Three types of adaptation
Definition
Adaptation
A feature of an organism that increases its chance of surviving and reproducing in its environment.
- Structural adaptations are physical features of the body, such as a polar bear's thick fur and small ears.
- Behavioural adaptations are the ways an organism behaves, such as birds migrating to warmer places in winter.
- Functional adaptations are the way an organism's body works inside, such as a camel making very little, concentrated urine to save water.
Example
A cactus shows more than one type: a thick stem stores water and spines replace leaves (structural), while it opens its stomata mainly at night (functional) to lose less water.
Explaining an adaptation from information
- You are often given a picture or a description and asked to explain how the organism is adapted to its environment.
- Pick out each feature, then say what it does and how that helps the organism survive or reproduce there.
- Tie every point to the conditions given, such as heat, cold or lack of water, rather than giving a general answer.
Example
The large ears of a desert fox have a big surface area to lose heat, which helps it stay cool in the hot desert.
Adaptations and natural selection
- Adaptations build up over many generations through natural selection, as better-suited individuals survive and pass on their alleles.
- The useful variations were already present by chance, and the organisms that had them left more offspring.
Common Mistake
- Do not say an organism developed a feature because it needed or wanted it.
- Adaptations arise by natural selection acting on random variation, not by effort.
Extremophiles
Definition
Extremophile
An organism, often a bacterium, that is adapted to live in a very extreme environment such as high temperature, high pressure or high salt concentration.
- Extremophiles are organisms adapted to very extreme conditions, such as high temperature, high pressure or high salt concentration.
- Many extremophiles are bacteria, for example those living around deep-sea vents where the water is extremely hot.
- Their enzymes and cell structures keep working in conditions that would kill most other organisms.
Self review
- What is an adaptation?
- Name the three types of adaptation and give an example of each.
- How do adaptations arise over time?
- What is an extremophile, and give an example of where one lives.