"Galapagos Finch Evolution" 6 posts Sort by created date Sort by defined ordering View as a grid View as a list
Offers an evolutionary history of Darwin's finches since their origin almost 3 million years ago. By continuously tracking finch populations over a period of four decades, this title uncovers the causes and consequences of significant events leading to evolutionary changes in species.
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Gabriela Hamerlinck onto Galapagos Finch Evolution @ 10:15 am on 26 Feb 2016
All data files from Grant and Grant 2014.
Gabriela Hamerlinck onto Galapagos Finch Evolution @ 10:14 am on 26 Feb 2016
Abstract: Introgressive hybridization, i.e. hybridization with backcrossing, can lead to the fusion of two species, but it can also lead to evolution of a new trajectory through an enhancement of genetic variation in a new or changed ecological environment. On Daphne Major Island in the Galápagos archipelago, ~1–2% of Geospiza fortis finches breed with the resident G. scandens and with the rare immigrant species G. fuliginosa in each breeding season. Previous research has demonstrated morphological convergence of G. fortis and G. scandens over a 30-year period as a result of bidirectional introgression. Here we examine the role of hybridization with G. fuliginosa in the evolutionary trajectory of G. fortis. Geospiza fuliginosa (~12 g) is smaller and has a more pointed beak than G. fortis (~17 g). Genetic variation of the G. fortis population was increased by receiving genes more frequently from G. fuliginosa than from G. scandens (~21 g). A severe drought in 2003–2005 resulted in heavy and selective mortality of G. fortis with large beaks, and they became almost indistinguishable morphologically from G. fuliginosa. This was followed by continuing hybridization, a further decrease in beak size and a potential morphological fusion of the two species under entirely natural conditions.
All data files from Grant and Grant 2015.
These two activities support the film The Origin of Species: The Beak of the Finch. They provide students with the opportunity to analyze data collected by Princeton University evolutionary biologists Peter and Rosemary Grant.
Gabriela Hamerlinck onto Galapagos Finch Evolution @ 10:13 am on 26 Feb 2016
Four decades of research on finch species that live only on the Galápagos Islands illuminate how species form and multiply.
Gabriela Hamerlinck onto Galapagos Finch Evolution @ 10:12 am on 26 Feb 2016