students can gain insights into the diverse ways in which animals obtain and utilize nutrients for their survival and growth.

What is nutrition