Adaptive features Cambridge IGCSE Biology revision
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In plain words
A cactus stores water and has spines instead of leaves. A polar bear has thick fur and a layer of fat. Each has inherited features that help it survive where it lives. Those are adaptive features.
Three things to know
- An adaptive feature is an inherited feature that helps an organism to survive and reproduce in its environment.
- Xerophytes are plants adapted to dry places: thick waxy cuticle, small or needle-like leaves, sunken stomata, deep or wide roots, swollen stems that store water. All of these reduce water loss or increase water uptake.
- Hydrophytes are plants adapted to live in water: large air spaces to float, stomata on the upper surface of floating leaves, little or no cuticle.
Tips and tricks
- Say how each feature helps: "small leaves give a smaller surface area, so less water is lost by transpiration".
- Adaptive features are inherited. A suntan or big muscles don't count.
It lands in your notebook with its questions as flashcards.
Adaptive features: 5 questions and answers
These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.
What is an adaptive feature?
It also helps the organism to reproduce.
What is a xerophyte?
Cacti are xerophytes.
How does a thick waxy cuticle help a desert plant?
Wax is waterproof.
Why do water plants have large air spaces in their leaves?
Floating keeps the leaves in the light.
Why do cacti have spines instead of broad leaves?
Spines also keep animals from eating them.
Quiz
5 questions
Tap an answer and you’ll see straight away whether it’s right, and why.
Worksheet
3 questions, 7 marks. Write your answers on paper, then check them.
Adaptive features
Cambridge IGCSE Biology 0610 · 7 marks · papermunch.org
Name ______________________________ Date ______________
State what is meant by an adaptive feature.[2]
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An inherited feature that helps an organism to survive and reproduce in its environment.
Describe and explain three features of a cactus that help it to survive in a desert.[3]
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Any three, each explained: spines instead of leaves reduce the surface area for water loss; a thick waxy cuticle reduces evaporation; a swollen stem stores water; wide or deep roots collect as much water as possible; sunken stomata trap moist air.
Explain why the stomata of a water lily are on the upper surface of its leaves.[2]
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The lower surface is in the water, so gas exchange with the air can only happen through the upper surface.
Answers: Adaptive features
- 1. An inherited feature that helps an organism to survive and reproduce in its environment.
- 2. Any three, each explained: spines instead of leaves reduce the surface area for water loss; a thick waxy cuticle reduces evaporation; a swollen stem stores water; wide or deep roots collect as much water as possible; sunken stomata trap moist air.
- 3. The lower surface is in the water, so gas exchange with the air can only happen through the upper surface.