Nutrition in Animals – JSS1 Intermediate Science Lesson Note (Second Term)

How animals feed

Unlike plants that make their own food, animals must go out and find what to eat. Because we depend on others for food, we are called Heterotrophs.

Depending on what they like to eat, we group animals into three main types:

1. Herbivores (The Veggie Lovers)

These are animals that eat only plants, grass, and fruits.

• Examples: Goats, cows, sheep, and grasshoppers.
• Tools: They usually have flat, strong teeth for grinding leaves.

2. Carnivores (The Meat Eaters)

These are animals that eat only the flesh of other animals.

• Examples: Lions, hawks, sharks, and dogs.
• Tools: They have sharp teeth (canines) or claws to tear meat.

3. Omnivores (The “Everything” Eaters)

These animals eat both plants and meat.

• Examples: Humans, pigs, and chickens. (Think about it: you eat rice/vegetables and also fish/meat!)

CLASSES OF FOOD

Just like a car needs fuel to move, our bodies need “fuel” from different types of food to stay healthy. We group these into six main classes:

1. Carbohydrates (Energy Givers): These give you the strength to run, play, and study.
   1. Sources: Yam, rice, cassava (garri), bread, and corn.
2. Proteins (Body Builders): These help you grow taller and repair your body when you have a wound.
   1. Sources: Beans, eggs, fish, meat, and milk.
3. Fats and Oils (Energy Stores): They provide extra energy and keep the body warm.
   1. Sources: Butter, palm oil, groundnut oil, and margarine.
4. Vitamins (Protectors): They protect you from falling sick.
   1. Sources: Oranges, carrots, spinach, and bananas.
5. Minerals (Strong Bones/Blood): Things like Calcium make your teeth strong, and Iron makes your blood healthy.
   1. Sources: Salt, milk, and green vegetables.
6. Water: Very important for cooling the body and moving food around.

THE JOURNEY OF FOOD (DIGESTIVE SYSTEM)

When you take a bite of bread, your body cannot use it in that big form. It has to break it down into tiny “liquid” pieces that the blood can carry. This process is called Digestion.

The Main Parts of the Digestive System:

• The Mouth: This is where it starts. Your teeth chew the food, and your spit (saliva) makes it soft and starts breaking it down.
• The Gullet (Oesophagus): A long tube that carries food from your mouth down to your stomach.
• The Stomach: A “bag” where food is mixed with juices to turn it into a thick soup.
• Small Intestine: This is the most important part! This is where the body absorbs the good nutrients into the blood.
• Large Intestine: This is where the body takes back water from the waste.
• The Anus: The exit point where the waste (poop) leaves the body.

BALANCED DIET AND HEALTH

What is a Balanced Diet?

A balanced diet is a meal that contains all six classes of food in the right amount.

• If you eat only rice (Carbohydrate) every day without meat (Protein) or vegetables (Vitamins), your body will become weak and you might fall sick.

Why Digestion Matters

If your digestive system isn’t working well, even if you eat the best food in the world, your body won’t get the energy. That is why we must:

1. Chew our food properly.
2. Drink enough water.
3. Eat fruits and vegetables (fiber) to help us go to the toilet easily.

Class Activity

Let’s play a game! Look at your lunch today. Can you identify the classes of food in it?

• Example: Rice and Beans with Fried Fish.
  1. Rice = Carbohydrate
  2. Beans and Fish = Protein
  3. Oil used for frying = Fats

Revision Questions

1. What is the difference between a Herbivore and a Carnivore?
2. Which class of food helps to repair a cut on your skin?
3. Name the part of the digestive system where nutrients are absorbed into the blood.
4. Why is water considered a class of food?

Homework

Draw a neat diagram of the human digestive system in your notebook and label the Stomach and the Small Intestine.