Adaptation of Organisms – JSS2 Intermediate Science Lesson Note (Second Term)

Adaptation is a special feature or behaviour that helps a plant or an animal survive in its environment.

• Fish: gills let a fish take in oxygen from water, so it can breathe underwater.
• Camel: a camel can walk for days in the hot desert because its body is built to save water and store fat.
• Without adaptation: an organism struggles to find food, stay safe or reproduce, and may die out.

Behavioural objectives

By the end of the lesson, students should be able to:

1. Define adaptation and state why it is important.
2. Name the three types of adaptation.
3. Explain each type with at least two examples.
4. Classify given examples as structural, behavioural or physiological.
5. Describe simple adaptations of plants to their habitats.

What are the key terms in adaptation?

Four terms are used throughout this topic.

• Organism: any living thing, such as a plant, an animal or a germ.
• Environment: everything around an organism, including air, water, soil, weather and other living things.
• Habitat: the place where an organism lives, such as a pond, a forest or a desert.
• Survive: to stay alive, find food, avoid enemies and produce young.

Why is adaptation important?

Adaptation is important because it fits an organism to the conditions of its habitat.

• Getting food: a giraffe’s long neck helps it reach leaves high on trees.
• Staying safe: colours that match the surroundings help an animal hide from enemies.
• Coping with weather: animals and plants have ways to deal with heat, cold and dryness.
• Reproducing: an organism that survives can produce young, so its kind continues.

Think of dressing for the weather:

• In a cold place, you wear a heavy jacket.
• At the beach, you wear light clothes.
• Animals and plants are born with their own “clothes” and “tools” to fit their homes.

What are the types of adaptation?

There are three types of adaptation: structural, behavioural and physiological.

What is structural adaptation?

Structural adaptation is a physical body part that helps an organism move, eat, hide or breathe.

• It is the part you can see when you look at the organism.
• It is “built in” to the body.

Examples:

1. Gills in fish: they take in oxygen from the water so the fish can breathe.
2. Long neck in giraffes: it helps them reach green leaves at the top of trees.
3. Camouflage: body colour matches the surroundings. A green grasshopper is hard for birds to see in green grass.
4. Webbed feet in ducks: skin between the toes acts like paddles for faster swimming.
5. Camel’s hump: it stores fat, which the camel uses when food is scarce.
6. Thick white fur in polar bears: it keeps the animal warm in very cold places.

What is behavioural adaptation?

Behavioural adaptation is a way an organism acts that helps it survive.

• It describes what the organism does, not what its body looks like.

Examples:

1. Migration: some birds fly long distances to warmer places when winter comes, because they cannot find food in the snow.
2. Hibernation: animals such as bears sleep very deeply in the cold months to save energy when food is scarce.
3. Nocturnal habits: in the hot desert, animals such as rats stay in cool holes by day and come out at night.
4. Living in groups: fish swim in schools and lions live in prides. Groups make it harder for enemies to attack and easier to find food.

What is physiological adaptation?

Physiological adaptation is a way the inside of the body works that helps an organism survive.

• It involves chemical changes or special body functions.
• You cannot see it from the outside.

Examples:

1. Concentrated urine: the kangaroo rat of the desert produces very little, strong urine. This keeps water inside its body.
2. Venom production: some snakes and spiders make venom (poison) in special glands. They use it to kill prey or defend themselves.
3. Temperature regulation: when you get too hot, your body sweats to cool you down. You do not have to think about it.
4. Antibiotic resistance: some bacteria (germs) are not killed by certain medicines. The resistant ones survive and multiply.

How do plants adapt to their habitats?

Plants adapt mainly through structural features that help them get water, light and support.

• Cactus: thick stems store water and spines replace leaves, which reduces water loss in dry places.
• Water lily: broad floating leaves catch sunlight on the water surface.
• Mangrove: stilt roots hold the plant firm in soft, muddy swamps such as those in the Niger Delta.
• Trees that shed leaves in the dry season: losing leaves reduces water loss when water is scarce.

What is the difference between the three types of adaptation?

The three types differ in what part of the organism is involved.

Evaluation

1. Define adaptation.
2. Why is adaptation important for a lion living in the savanna?
3. Is a polar bear’s thick white fur a structural or a behavioural adaptation? Give a reason.
4. Give one example of a behavioural adaptation you have seen in a local animal, such as a dog or a bird.
5. Explain how sweating is an example of physiological adaptation.

Assignment

Choose three animals or plants found around your home or school. For each one, name one adaptation and state whether it is structural, behavioural or physiological. Explain how it helps the organism survive.