Adaptive features
| English | Chinese | Pinyin |
|---|---|---|
| adaptive feature | 适应特征 | shì yìng tè zhēng |
| structural | 结构的 | jié gòu de |
| xerophytes | 旱生植物 | hàn shēng zhí wù |
| hydrophytes | 水生植物 | shuǐ shēng zhí wù |
Built to survive
- A polar bear's thick fur, a cactus's spines — living things have features that fit where they live.
- These are adaptive features 适应特征, shaped over time by natural selection.
An adaptive feature is one that helps an organism:
Adaptations improve survival and reproduction.
Adaptations can be structural, behavioural or functional.
All three types help survival.
An inherited feature that improves survival in a habitat is an ______ feature.
Adaptive features are shaped by natural selection.
What an adaptation is
- An adaptive feature is an inherited feature that helps an organism survive and reproduce in its environment.
- It can be structural 结构的 (body parts), behavioural (actions), or functional (how the body works).
People show wide variation in many inherited features
Selection shapes adaptations
On a dark, sooty tree the better-camouflaged moths survive and breed, so the population shifts — adaptive features arise by natural selection.
A cactus's spines help it to:
Spines cut water loss and protect the plant.
Examples
- A cactus has spines (reduce water loss, deter animals) and deep roots (reach water).
- A camel stores fat in its hump and tolerates dehydration — adapted to the desert.
A mutation changes the DNA bases, making a new allele
A plant adapted to dry conditions is called a:
Xerophytes are adapted to dry habitats.
Xerophytes 旱生植物 and hydrophytes 水生植物
- Xerophytes (e.g. cactus) are adapted to dry conditions — small leaves, thick cuticle.
- Hydrophytes are adapted to water — air spaces, stomata on top of floating leaves.
Worked example. A cactus's spines are leaves reduced to reduce water loss, while its thick, fleshy stem stores water and does the photosynthesis — every feature suits a dry desert.
You've got it
- an adaptive feature helps an organism survive and reproduce in its environment
- adaptations can be structural, behavioural or functional
- xerophytes are adapted to dry conditions; hydrophytes to water