Trends in Ecology & Evolution
ReviewEcology and the origin of species
Section snippets
Mechanisms of ecological speciation
‘Ecological speciation’ is a concept that unites speciation processes in which reproductive isolation evolves ultimately as a consequence of divergent (including disruptive) selection on traits between environments. ‘Environment’ refers to biotic and abiotic elements of habitat (e.g. climate, resources and physical structure) as well as to interactions with other species (e.g. resource competition, predation, mutualism and various forms of interspecific interference). A diversity of
Tests of ecological speciation
Tests of ecological speciation must consider the alternatives that need to be distinguished (Box 1): speciation by ordinary genetic drift or genetic drift during population bottlenecks 27, 28; speciation by fixation of alternative advantageous genes in populations experiencing similar selection pressures 29; and speciation by polyploidy 30, 31. Speciation by polyploidy can be readily diagnosed genetically, but although it is more common in plants than animals, polyploidy accounts for only 2–4%
Discussion
Speciation is one of the least understood major features of evolution. The main obstacle to progress is the variety of mechanisms that might lead to the evolution of reproductive isolation (Box 1), any one of which can be difficult to rule out in a specific case. The upshot is that it is still difficult to point to even two species in nature and state with confidence the mechanism that produced them. The exceptions are speciation events resulting from polyploidy, because polyploidy leaves a
Acknowledgements
I thank N. Barton, S. Via and other anonymous reviewers for their suggestions. My research is funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).
References (65)
Genetics and the Origin of Species
(1951)- et al.
Laboratory experiments on speciation: what have we learned in 40 years?
Evolution
(1993) A multifactorial genetic investigation of speciation theory using Drosophila melanogaster
Evolution
(1980)- et al.
On the origin of species by sympatric speciation
Nature
(1999) - et al.
Evolutionary branching and sympatric speciation caused by different types of ecological interactions
Am. Nat.
(2000) Rapid origin of sexual isolation and character divergence in a cline
Evolution
(1982)Change of genetic environment and evolution
Complete reproductive isolation between two morphologically similar species of Drosophila
Ecology
(1946)Systematics and the Origin of Species
(1942)Reproductive isolation as a consequence of adaptive divergence in Drosophila pseudoobscura
Evolution
(1989)