Adaptations

A camel in the Arctic would be miserable — and a polar bear in the Sahara Desert would not last long at all. Every living thing is built for the place it lives in. The special features that help it survive there have a name, and that name is worth a lot of marks in the PSLE Science paper.

Parents: each section has a predict step your child should try before reading on — let them tap through the virtual habitat experiment and explain why an organism survives or struggles. Saying the keyword out loud is how it sticks in memory.

By the end you will be able to name adaptations for the desert, the Arctic, the ocean, and for plants — and use the exact PSLE keyword your marker is looking for. The four big ideas we will master are: what an adaptation is, desert adaptations, cold-climate adaptations, and plant adaptations. Let's go.

What is an adaptation?

Imagine you moved from an air-conditioned flat in Ang Mo Kio to the middle of the Sahara Desert with no supplies. You would be in serious trouble — your body is not built for that environment. A camel, however, thrives there, because it has the right features for that place.

An adaptation is a special feature or behaviour that helps an organism survive in its habitat. Every organism has a set of adaptations that match where it lives. Features that help an animal find food, stay safe from predators, or cope with the climate are all adaptations.

Desert adaptations — the camel and the cactus

The desert is extremely hot during the day, bitterly cold at night, and bone dry. Very little water and food are available. Organisms that live there need special features to deal with the heat and the lack of water.

The camel

The camel is the icon of desert survival, but its most famous feature is often misunderstood. A camel's humps store fat, not water. When food is scarce, the camel breaks down the fat in its humps to release energy. This means it can go for days without eating. Other adaptations include:

• Large, flat feet — spread the camel's weight so it does not sink into soft sand.
• Long, thick eyelashes and closeable nostrils — block blowing sand from the eyes and nose.
• The ability to drink a huge amount of water in one go (up to 135 litres) and store it in its blood plasma — so it can go long periods without drinking.

The cactus

Plants need water to survive, but water is very hard to come by in the desert. The cactus has a brilliant set of adaptations for this:

• A thick, waxy stem that stores water inside — the whole stem is a water tank.
• A spine (instead of a wide leaf) — spines have a very small surface area, so very little water escapes by evaporation, and they also protect the cactus from animals.
• A wide, shallow root system spreading far around the plant — catches rainwater quickly over a large area whenever it does rain.

Cold-climate adaptations — the polar bear

The Arctic is the opposite of the desert: freezing temperatures, strong icy winds, and a landscape of snow and ice. Staying warm and finding food are the biggest challenges here.

The polar bear is superbly adapted to this extreme cold:

• Thick fur and a thick layer of blubber (fat) under the skin — both trap body heat and insulate the polar bear against the freezing air and icy water. The blubber layer can be up to 11 cm thick.
• White fur — camouflages the polar bear against the snow, letting it sneak up on prey like seals without being spotted.
• Large, slightly webbed paws — work as paddles for swimming in Arctic water and spread the bear's weight on ice so it does not fall through.
• Small ears — reduce the surface area of the body that loses heat to the cold air.

Adaptations for getting food and avoiding predators

Not all adaptations are about temperature or water. Many are about finding food and staying safe.

Getting food:

• The eagle's sharp, hooked beak and strong talons are adaptations for catching and tearing apart prey.
• The giraffe's long neck is an adaptation that lets it reach leaves at the tops of tall trees that other animals cannot reach.
• The anteater's long, sticky tongue is an adaptation for reaching deep into ant tunnels.

Avoiding predators:

• The stick insect's stick-like body is an adaptation that makes it look like a twig, hiding it from birds.
• A hedgehog's sharp spines are an adaptation that makes it painful to swallow — most predators leave it alone.
• A chameleon's ability to change colour is an adaptation that makes it blend into its surroundings.

Survive the Habitat — virtual experiment

Pick an organism and drop it into a habitat. Does it survive? Predict first!

🔬

Survive the Habitat

🤔 Predict first: How do a camel's humps help it survive in the desert?

Humps store fat as an energy reserveHumps store water for drinking

Plant adaptations — not just desert and Arctic

Plants cannot move away from harsh conditions, so their adaptations have to be built in. We have already seen the cactus. Here are three more important plant habitats and their adaptations.

Rainforest plants — getting enough light: Rainforest canopy trees block most of the light. Plants on the forest floor have evolved large, broad leaves to catch as much of the available light as possible — their wide surface area is an adaptation for absorbing light in a shaded habitat.

Aquatic plants (like the water hyacinth or lotus):

• Floating leaves — position the leaf at the water surface where sunlight is brightest.
• Air spaces inside the leaf and stem — keep the plant buoyant so it floats rather than sinking.
• Long, flexible stems — grow up through the water from roots in the muddy bottom below.

Windy clifftop or open grassland plants:

• Waxy leaf coating — reduces water loss through evaporation on windy, exposed hillsides.
• Low-growing, cushion-shaped growth form — stays below the wind and reduces the risk of being torn apart.

Watch out — these are easily mixed up

Quick recap

🎯 Mastery check

Answer all 8 — your progress is saved on this device.

1. What is an adaptation?

   Any feature of a living thingA special feature or behaviour that helps an organism survive in its habitatA behaviour that an animal learns from its parents

2. What is stored in a camel's humps?

   Water, for drinking in the desertFat, as an energy reserve when food is scarceAir, to keep the camel cool

3. How does a cactus survive in the desert without much water?

   Its leaves absorb morning dew from the airIts spines reduce water loss and its waxy stem stores waterIts roots grow only near the surface to collect rare rain

4. A polar bear has thick fur and a thick layer of fat under its skin. How do these features help it survive in the Arctic?

   They insulate the bear and keep body heat in, so it stays warm in freezing temperaturesThey make the bear heavier so it can break through ice to catch fishThey camouflage the bear against the snow so prey cannot see it coming

5. A stick insect looks exactly like a brown twig. How does this adaptation help it survive?

   It stores food inside its stick-like bodyPredators cannot easily spot it, so it is less likely to be eatenIt can absorb water through its bark-like skin

6. A water lily has large floating leaves. How does this adaptation help the plant?

   The large leaves absorb sunlight at the water surface where light is strongestThe leaves store rainwater for the plant to use during dry periodsThe leaves trap insects that fall on the water surface

7. A polar bear has white fur. How is this an adaptation for surviving in the Arctic?

   White fur reflects sunlight to keep the bear cool in summerWhite fur camouflages the bear against the snow, helping it sneak up on preyWhite fur traps more heat than dark fur

8. You are choosing a plant for a very dry, sunny windowsill. Which adaptation would be most useful, and why?

   Large, broad leaves to absorb as much light as possibleWaxy leaves and a water-storing stem to reduce water loss and survive dry conditionsFloating leaves and air spaces to stay buoyant

See my score