02. Nutrition in Animals Class 7 Science NCERT Notes for Chapter 2 CBSE

Welcome to Nutrition in Animals Class 7 Science NCERT Notes for Chapter 2 CBSE.

Exam Notes on “Nutrition in Animals” for 7th Class Students

Introduction

In this chapter, we will explore the fascinating world of animal nutrition. Just like plants, animals require food for various purposes, including growth, repair, and maintaining bodily functions. However, unlike plants, animals cannot produce their own food through photosynthesis. Instead, they obtain their food from plants or other animals. Let’s delve into the details of animal nutrition.

Components of Food

Before we proceed, let’s recall the components of food that you learned about in Class VI:

1. Carbohydrates: Carbohydrates are one of the essential nutrients in food, providing energy to the body. They include sugars, starches, and fibers.
2. Proteins: Proteins are the building blocks of the body, used for growth and repair. They are made up of amino acids.
3. Fats: Fats, also known as lipids, are another source of energy and are necessary for the absorption of fat-soluble vitamins.
4. Vitamins: Vitamins are organic compounds required in small amounts for various biochemical reactions in the body. They play roles in immunity, vision, and more.
5. Minerals: Minerals are inorganic nutrients that are essential for various bodily functions, such as calcium for strong bones and iron for blood health.
6. Water: Water is vital for life and makes up a significant portion of our body. It is involved in various physiological processes.

Now that we’ve refreshed our memory, let’s explore the modes of feeding in animals.

Different Ways Of Taking Food

Animals have various ways of obtaining their food. Here are some examples:

1. Snail: Snails are herbivores that scrape their food from surfaces.
2. Ant: Ants are omnivores, and they chew their food into smaller pieces for consumption.
3. Eagle: Eagles are carnivorous birds of prey that capture and swallow their prey whole.
4. Humming-bird: Hummingbirds are nectar-feeding birds that siphon nectar from flowers.
5. Lice: Lice are parasites that suck blood from their host.
6. Mosquito: Mosquitoes are also blood-sucking parasites.
7. Butterfly: Butterflies sip nectar from flowers using their long proboscis.
8. House fly: House flies feed by sponging up liquid substances.

Digestion in Humans

Now, let’s focus on how food is digested in the human body. The human digestive system consists of several organs and glands, including:

1. Buccal Cavity: Food ingestion begins in the mouth. Saliva is secreted here, which contains enzymes to start breaking down carbohydrates.
2. Oesophagus: This is the foodpipe that carries food from the mouth to the stomach.
3. Stomach: In the stomach, food mixes with gastric juices, which contain hydrochloric acid and digestive enzymes to digest proteins.
4. Small Intestine: The majority of digestion and nutrient absorption occurs here. The pancreas and liver release digestive juices, and the small intestine has finger-like projections called villi to enhance absorption.
5. Large Intestine: In the large intestine, water and some salts are absorbed, and the remaining waste forms feces.

Bile and Its Role

The liver secretes bile, which is stored in the gallbladder. Bile plays a crucial role in digesting fats. It emulsifies fats, breaking them into smaller droplets for better digestion.

Types of Teeth

Humans have different types of teeth, each with a specific function:

1. Incisors: Incisors are located in the front and are used for biting and cutting food.
2. Canines: Canines are pointed teeth used for piercing and tearing food.
3. Premolars and Molars: These flat teeth are used for chewing and grinding food into smaller pieces for easier digestion.

Chewing and Saliva

Chewing food thoroughly is essential. It not only mechanically breaks down food but also mixes it with saliva. Saliva contains enzymes that start digesting carbohydrates.

Importance of Oral Hygiene

Maintaining good oral hygiene is crucial to prevent tooth decay. Harmful bacteria in the mouth can break down sugars, producing acids that damage teeth. Regular brushing and flossing are essential.

Oral Hygiene Essentials

• Harmful bacteria thrive without proper oral care.
• They break down sugars, causing tooth decay.
• Neglected decay leads to toothache and loss.
• Brush twice, floss, and rinse after meals.
• Avoid sugary treats for healthier teeth.

Absorption and Assimilation

After digestion, nutrients are absorbed into the bloodstream from the small intestine. These absorbed substances are used for growth and maintenance in a process called assimilation.

Egestion

Undigested and unabsorbed waste is eliminated from the body as feces through the anus.

Ruminants

Some animals, like cows and buffaloes, are ruminants. They have a unique digestive system that allows them to digest cellulose, a complex carbohydrate found in plants.

