Evolutionary trap

Cases in which an evolved, and presumably adaptive, trait has suddenly become maladaptive

The term evolutionary trap has retained several definitions associated with different biological disciplines.

## Evolutionary biology

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Within evolutionary biology, this term has been used sporadically to refer to situations in which a pre-existing (and presumably well adapted and successful) trait has become obsolete or maladaptive due to changing biophysical environment and/or competitions, but evolved complexities accumulated by prior adaptations now preclude any effective re-adaptation—as organisms can only modify upon or "patch up" existing traits (which essentially have become inherited "baggage") rather than devolving, removing or "redesigning" a trait (i.e. Dollo's law of irreversibility)—leaving the species hosting the trait struggling to keep up with natural selection and thus vulnerable to competitive disadvantage, extirpation or even extinction.

In the 1991 BBC lecture series Growing Up in the Universe, British evolutionary biologist Richard Dawkins once analogized the concept to that of a mountaineer blindly climbing up (because "evolution has no foresights") while not allowed to turn back downhill, ended up being trapped on one summit and thus cannot go anywhere else higher.

## Ecology

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Within behavioral and ecological sciences, evolutionary traps occur when rapid environmental change triggers organisms to make maladaptive behavioral decisions.[1] While these traps may take place within any type of behavioral context (e.g. mate selection, navigation, nest-site selection), the most empirically and theoretically well-understood type of evolutionary trap is the ecological trap[2] which represents maladaptive habitat selection behavior.

Witherington[3] demonstrates an interesting case of a "navigational trap". Over evolutionary time, hatchling sea turtles have evolved the tendency to migrate toward the light of the moon upon emerging from their sand nests. However, in the modern world, this has resulted in them tending to orient towards bright beach-front lighting, which is a more intense light source than the moon. As a result, the hatchlings migrate up the beach and away from the ocean where they exhaust themselves, desiccate and die either as a result of exhaustion, dehydration or predation.

Habitat selection is an extremely important process in the lifespan of most organisms. That choice affects nearly all of an individual's subsequent choices,[4] so it may not be particularly surprising the type of evolutionary trap with the best empirical support is the ecological trap. Even so, traps may be relatively difficult to detect and so the lack of evidence for other types of evolutionary trap may be a result of the paucity of researchers looking for them coupled with the demanding evidence required to demonstrate their existence.[5]

## See also

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* Coextinction
* Ecological trap
* Evolutionary anachronism
* Evolutionary tradeoff
* Mass extinction
* Perceptual trap

## References

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1. ^ Schlaepfer, M.A.; Runge, M.C.; Sherman, P.W. (2002). "Ecological and evolutionary traps". Trends in Ecology and Evolution. 17 (10): 478–480. doi:10.1016/S0169-5347(02)02580-6.
2. ^ Dwernychuk, L.W.; Boag, D.A. (1972). "Ducks nesting in association with gulls-an ecological trap?". Canadian Journal of Zoology. 50 (5): 559–563. doi:10.1139/z72-076.
3. ^ Witherington, B.E. (1997). "The problem of photopollution for sea turtles and other nocturnal animals". In Clemons, J.R.; Bucholz, R. (eds.). Behavioral approaches to conservation in the wild. Cambridge, UK: Cambridge University Press. pp. 303–328. ISBN 0-521-58054-4.
4. ^ Orians, G.H.; Wittenberger, J.F. (1991). "Spatial and temporal scales in habitat selection". American Naturalist. 137: S29–S49. doi:10.1086/285138.
5. ^ Robertson, B.A.; Hutto, R.L. (2006). "A framework for understanding ecological traps and an evaluation of existing evidence". Ecology. 87 (5): 1075–1085. doi:10.1890/0012-9658(2006)87[1075:AFFUET]2.0.CO;2. ISSN 0012-9658. PMID 16761584.