Adaptation
In biology, an adaptation is a feature of a living thing that helps it to survive and reproduce in its environment.[1] Adaptations are passed on from parents to offspring, and they may be part of an organism's body or its behaviour.[2] Being adapted to the local environment is one of the features shared by living things.[3]
Examples
The woodpecker was one of Darwin's favourite examples. It has a powerful beak for digging into wood, a long tongue for probing, a stiff tail that braces it against the tree, and short legs with long curved toes for gripping.[4] Many animals are camouflaged, with colours, shapes or behaviour that make them harder for their enemies to see.[4] In humans, hands for grasping, eyes for seeing and legs for moving are all adaptations.[4]
Adaptation and natural selection
Darwin saw adaptation as the key problem that any theory of evolution had to solve.[4] His answer was natural selection. Individuals that leave more offspring than average pass on their features more often, as long as offspring resemble their parents. Over many generations, helpful features spread.[4] Not every detail of an organism is necessarily an adaptation.[4]
Natural selection can work in different ways. Stabilising selection favours the average form. Directional selection shifts a population one way as the environment changes, and diversifying selection favours the extremes.[5] A famous example of directional selection comes from moths. After the Industrial Revolution, dark-coloured moths became more common because they were better camouflaged.[5]
Small steps
Adaptive evolution usually happens through many small changes rather than sudden large ones.[6] One model compares this to focusing a microscope: small adjustments are more likely to improve the picture than big ones. In the same way, a very large mutation has almost no chance of being helpful.[6][6]
Adaptive radiation
Sometimes many species evolve from one ancestor, each adapted to a different way of life. This is called adaptive radiation. The honeycreepers are an example. They have thick beaks for eating seeds, long beaks for drinking nectar, or sword-like beaks for catching insects. Darwin's finches are another example.[7] In Darwin's finches, the beak affects both feeding and song, so adaptation can also help new species to form.[8]
Adaptation in microorganisms
Microorganisms seem to have been the only life on Earth for over 3 billion years. Plants and animals have existed for only about the last 500 million years.[9] In that time, microbes evolved ways of living in every habitat.[9] Some archaea, for example, live in extreme environments such as black smokers, where the water can be hotter than 400 °C.[10]
See also
References
- ↑ Ridley, Mark (2004). Evolution (3rd ed.). Malden, MA: Blackwell Publishing. pp. 5–6. ISBN 1-4051-0345-0.
{{cite book}}:|access-date=requires|url=(help) - ↑ Zedalis, Julianne; Eggebrecht, John (2018). Biology for AP Courses. Houston: OpenStax. p. 747. ISBN 978-1-947172-40-1. Retrieved 2026-10-23.
- ↑ Wessner, David R.; Dupont, Christine; Charles, Trevor C.; Neufeld, Josh D. (2021). Microbiology (3rd ed.). Hoboken, NJ: Wiley. p. 4. ISBN 978-1-119-71581-8. Retrieved 2026-10-23.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Ridley, Mark (2004). Evolution (3rd ed.). Malden, MA: Blackwell Publishing. p. 6. ISBN 1-4051-0345-0.
{{cite book}}:|access-date=requires|url=(help) - ↑ 5.0 5.1 Zedalis, Julianne; Eggebrecht, John (2018). Biology for AP Courses. Houston: OpenStax. p. 787. ISBN 978-1-947172-40-1. Retrieved 2026-10-23.
- ↑ 6.0 6.1 6.2 Ridley, Mark (2004). Evolution (3rd ed.). Malden, MA: Blackwell Publishing. p. 266. ISBN 1-4051-0345-0.
{{cite book}}:|access-date=requires|url=(help) - ↑ Zedalis, Julianne; Eggebrecht, John (2018). Biology for AP Courses. Houston: OpenStax. p. 737. ISBN 978-1-947172-40-1. Retrieved 2026-10-23.
- ↑ Ridley, Mark (2004). Evolution (3rd ed.). Malden, MA: Blackwell Publishing. p. 386. ISBN 1-4051-0345-0.
{{cite book}}:|access-date=requires|url=(help) - ↑ 9.0 9.1 Wessner, David R.; Dupont, Christine; Charles, Trevor C.; Neufeld, Josh D. (2021). Microbiology (3rd ed.). Hoboken, NJ: Wiley. p. 15. ISBN 978-1-119-71581-8. Retrieved 2026-10-23.
- ↑ Wessner, David R.; Dupont, Christine; Charles, Trevor C.; Neufeld, Josh D. (2021). Microbiology (3rd ed.). Hoboken, NJ: Wiley. p. 110. ISBN 978-1-119-71581-8. Retrieved 2026-10-23.