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Rapid Evolution
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic interactions or opens new environmental niches. Starting with a single ancestor, this process results in the speciation and phenotypic adaptation of an array of species exhibiting different morphological and physiological traits. The prototypical example of adaptive radiation is finch speciation on the Galapagos ("Darwin's finches"), but examples are known from around the world. Characteristics Four features can be used to identify an adaptive radiation: #A common ancestry of component species: specifically a ''recent'' ancestry. Note that this is not the same as a monophyly in which ''all'' descendants of a common ancestor are included. #A phenotype-environment correlation: a ''significant'' association between environments and the morp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin's Finches
Darwin's finches (also known as the Galápagos finches) are a group of about 18 species of passerine birds. They are well known for being a classic example of adaptive radiation and for their remarkable diversity in beak form and function. They are often classified as the subfamily Geospizinae or tribe (biology), tribe Geospizini. They belong to the Thraupidae, tanager Family (biology), family and are not closely related to the true finches. The closest known relative of the Galápagos finches is the South American dull-coloured grassquit (''Asemospiza obscura''). They were first collected when Second voyage of HMS Beagle, the second voyage of the ''Beagle'' visited the Galápagos Islands, with Charles Darwin on board as a gentleman naturalist. Apart from the Cocos finch, which is from Cocos Island, the others are found only on the Galápagos Islands. The term "Darwin's finches" was first applied by Percy Lowe in 1936, and popularised in 1947 by David Lack in his book ''Darwin' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rift Valley Lakes
The Rift Valley lakes are a series of lakes in the East African Rift valley that runs through eastern Africa from Ethiopia in the north to Malawi in the south, and includes the African Great Lakes in the south. These include some of the world's oldest lakes, List of lakes by depth, deepest lakes, List of lakes by area, largest lakes by area, and List of lakes by volume, largest lakes by volume. Many are freshwater ecoregions of great biodiversity, while others are soda lake, alkaline "soda lakes" supporting highly specialised organisms. The Rift Valley lakes are well known for the evolution of at least 800 cichlid fish species that live in their waters. More species are expected to be discovered. The World Wide Fund for Nature has designated these lakes as one of its Global 200 priority ecoregions for conservation. Geology Lake Malawi and Lake Tanganyika have formed in the various valleys of the East African Rift zone. Lake Kivu's "still waters ... hide another face: dissolved ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geospiza
''Geospiza'' is a genus of bird in the tanager family Thraupidae. All species in the genus are endemic to the Galápagos Islands. Together with related genera, they are collectively known as Darwin's finches. Although in the past, they were classified in the bunting and American sparrow family Emberizidae, more recent studies have shown they belong in the tanager family. Taxonomy and species list The genus ''Geospiza'' was introduced in 1837 by the English ornithologist John Gould with the large ground finch as the type species. The genus name derives from the two Ancient Greek words (), meaning "earth", and (), a catch-all term for ''finch''-like birds. The member of the genus form part of a group collectively known as Darwin's finches. Although traditionally placed with the buntings and New World sparrows in the family Emberizidae, molecular phylogenetic studies have shown that Darwin's finches are members of the subfamily Coerebinae within the tanager family Thraupidae. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peter And Rosemary Grant
Peter Raymond Grant (born October 26, 1936) and Barbara Rosemary Grant (born October 8, 1936) are a British married couple who are evolutionary biologists at Princeton University. Each currently holds the position of emeritus professor. They are known for their work with Darwin's finches on Daphne Major, one of the Galápagos Islands. Since 1973, the Grants have spent six months of every year capturing, tagging, and taking blood samples from finches on the island. They have worked to show that natural selection can be seen within a single lifetime, or even within a couple of years. Charles Darwin originally thought that natural selection was a long, drawn out process but the Grants have shown that these changes in populations can happen very quickly. In 1994, they were awarded the Leidy Award from the Academy of Natural Sciences of Philadelphia. The Grants were the subject of the book '' The Beak of the Finch: A Story of Evolution in Our Time'' by Jonathan Weiner, which wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatry
In biology, two closely related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter each other. An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation. Such speciation may be a product of reproductive isolation – which prevents hybrid offspring from being viable or able to reproduce, thereby reducing gene flow – that results in genetic divergence. Sympatric speciation may, but need not, arise through secondary contact, which refers to speciation or divergence in allopatry followed by range expansions leading to an area of sympatry. Sympatric species or taxa in secondary contact may or may not interbreed. Types of populations Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medium Ground Finch
