Primary 6 Science — Chapter 7: Adaptations in Organisms
Created by Miss Clarissa Ng · www.clartutors.com
A. Types of Adaptations
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
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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.
B. 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.
C. 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. Some animals sleep throughout the cold season by hibernating so that they can conserve energy.
4. Some animals migrate by travelling to other places to avoid the cold winter. They may breed in warmer areas.
5. Some plants have needle-like leaves, while others shed their leaves to reduce water loss.
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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.
D. 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. The fennec fox has large ears which help to release excess body heat into the air.
3. Animals avoid extreme heat by being active at night, hiding in shaded areas, or burrowing underground.
4. Desert snakes burrow themselves underground to escape the extreme surface heat.
5. Desert lizards have light-coloured scales that reflect sunlight and help them stay cool.
6. The camel has hump(s) which store(s) fat that can be used to provide energy when needed.
7. The camel has long legs to keep its body away from the heat of the ground.
8. The camel has thick (or long) eyelashes to protect its eyes from the glaring Sun and sand blown towards its eyes.
9. The camel urinates and sweats very little to conserve water in their bodies.
🦊 Other Desert Adaptations
10. Animals such as fennec fox have large ears to help them lose excess heat.
11. To avoid heat from the Sun, bats hide in shaded areas, while sidewinders burrow themselves in the sand.
12. The cactus has needle-like leaves to reduce water loss through transpiration.
🌵 Desert Plant Adaptations
13. The cactus has swollen stems, which help to store and conserve water.
14. The cactus has shallow roots that extend over a wide area to absorb as much water as possible during rainfall.
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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.
E. Adaptation for Living in the Dark
1. Nocturnal animals, such as owls, have large eyes which help them look for prey in the dark.
📝 Remember
Nocturnal animals are active at night and have adaptations like large eyes to see in the dark.
F. Obtaining Sunlight
1. Trees in thick forests grow very tall in order to compete for sunlight.
2. Some plants climb on other trees using structures like tendrils, hooks and clasping roots to reach for sunlight.
3. Grass spreads over a large area on the ground to obtain as much sunlight as possible.
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DID YOU KNOW? Some climbing plants can grow over 30 metres tall by wrapping around trees! They use the tree as a support structure to reach sunlight in the forest canopy without having to invest energy in building their own thick trunk.
📝 Remember
Plants compete for sunlight by growing tall, climbing on other plants, or spreading over a large area.
G. Floating on Water
1. Floating plants have different ways of floating on water. The water hyacinth has swollen leaf stalks that are filled with air to allow the plants to float on water. The water lettuce has hairy leaves that trap air to allow floating.
2. To prevent leaves from collecting water, the water lily has waxy leaves.
3. Submerged plants have air-filled cavities to help the plants stay upright in water and reach out for sunlight.
📝 Remember
Floating plants use air-filled structures to stay on the water surface, while submerged plants have cavities to remain upright.
H. Breathing Adaptations in Different Environments
1. Fish and tadpoles take in dissolved oxygen by breathing through gills.
2. The mosquito larvae and water stick insect have breathing tubes to take in oxygen directly from air above the water surface.
3. Frogs and toads breathe through their moist skin. They also have lungs to take in oxygen.
4. Animals such as crabs and mudskippers breathe through gills in water. They also have gill chambers, which can hold water containing dissolved oxygen. They can then take in this dissolved oxygen while on land.
5. The great diving beetle and water boatman collect air bubbles, which contain oxygen when they go underwater.
6. Aquatic mammals such as dolphins and whales breathe through their lungs and expel air through their blowholes when they come to the surface.
🫁 How Do Different Organisms Breathe?
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DID YOU KNOW? Whales can hold their breath for over 90 minutes! Sperm whales are champions — they can dive to depths of over 2,000 metres and stay underwater for nearly two hours.
📝 Remember
Different environments require different breathing adaptations. Aquatic organisms use gills or air bubbles, while land animals use lungs or breathing tubes.
I. 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.
J. Movement Adaptations
1. Most aquatic animals such as fish and dolphins have streamlined body shape, which allows faster movement through water.
2. Turtles and penguins have flippers to help them move through water.
3. Ducks and frogs have webbed feet to help them swim.
4. Most birds have well-developed wings covered with feathers to enable them to fly in the air.
5. Most birds have hollow bones to make them lighter and a streamlined body shape to minimise air resistance during flight.
🏃 How Do Organisms Move?
