Nutrition in Animals Class 7 Notes Science Chapter 2 Nutrition in Animals

CBSE Class 7 Science Notes Chapter 2 Nutrition in Animals

Nutrition in Animals with our CBSE Class 7 Science Notes for Chapter 2. These CBSE notes align perfectly with the CBSE syllabus and provide a thorough understanding of the concepts discussed in your NCERT textbook. Ideal for students looking to enhance their knowledge and excel in their studies, these notes cover all key topics detailed in the curriculum.

All animals require food for obtaining energy, growth, repair of damaged parts and functioning of the body. The process of taking food by an animal and its utilisation in the body is called animal nutrition. Plants can prepare their own food by the process of photosynthesis but animals get their food from plants, either directly by eating plants or indirectly by eating other animals that eat plants. Some animals eat both plants and other animals.

Animal nutrition includes nutrient requirements mode of intake of food and its utilisation in the body. The components of food such as carbohydrates are complex substances which cannot be utilised by the body. So, they are broken down into simpler substances. The process of breakdown of complex components of food into simpler substances is called digestion. There are two methods of digesting food, i.e. physical method (including chewing and grinding of food in mouth) and chemical method (addition of digestive juices to the food by the body itself).

Important Topics Covered in Class 7 Science Chapter 2 Nutrition in Animals

1. Types of Nutrition (Autotrophic and Heterotrophic)
2. Human Digestive System
3. Digestive Systems in Various Animals
4. Feeding and Digestion in Simple Organisms
5. Nutritional Disorders
6. Role of Enzymes and Digestive Juices

Revision Notes for CBSE Class 7 Science Chapter 2 Nutrition in Animals 2024-25

Introduction to Animal Nutrition

Nutrient Requirements:

• Animals need a balanced diet containing essential nutrients for their growth, body repair, and overall functioning.
• Just like humans, animals’ bodies require specific nutrients that must be consumed and processed to maintain health.

Modes of Food Intake:

• Animals have different methods of consuming food based on their species and natural habitat. These methods include direct eating of plants, consuming other animals, or a combination of both.
• Examples include herbivores that eat plants, carnivores that eat other animals, and omnivores that consume both plants and animals.

Utilization of Food:

• After ingestion, animals digest and metabolize the food to extract necessary nutrients.
• The process includes digestion (breaking down food into usable components), absorption (uptake of nutrients into the bloodstream), and assimilation (using absorbed nutrients for energy and cellular repair).

Food Components:

• Carbohydrates: Provide energy and are found in foods like grains, fruits, and vegetables.
• Proteins: Essential for muscle and tissue repair; sources include meat, dairy, and certain plants like beans.
• Fats: Needed for energy storage and cell functions; obtained from both plant and animal sources.

Different Ways of Taking Food

Animals have evolved various feeding mechanisms to suit their dietary needs and environmental interactions.

• Feeding Methods:
  • Sucking: Some animals, like bees and hummingbirds, use a specialized mouthpart to suck nectar from flowers, which is their primary food source.
  • Swallowing Whole: Predators like pythons consume their prey whole. They have flexible jaws that allow them to swallow animals larger than their head.
  • Filter Feeding: Certain aquatic animals, such as some fish species, use filter feeding to consume microscopic organisms and particles suspended in water.

Examples of Modes of Feeding

• Hummingbirds: Use their long, specialized beaks to reach into flowers and suck out nectar, their main source of energy.
• Pythons: Capture prey with their jaws, coil around it to suffocate or crush, and then swallow it whole without chewing.
• Aquatic Animals: Creatures like baleen whales and certain fish species filter feed by straining small food particles from the water, using specialized structures like baleen plates or gill rakers.

Digestion in Humans

Digestive System Overview

• Buccal Cavity: The entry point for food where ingestion occurs. Food is chewed here, mixing with saliva which starts the digestion of starch.
• Esophagus (Food Pipe): A muscular tube that transports food from the mouth to the stomach via peristaltic movements (wave-like muscle contractions).
• Stomach: A muscular organ that further breaks down food using stomach acid (hydrochloric acid) and enzymes. Proteins begin their digestion here.
• Small Intestine: The primary site for digestion and nutrient absorption. Digestive juices from the pancreas and bile from the liver aid in breaking down food.
• Large Intestine: Absorbs water and salts from the remaining undigested food matter, converting it into feces.
• Accessory Digestive Glands: Include the salivary glands, liver, and pancreas. These glands produce critical enzymes and bile needed for digestion.

