Ecological speciation

European Holly (Ilex aquifolium). The genus Ilex is an example of ecological speciation.
Gasterosteus aculeatus, a documented case of ecological speciation
Centaurea solstitialis, a candidate species for incipient ecological speciation

Ecological speciation is the process by which ecologically based divergent selection between different environments leads to the creation of reproductive barriers between populations.[1] This is often the result of selection over traits which are genetically correlated to reproductive isolation, thus speciation occurs as a by-product of adaptive divergence.[2][3]

The key difference between ecological speciation and other kinds of speciation, is that it is triggered by divergent natural selection among different ecosystems, as opposed to other kinds of speciation processes, like random genetic drift, or sexual selection. Ecological speciation can occur either in allopatry or in sympatry. The only requirement being that speciation occurs as a result of adaptation to different ecological or micro-ecological conditions.[1]

Examples

Known examples of ecological speciation include three-spined stickleback fishes, distinct species of which emerged as the result to adaptation of different conditions along water depth clines in freshwater lakes.[4] Ancestors of the genus Ilex (holly) became isolated from the remaining Ilex when the Earth mass broke away into Gondwana and Laurasia about 82 million years ago, resulting in a physical separation of the groups (allopatry) and beginning a process of change to adapt to new conditions; over time survivor species of the holly genus adapted to different ecological niches. The invasive weed species Centaurea solstitialis is a candidate to be a case of incipient ecological speciation; in less than 200 years, incipient reproductive isolation appeared as a result to adaptation to different ecological conditions between native and non-native ranges.[5][6]

See also

References

  1. 1 2 Nosil, P. (2012). Ecological Speciation. Oxford: Oxford University Press. p. 280. ISBN 978-0199587117.
  2. ↑ Mayr, E. (1942). Systematics and the origin of species from the viewpoint of a zoologist. New York: Columbia University Press. p. 337. ISBN 0-674-86250-3.
  3. ↑ Mayr, E. (1947). "Ecological factors in speciation.". Evolution 1: 263–288. doi:10.2307/2405327.
  4. ↑ Behm, J. E., A. R. Ives and J. W. Boughman. 2010. "Breakdown in postmating isolation and the collapse of a species pair through hybridization" American Naturalist 175:11–26.
  5. ↑ Montesinos, D., Santiago, G., & Callaway, R. M. (2012). Neo-allopatry and rapid reproductive isolation. The American Naturalist, 180(4), 529–33.
  6. ↑ Graebner, R. C., Callaway, R. M., & Montesinos, D. (2012). Invasive species grows faster, competes better, and shows greater evolution toward increased seed size and growth than exotic non-invasive congeners. Plant Ecology, 213(4), 545–553.
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