📝 Remember
Movement adaptations help organisms travel efficiently in their environment — whether swimming, flying, or walking.
K. Adaptations for Obtaining Food
1. Birds have different shapes of beaks and claws depending on the types of food they eat:
(a) Sharp, hooked beaks — for tearing meat (e.g., eagles).
(b) Long, thin beaks — for probing flowers for nectar (e.g., hummingbirds).
(c) Short, thick beaks — for cracking seeds (e.g., finches).
2. Some animals camouflage themselves against their surroundings to prevent being seen by their predators or prey.
3. Some animals like wolves hunt in groups to catch larger prey.
4. Some plants grow on poor-nutrient soil. The Venus flytrap and the pitcher plant have special structures to attract and trap insects in order to absorb nutrients.
🍽️ How Do Organisms Obtain Food?
📝 Remember
Adaptations for obtaining food include specialized beaks, camouflage, group hunting, and trapping mechanisms.
L. Adaptations for Deterring Predators
1. Animals such as pufferfish inflate themselves to appear bigger / larger in order to scare away their predators.
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DID YOU KNOW? A pufferfish can inflate itself to three times its normal size in just a few seconds! It swallows water (or air if caught) and expands its stretchy stomach, making it too large for most predators to swallow.
2. Some animals like the buffaloes live in large groups to deter predators from attacking as the predators will feel outnumbered.
🛡️ How Do Animals Protect Themselves?
3. Some animals use camouflage to hide from predators (e.g., chameleons, stick insects).
4. Brightly coloured animals often have warning colours that signal they are poisonous or dangerous (e.g., poison dart frogs).
📝 Remember
Animals use various strategies to avoid being eaten: appearing bigger, living in groups, camouflage, and warning colours.
M. Reproduction Adaptations
1. Peacocks make use of colourful body parts to attract their mates.
2. Some animals attract their mates by performing a courtship ritual or dance.
3. Flowers which are pollinated by birds and insects usually have brightly-coloured petals and contain sweet nectar.
💕 How Do Organisms Attract Mates?
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DID YOU KNOW? The male bird of paradise performs an elaborate dance to attract a female! He spreads his colourful feathers, shakes them rhythmically, and even cleans the ground first — like setting up a stage for his performance.
📝 Remember
Reproduction adaptations help organisms attract mates and ensure their genes are passed on to the next generation.
N. Seed Dispersal Adaptations
Plants have special adaptations to disperse their seeds:
1. Flowers that are pollinated by wind, such as grass flowers, have dull or no petals. They have stamens that hang out in the air so that their pollen can be carried off by wind, and feathery stigmas to catch pollen.
2. Some plants bear juicy / fleshy / fragrant / edible fruit to attract animals to eat the fruit. The animals help carry the seeds to other places.
3. Seeds are usually hard and cannot be digested so that they can be passed out along with the animals' wastes.
4. Some fruits such as the fruit of mimosa have tiny hooks / hair, which can stick onto the bodies of animals and be brought away to another location.
5. Plants that disperse their seeds by wind have wing-like structures (such as angsana) or feathery parachutes (such as dandelions) that help them float in air for a longer period of time.
6. Fruits like the coconut and pong pong have fibrous husks that trap air to stay afloat and allow dispersal by water.
7. The rubber tree and flame of the forest scatter their seeds by splitting / explosive action. As the pods dry up, they eventually split, shooting seeds off in all directions.
🌱 How Do Seeds Travel?
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DID YOU KNOW? Coconuts can float across entire oceans! They have a thick fibrous husk that keeps them buoyant for months, allowing them to wash up on distant shores and grow into new palm trees thousands of kilometres from home.
📝 Remember
Seed dispersal helps plants spread to new areas and avoid competing with the parent plant for resources. Methods include wind, water, animals, and explosive mechanisms.
O. 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.
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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!
🧠 Chapter 7 Concept Map: Adaptation of Organisms to the Environment
🧬 TYPES OF ADAPTATION
🦴 Structural Adaptation Body features — shape, colour, covering e.g. webbed feet, thick fur, camouflage, streamlined body
🏃 Behavioural Adaptation Actions organisms take to survive e.g. migration, hibernation, burrowing, nocturnal activity
🌍 ENVIRONMENTS & ANIMAL ADAPTATIONS
🏜️ Desert Camel — hump stores fat, long eyelashes Kangaroo rat — nocturnal, concentrates urine
💧 Aquatic Duck — webbed feet, waterproof feathers Fish — streamlined body, gills for breathing