Process of Digestion

• Ingestion: Starts in the buccal cavity where food is taken into the mouth and chewed.
• Digestion:
  • Stomach: Proteins are broken down into smaller peptides by pepsin and acidic environment.
  • Small Intestine: Most of the digestion and absorption occur here. Enzymes from the pancreas and bile from the liver break down carbohydrates, fats, and proteins into simpler molecules like sugars, fatty acids, glycerol, and amino acids.
• Absorption: Nutrients are absorbed through the walls of the small intestine, which are lined with tiny finger-like structures called villi. These increase the surface area for maximum nutrient absorption.
• Assimilation: The absorbed nutrients are transported via the bloodstream to different cells of the body where they are used for various bodily functions like growth, repair, and energy production.
• Egestion: The undigested and unabsorbed food passes into the large intestine where water is absorbed, and the remaining waste material is excreted through the anus as feces.

Teeth and Chewing

• Function of Teeth: Teeth are essential for the mechanical breakdown of food, making it easier to digest. Different types of teeth have specialized roles:
  • Incisors: Sharp, chisel-shaped teeth at the front of the mouth used for cutting and biting into food.
  • Canines: Pointed and situated next to the incisors, canines are used for tearing and ripping food.
  • Premolars and Molars: Located towards the back of the mouth, these teeth have flat surfaces ideal for grinding and crushing food into smaller pieces.
• Dental Health: Maintaining dental health through regular brushing and flossing is important as it prevents food particle accumulation and bacterial growth, which can lead to dental diseases.

Saliva and Digestion

• Role of Saliva: Saliva is not just for moistening food; it contains enzymes that initiate the digestion process.
  • Enzymatic Action: The enzyme amylase present in saliva starts the breakdown of starches into simpler sugars right in the mouth, beginning the digestive process even before food reaches the stomach.
• Digestive Preparation: By lubricating and breaking down food, saliva helps create a food bolus that can easily travel down the esophagus to the stomach.

The Stomach

• Function: The stomach acts as a mixer and grinder of food. It secretes hydrochloric acid and digestive enzymes that break down food, particularly proteins.
• Role of Acids: The hydrochloric acid in the stomach serves multiple purposes:
  • It kills potentially harmful bacteria that enter the stomach with food, enhancing safety.
  • It creates an acidic environment necessary for the enzymes to effectively break down proteins into simpler substances.

The Small Intestine

• Primary Site for Digestion and Absorption: After the initial digestion in the stomach, the food moves into the small intestine, where most of the digestion and nutrient absorption occurs.
• Interaction with Other Organs:
  • Liver: Produces bile stored in the gallbladder before being released into the small intestine. Bile is crucial for the digestion and absorption of fats.
  • Pancreas: Secretes pancreatic juice containing enzymes that further break down carbohydrates, proteins, and fats into simpler molecules that can be easily absorbed.
• Structure for Absorption: The inner walls of the small intestine are lined with villi, small finger-like projections that increase the surface area for absorption. Each villus contains blood vessels which help in transporting the absorbed nutrients to different parts of the body.

Digestion in Grass-Eating Animals

Ruminants

• Definition: Ruminants are herbivores such as cows, deer, and sheep, that digest plant-based food.
• Chewing Cud: These animals initially swallow the grass quickly and then later regurgitate it as cud to chew it thoroughly. This repeated chewing helps break down the food to make the digestion process more efficient.

Cellulose Digestion

• Rumen Function: A key part of a ruminant’s stomach is the rumen. It is a large, fermentation chamber where bacteria break down the tough cellulose into simpler substances that the animal can digest.
• Microbial Assistance: The rumen contains bacteria that are specialized in breaking down cellulose, which is abundant in grass and other plant materials that form the primary diet of these animals.

