1. An adaptation is a set of special traits of an organism that helps it to survive in its environment.
2. There are two main types of adaptations:
(a) Structural adaptations — physical features of an organism that help it survive. Examples: the shape of a bird's beak, the fur on a bear.
(b) Behavioural adaptations — how organisms act or behave in a certain manner to survive. Examples: hibernation and migration.
🦁 Two Types of Adaptations
💡
DID YOU KNOW? A camel's hump stores fat, not water! When food is scarce, the camel uses this stored fat for energy. This is a structural adaptation that helps it survive in the desert.
7.2 Reasons for Adaptations
1. An organism interacts with its environment. This interaction affects the organism's survival in the environment.
2. Organisms have developed different adaptations to survive in different environments:
(a) Cold climates (e.g., polar regions)
(b) Hot and dry environments (e.g., deserts)
(c) Aquatic environments (e.g., oceans, rivers)
🌍 Different Environments & Their Challenges
📝 Key Concept
Organisms develop adaptations through many generations. These traits help them survive in their specific environment.
7.3 Surviving Cold Climates
1. To keep themselves warm in a cold environment, some animals such as polar bears have thick fur with a thick layer of fat beneath their skin, while some birds have an outer layer of compact feathers.
🐻❄️ How Do Animals Survive in the Cold?
2. Other structural adaptations for cold climates include:
(a) Small ears and short limbs — reduce the surface area exposed to cold air, so less heat is lost.
(b) White fur or feathers — provide camouflage in snowy environments, helping animals hide from predators or sneak up on prey.
3. Behavioural adaptations for cold climates include:
(a) Huddling together — penguins huddle to share body warmth.
(b) Migration — some birds fly to warmer regions during winter.
💡
DID YOU KNOW? Emperor penguins can survive temperatures as low as −60°C! They huddle together in groups of hundreds, taking turns being on the warm inside and the cold outside.
📝 Remember
Cold climate adaptations focus on keeping warm and reducing heat loss. Thick fur, fat layers, compact feathers, small ears, and short limbs all help trap body heat.
7.4 Surviving Hot and Dry Environments
1. Animals living in hot and dry environments (deserts) face the challenge of conserving water and staying cool.
🐪 How Do Animals Survive in the Desert?
2. Structural adaptations for hot and dry environments include:
(a) Long legs — keep the body away from the hot ground (e.g., camels).
(b) Light-coloured fur or scales — reflect sunlight to stay cool.
(c) Large ears — release excess body heat (e.g., fennec fox).
3. Behavioural adaptations for hot and dry environments include:
(a) Nocturnal behaviour — being active at night when it is cooler (e.g., desert foxes, snakes).
(b) Burrowing underground — escaping the extreme heat during the day.
💡
DID YOU KNOW? The fennec fox has enormous ears that act like radiators! Blood vessels in the large ears release excess body heat into the air, helping the fox stay cool in the desert.
📝 Remember
Hot and dry climate adaptations focus on conserving water, releasing heat, and avoiding extreme temperatures.
7.5 Aquatic Adaptations
1. Animals that live in water have special adaptations to help them move through water, breathe, and find food.
🐟 How Do Aquatic Animals Survive?
2. Key aquatic adaptations include:
(a) Streamlined bodies — reduce water resistance, allowing animals to swim faster (e.g., fish, dolphins).
(b) Fins and flippers — help with steering and propulsion in water.
(c) Gills — allow fish to extract oxygen dissolved in water.
(d) Webbed feet — act like paddles for swimming (e.g., ducks).
DID YOU KNOW? Penguins are birds that can't fly — but they're incredible swimmers! Their wings have evolved into flippers, and their bodies are streamlined like torpedoes. They can dive to depths of over 500 metres!
📝 Remember
Aquatic adaptations focus on moving through water efficiently, breathing underwater, and staying warm in cold water.
7.6 Plant Adaptations
1. Plants also have special adaptations to survive in different environments:
🌵 How Do Plants Survive in Different Environments?
2. Cactus adaptations (hot and dry environments):
(a) Spines instead of leaves — reduce water loss through transpiration. Spines also protect the plant from being eaten by animals.
(b) Thick, fleshy stem — stores water for long periods when rain is scarce.
(c) Shallow but wide-spreading roots — absorb rainwater quickly from a large area of soil.
3. Mangrove adaptations (coastal, salty water):
(a) Prop roots — grow above the ground to help the tree stand firmly in soft mud and breathe in air.
(b) Salt glands — remove excess salt from the plant's body.
(a) Pitcher-shaped leaves — trap and digest insects to obtain nutrients that are missing from the soil.
(b) The inside of the pitcher is slippery, so insects fall in and cannot escape.
💡
DID YOU KNOW? Some pitcher plants can trap insects as large as small frogs! The Nepenthes rajah, found in Borneo, has pitchers that can hold up to 3.5 litres of fluid — enough to drown a rat!
📝 Remember
Plant adaptations help them survive challenges like water shortage, salty conditions, and nutrient-poor soil. Each adaptation is suited to the plant's specific environment.
📝 Chapter Summary: Key Points
🔑 What You Need to Remember
1. An adaptation is a special trait that helps an organism survive in its environment.
2. There are two types of adaptations:
(a) Structural — physical features (e.g., fur, beak shape, fins)
EXAM TIP: When answering questions about adaptations, always link the adaptation to how it helps the organism survive. For example: "The polar bear has thick fur (adaptation) which keeps its body warm in cold temperatures (how it helps)." Use this format for full marks!