Amoeba’s Nutrition

Even microscopic organisms like amoeba need to feed. They capture and digest food using pseudopodia and food vacuoles.

This concludes our overview of nutrition in animals. Remember to maintain good dietary habits for a healthy and well-functioning body. If you have any questions, feel free to explore the FAQs below.

Keywords and Their Definitions

Keywords and definitions for nutrition in animals class 7 chapter 2.

• Absorption: The process by which nutrients are taken up into the bloodstream after digestion.
• Amino Acid: The basic building block of proteins.
• Amoeba: A microscopic organism that captures and digests food using pseudopodia and food vacuoles.
• Assimilation: The utilization of absorbed nutrients for growth and maintenance in the body.
• Bile: A digestive fluid produced by the liver and stored in the gallbladder, essential for digesting fats.
• Buccal Cavity: The mouth, where food ingestion begins.
• Canine: A type of tooth used for piercing and tearing food.
• Cellulose: A complex carbohydrate found in plant cell walls.
• Digestion: The process of breaking down food into simpler substances for absorption.
• Egestion: The elimination of undigested and unabsorbed waste from the body.
• Fatty Acid: A component of fats that serves as an energy source.
• Food Vacuole: A cellular structure where food is digested in amoeba.
• Gall Bladder: An organ that stores bile produced by the liver.
• Glycerol: A component of fats.
• Incisor: A type of tooth used for biting and cutting food.
• Ingestion: The process of taking in food.
• Liver: An organ that produces bile and plays a role in detoxifying the body.
• Milk Teeth: The first set of teeth in humans, eventually replaced by permanent teeth.
• Molar: A type of tooth used for chewing and grinding food.
• Permanent Teeth: The set of teeth that replace milk teeth and last throughout adulthood.
• Oesophagus: The foodpipe that carries food from the mouth to the stomach.
• Pancreas: An organ that produces digestive enzymes and insulin.
• Premolar: A type of tooth used for chewing and grinding food.
• Pseudopodia: Temporary extensions of the cell membrane used by amoeba for capturing and engulfing food.
• Rumen: A compartment in the stomach of ruminants where food is partially digested.
• Ruminant: An animal with a specialized digestive system for cellulose digestion, such as cows and buffaloes.
• Rumination: The process of regurgitating and re-chewing food in ruminants.
• Salivary Glands: Glands that secrete saliva, which contains enzymes for carbohydrate digestion.
• Villi: Finger-like projections in the small intestine that increase surface area for nutrient absorption.
• Saliva: A fluid produced by salivary glands that aids in the initial digestion of carbohydrates in the mouth.

Frequently Asked Questions (FAQs)

FAQs for nutrition in animals class 7.

Q1: What is the role of bile in digestion?

A1: Bile plays a crucial role in digesting fats. It emulsifies fats, breaking them into smaller droplets for better digestion.

Q2: How do humans and ruminants differ in digestion?

A2: Humans have a simple stomach, while ruminants have a specialized stomach with multiple compartments for cellulose digestion.

Q3: What are the functions of the small intestine?

A3: The small intestine is where most digestion and nutrient absorption occur. It absorbs nutrients into the bloodstream.

Q4: Why is it important to chew food thoroughly?

A4: Chewing food thoroughly not only mechanically breaks it down but also mixes it with saliva, which contains enzymes for carbohydrate digestion.

Q5: What happens to undigested food in the body?

A5: Undigested food is eliminated as feces through the anus.

Q6: How does amoeba capture and digest food?

A6: Amoeba uses pseudopodia, temporary extensions of its cell membrane, to capture and engulf food particles. Digestion occurs in food vacuoles.

Q7: What are milk teeth and permanent teeth?

A7: Milk teeth are the first set of teeth that appear in humans during infancy and are later replaced by permanent teeth, which last throughout adulthood.

Q8: What is the function of the gall bladder?

A8: The gall bladder stores bile produced by the liver and releases it into the small intestine to aid in fat digestion.

Q9: What are salivary glands, and what is their role?

A9: Salivary glands secrete saliva, which contains enzymes for the initial digestion of carbohydrates in the mouth.

Q10: How are absorbed nutrients used in the body?

A10: Absorbed nutrients are used for growth and maintenance in a process called assimilation.

This was the end of nutrition in animals class 7 Science NCERT Notes for Chapter 2 CBSE.

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