Feeding and Digestion in Amoeba

Amoeba Feeding

• Mechanism: Amoeba utilizes its pseudopodia, which are temporary, finger-like extensions of its cell surface, to encircle and trap food particles.
• Engulfing Food: Once a food particle is encircled, the amoeba engulfs it, forming a food vacuole, which is a small cavity within the amoeba’s cytoplasm that contains the ingested food.

Digestion in Amoeba

• Digestive Process: Digestive enzymes are secreted into the food vacuole where they break down the food into simpler, absorbable substances.
• Absorption: These simpler substances are then absorbed directly into the cytoplasm of the amoeba, where they are utilized for growth, maintenance, and multiplication.
• Egestion: The undigested residue is expelled from the amoeba by the vacuole, completing the process of digestion.

Tooth Decay and Oral Hygiene

• Problem: Tooth decay occurs when bacteria in the mouth ferment sugars from leftover food, producing acids that erode tooth enamel.
• Prevention: Regular brushing and flossing remove food particles and plaque, reducing the risk of decay. Rinsing the mouth after meals also helps minimize acid buildup.
• Hygiene Tips:
  • Brush teeth at least twice a day.
  • Use dental floss to remove food trapped between teeth.
  • Avoid placing unwashed objects in the mouth to reduce bacteria introduction.

Diarrhea

• Causes: Commonly caused by infections, food poisoning, or indigestion. It leads to frequent, watery stools.
• Risks: Severe cases can lead to dehydration and salt imbalances, which can be fatal, especially in children.
• Treatment:
  • Oral Rehydration Solution (ORS) is recommended to maintain hydration and replace lost salts and sugars.
  • ORS Recipe: Mix boiled and cooled water with a pinch of salt and sugar.
  • Consultation with a healthcare provider is advised if symptoms persist.

NCERT Solutions for Class 7 Science All Chapters

• Chapter 1 Nutrition in Plants
• Chapter 2 Nutrition in Animals
• Chapter 3 Fibre to Fabric
• Chapter 4 Heat
• Chapter 5 Acids, Bases, and Salts
• Chapter 6 Physical and Chemical Changes
• Chapter 7 Weather, Climate, and Adaptations of Animals to Climate
• Chapter 8 Winds, Storms, and Cyclones
• Chapter 9 Soil
• Chapter 10 Respiration in Organisms
• Chapter 11 Transportation in Animals and Plants
  
• Chapter 12 Reproduction in Plants
• Chapter 13 Motion and Time
• Chapter 14 Electric Current and Its Effects
• Chapter 15 Light
• Chapter 16 Water: A Precious Resource
• Chapter 17 Forests: Our Lifeline
• Chapter 18 Wastewater Story

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FAQs on CBSE Class 7 Science Notes Chapter 2 Nutrition in Animals

What is the name of Chapter 2 of Class 7 science?

The name of Chapter 2 in Class 7 Science is Nutrition in Animals. It explores how different animals fulfill their nutritional needs.

What are the types of nutrition in animals Class 7?

In Class 7 Science, the types of nutrition in animals include autotrophic nutrition, where animals produce their food, and heterotrophic nutrition, where animals depend on other organisms for food.

Why are nutrients needed for animals Class 7?

Nutrients are essential for animals as they provide energy, support growth and development, help in repairing tissues, and ensure the proper functioning of bodily processes.

How to Make notes for class 7 Science Chapter 2?

To make notes for Class 7 Science Chapter 2, read the chapter thoroughly, highlight key points, use bullet points for important concepts, and include diagrams for better understanding.

How is nutrition in animals?

Nutrition in animals involves consuming food to obtain nutrients, which are then digested and absorbed to provide energy, maintain health, and support growth.

What is nutrients in animal nutrition?

In animal nutrition, nutrients refer to substances that provide energy, build and repair body tissues, and regulate body processes. These include proteins, fats, carbohydrates, vitamins, and minerals.

What are the 7 nutrients in animals?

The 7 essential nutrients in animals are proteins, carbohydrates, fats, vitamins, minerals, fiber, and water. Each plays a crucial role in maintaining health and supporting vital functions.