Darwin's finches: population variation and natural selection.
نویسندگان
چکیده
منابع مشابه
Darwin's finches: population variation and natural selection.
Van Valen's model, which relates morphological variation to ecological variation in an adaptive scheme, was investigated with individually marked and measured Darwin's finches on two adjacent Galápagos islands, Santa Cruz and Daphne Major. Results show that environmental heterogeneity is correlated with large continuous, morphological variation: variation in bill dimensions of Geospiza fortis i...
متن کاملDarwin's finches: Population variation and sympatric speciation.
The classical model of the adaptive radiation of Darwin's finches is one of repeated speciation in allopatry. Evidence presented here suggests that sympatric specification may have contributed to the radiation. On Isla Genovesa Geospiza conirostris displays several features that are consistent with a model of sympatric speciation. Males are polymorphic in song type. Those singing song A have si...
متن کاملIntense Natural Selection in a Population of Darwin's Finches (Geospizinae) in the Galapagos.
Survival of Darwin's finches through a drought on Daphne Major Island was nonrandom. Large birds, especially males with large beaks, survived best because they were able to crack the large and hard seeds that predominated in the drought. Selection intensities, calculated by O'Donald's method, are the highest yet recorded for a vertebrate population.
متن کاملNatural selection and population dynamics.
To what extent, and under which circumstances, are population dynamics influenced by concurrent natural selection? Density dependence and environmental stochasticity are generally expected to subsume any selective modulation of population growth rate, but theoretical considerations point to conditions under which selection can have an appreciable impact on population dynamics. By contrast, empi...
متن کاملDisruptive selection in a bimodal population of Darwin's finches.
A key part of the ecological theory of adaptive radiation is disruptive selection during periods of sympatry. Some insight into this process might be gained by studying populations that are bimodal for dual-context traits, i.e. those showing adaptive divergence and also contributing to reproductive isolation. A population meeting these criteria is the medium ground finch (Geospiza fortis) of El...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Proceedings of the National Academy of Sciences
سال: 1976
ISSN: 0027-8424,1091-6490
DOI: 10.1073/pnas.73.1.257