Evolution of Character Displacement in Darwin's Finches

  title={Evolution of Character Displacement in Darwin's Finches},
  author={Peter R. Grant and Barbara Rosemary Grant},
  pages={224 - 226}
Competitor species can have evolutionary effects on each other that result in ecological character displacement; that is, divergence in resource-exploiting traits such as jaws and beaks. [] Key Result The observed evolutionary response to natural selection was the strongest recorded in 33 years of study, and close to the value predicted from the high heritability of beak size. These findings support the role of competition in models of community assembly, speciation, and adaptive radiations.
Reproductive isolation of sympatric morphs in a population of Darwin's finches
It is demonstrated that the two morphs show strong positive assortative pairing, a pattern that holds over three breeding seasons and during both dry and wet conditions, and provides strong support for the central role of ecology during the early stages of adaptive radiation.
Fission and fusion of Darwin's finches populations
  • B. Grant, P. Grant
  • Biology
    Philosophical Transactions of the Royal Society B: Biological Sciences
  • 2008
It is proposed that introgression has the largest effect on the evolution of interbreeding species after they have diverged in morphology, but before the point is reached when genetic incompatibilities incur a severe fitness cost.
Experimental demonstration of ecological character displacement
This accordion-like dynamic provides direct experimental evidence that competition for resources can cause evolutionary shifts in resource-related characters.
Disruptive selection in a bimodal population of Darwin's finches
Analysis of patterns of selection in the medium ground finch of El Garrapatero, Santa Cruz Island, Galápagos suggests a dynamic tug of war among factors such as selection and assortative mating, which may alternatively promote or constrain divergence during adaptive radiation.
Character Displacement and the Origins of Diversity
The empirical support for Darwin’s principle of divergence of character is examined, specifically that (1) competition promotes divergent trait evolution, (2) the strength of competitively mediated divergent selection increases with increasing phenotypic similarity between competitors, (3) divergence can occur within species, and (4)competitively mediated divergence can trigger speciation.
Evolutionary Dead End in the Galápagos: Divergence of Sexual Signals in the Rarest of Darwin's Finches
Striking differences in mating signals, morphology and genetics between the two remnant populations of Darwin's mangrove finch Camarhynchus heliobates are reported, and it is shown that territorial males exhibited strong discrimination of sexual signals by locality.
Rapid evolution of a native species following invasion by a congener
On small islands in Florida, it is found that the lizard Anolis carolinensis moved to higher perches following invasion by Anolis sagrei and, in response, adaptively evolved larger toepads after only 20 generations, illustrating that interspecific interactions between closely related species can drive evolutionary change on observable time scales.
Ecological and morphological determinants of evolutionary diversification in Darwin's finches and their relatives
Analysis of the evolutionary dynamics of speciation and trait diversification in Thraupidae illustrates how the exploitation of ecological opportunity by contrasting means can produce clades with similarly high diversification rate yet strikingly different degrees of ecological and morphological differentiation.
Darwin's finches and their diet niches: the sympatric coexistence of imperfect generalists
The results together suggest that the ground finches are ‘imperfect generalists’ that use overlapping resources under benign conditions, but then retreat to resources for which they are best adapted during periods of food limitation, which likely promote local and regional coexistence.
A beak size locus in Darwin’s finches facilitated character displacement during a drought
A genome-wide analysis in finches identifies loci associated with parallel size variation in the Galápagos and discovered a genomic region containing the HMGA2 gene that varies systematically among Darwin’s finch species with different beak sizes.


Ecological Character Displacement in Darwin's Finches
Character displacement resulting from interspecific competition has been extremely difficult to demonstrate, but a study of Darwin's ground finches provides strong evidence for character displacement.
Recurrent patterns of natural selection in a population of Darwin's finches
It is shown that in two subsequent periods of moderate to high adult mortality (1980 and 1982), the population was subject to the same selection as before, and beak depth and body weight were commonly under direct selection to increase but, surprisingly, beak width was directly selected to decrease.
Oscillating selection on Darwin's finches
A reversal in the direction of selection following the opposite climatic extreme is documented, and the connection between oscillating selection and fluctuations in food supply is demonstrated.
Unpredictable Evolution in a 30-Year Study of Darwin's Finches
Continuous, long-term studies are needed to detect and interpret rare but important events and nonuniform evolutionary change in Darwin's finches on the Galápagos island of Daphne Major.
Evaluating two causes of character divergence in feeding morphology between tadpoles of two species of spadefoot toads found that, in natural ponds containing both species, S. multiplicata almost always developed into a smaller, round-bodied tadpole with normal sized jaw muscles used for feeding on detritus at the pond bottom (the “omnivore” morph), whereas S. bombifrons almost always developing into a larger tadpole.
Ecological Character Displacement in Adaptive Radiation
The evidence suggests that character displacement occurs frequently in nature, and it probably plays an important role in the evolution of diversity in many adaptive radiations.
Experimental Evidence That Competition Promotes Divergence in Adaptive Radiation
Disproportionately severe competition between similar phenotypes indicates frequency-dependent selection, verifying a crucial element of theory of competition and character divergence and resolving outstanding debates on the ecological causes of diversification and the evolutionary consequences of competitive interactions.
Convergent and divergent character displacement
It is concluded that the evidence for the ecological aspect of character displacement is weak and the principal ideas in the original definition given by Brown & Wilson (1956) are retained.
Ecological character displacement and the study of adaptation.
  • J. Losos
  • Biology
    Proceedings of the National Academy of Sciences of the United States of America
  • 2000
A growing number of studies that have used integrative, multidisciplinary approaches and have demonstrated that ecological character displacement appears to be an important ecological and evolutionary phenomenon are being demonstrated.
  • P. Grant, B. Grant
  • Environmental Science
    Evolution; international journal of organic evolution
  • 1995
The natural colonization of the small Galápagos island Daphne Major by the large ground finch (Geospiza magnirostris), which bred on the island for the first time in the exceptionally wet El Niño year of 1982–1983, and bred in all subsequent years except drought years.