The medium ground finch (''Geospiza fortis'') is a species of bird in the family Thraupidae. It is endemic to the Galapagos Islands, Galápagos Islands. Its primary natural habitat is tropical shrubland. One of Darwin's finches, the species was the first which scientists have observed Evolution, evolving in real-time. Many studies and research have been conducted on medium ground finches: there are the most famous studies conducted by Charles Darwin and more recent studies conducted in relation to the changes revolving around the medium ground finches due to natural selection. Due to an increase in urbanization on the Galápagos Islands, droughts and climate change, character displacement, changes in the finch's habitat and range, inbreeding and nesting, parasites, and viruses, medium ground finches have gone through changes. Changes that have been observed are beak size, behavior in feeding, behavior in inbreeding, behaviors in nesting, antibody development and more. The changes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Ground Finch
The large ground finch (''Geospiza magnirostris'') is a species of bird in the genus Geospiza. One of Darwin's finches, it is now placed in the tanager family Thraupidae and was formerly in the Emberizidae. It is the largest species of Darwin's finch. Description The large ground finch weighs about 27-39 g, and its length ranges slightly 15-16 cm. It is the largest species of Darwin's finch both in total size and size of beak. The feather and bill colors vary between males and females. The adult male is mostly black, with slightly browner wings and tail; the cloaca is white-streaked; the eyes are dark brown. It also has blackish legs. The tail is relatively short. An adult female has browner feathers compared to a male, sometimes with yellow-brown or grey outer edges; scaled patterns are found going up the body; most parts of the torso and the head are streaked with brown and pale yellow shades. Beak It has a large beak, having a thick base of lower mandibles and curved cul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanager
The tanagers (singular ) comprise the bird family (biology), family Thraupidae, in the order Passeriformes. The family has a Neotropical distribution and is the second-largest family of birds. It represents about 4% of all avian species and 12% of the Neotropical birds. Traditionally, the family contained around 240 species of mostly brightly colored fruit-eating birds. As more of these birds were studied using modern molecular techniques, it became apparent that the traditional families were not monophyletic. ''Euphonia'' and ''Chlorophonia'', which were once considered part of the tanager family, are now treated as members of the Fringillidae, in their own subfamily (Euphoniinae). Likewise, the genera ''Piranga'' (which includes the scarlet tanager, summer tanager, and western tanager), ''Chlorothraupis'', and ''Habia (bird), Habia'' appear to be members of the family Cardinalidae, and have been reassigned to that family by the American Ornithological Society. Description T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finch
The true finches are small to medium-sized passerine birds in the family Fringillidae. Finches generally have stout conical bills adapted for eating seeds and nuts and often have colourful plumage. They occupy a great range of habitats where they are usually resident and do not migrate. They have a worldwide native distribution except for Australia and the polar regions. The family Fringillidae contains more than two hundred species divided into fifty genera. It includes the canaries, siskins, redpolls, serins, grosbeaks and euphonias, as well as the morphologically divergent Hawaiian honeycreepers. Many birds in other families are also commonly called "finches". These groups include the estrildid finches ( Estrildidae) of the Old World tropics and Australia; some members of the Old World bunting family ( Emberizidae) and the New World sparrow family ( Passerellidae); and the Darwin's finches of the Galapagos islands, now considered members of the tanager family (Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Costa Rica
Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime boundary, maritime border with Ecuador to the south of Cocos Island. It has a population of around five million in a land area of nearly . An estimated people live in the capital and largest city, San José, Costa Rica, San José, with around two million people in the surrounding metropolitan area. The sovereign state is a Presidential system, presidential republic. It has a long-standing and stable Constitution of Costa Rica, constitutional democracy and a highly educated workforce. The country spends roughly 6.9% of its budget (2016) on education, compared to a global average of 4.4%. Its economy, once heavily dependent on agriculture, has diversified to include sectors such as finance, corporate services for foreign companies, pharmaceut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cocos Island
Cocos Island () is a volcanic island in the Pacific Ocean administered by Costa Rica, approximately southwest of the Costa Rican mainland. It constitutes the 11th of the 15 districts of Puntarenas Canton of the Puntarenas Province, Province of Puntarenas. With an area of approximately , the island is roughly rectangular in shape. It is the Extreme points of North America, southernmost point of geopolitical North America if Island#Continental islands, non-continental islands are included, and the only landmass above water on the Cocos Plate, Cocos tectonic plate. The entirety of Cocos Island has been designated a Costa Rican National Parks of Costa Rica, National Park since 1978, and has no permanent inhabitants other than Costa Rican park rangers. As a result, it has been labelled as the world's largest uninhabited tropical island. Surrounded by deep waters with Equatorial Counter Current, counter-currents, Cocos Island is admired by Scuba set, scuba divers for its populations o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
