A LITTLE LIGHTBULB MOMENT
Evolution, ecology and organismal diversity
Adaptation is fit to environment, not perfection
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Snowshoe feet help in snow, but not on hot pavement.
The idea behind the cue
An adaptation is a trait shaped by natural selection because it increases fitness in a particular environment. It is not universal perfection; every adaptation has tradeoffs and context.
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Short & simple
Snowshoe feet help in snow, but not on hot pavement.
Acronym
ATC — Awkward Turtles Cackle.
Story
A rabbit’s oversized feet spread its weight on powdery snow. The same feet would be awkward in mud, so the trait is useful mainly in that habitat.
Connect the pieces
- A (Awkward) → Adaptive: A trait is favored by natural selection when it increases fitness in a particular environment.
- T (Turtles) → Tradeoff: Adaptations are not perfect; they usually come with costs as well as benefits.
- C (Cackle) → Context: The same trait can be helpful in one habitat and neutral or harmful in another.
- Awkward · Adaptive: A trait is favored by natural selection when it increases fitness in a particular environment.
- Turtles · Tradeoff: Adaptations are not perfect; they usually come with costs as well as benefits.
- Cackle · Context: The same trait can be helpful in one habitat and neutral or harmful in another.
Know the limits
A trait may be adaptive in one habitat and neutral or harmful in another.
Further reading · OpenStax science and mathematics textbooks ↗Check your understanding
What is the best definition of an adaptation?
A. A temporary behavior learned during life and passed to offspring.
B. A trait that works equally well in every environment.
C. A trait favored by natural selection because it increases fitness in a particular environment.
D. Any trait an organism happens to have at birth.
Reveal explanation
A trait favored by natural selection because it increases fitness in a particular environment.
Adaptations arise by natural selection and improve fitness in a specific environment; they are not guaranteed to be universally beneficial.