Adaptive radiation essay

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Adaptive radiation essay

Species can go through an adaptive radiation involving a diversification of that speciesin response to having invaded a vacant ecological niche. It is thought the ability to do this, can be attributed to one or more key innovations developed by this species i.

A radiating clade, which is the original ancestral species and descendants, then has opportune to exploit the new resources that often come with this new vacant niche. And perhaps not have to compete with other species present, for the same resources and space.

The role of a key innovation in an adaptive radiation can be thought of as a new feature which increases ecological opportunity Schluter, This ecological opportunity, in turn, can be defined as "the wealth of different resource types under-utilized by species in other taxa" Schluter, These two main ideas, partly make up the "ecological theory".

This theory generally states that the differences in phenotype observed between populations and species, is caused directly by differences in the environment they inhabit and resources consumed Schluter, This essay looks at some examples of adaptive radiations that have seen the arising of several new species from an ancestral group in a relatively short period of time.

Each example attempts to explain how each radiating clade is the result of a key innovation. These examples are well covered in previous literature and this essay instead examines others. Other more unknown examples discussed include diversity of insects that feed on vascular plants, and diversity of weevils.

Firstly, a historical view of some major radiations will be looked at, and what has to be considered before concluding that a key innovation itself has been largely responsible for an adaptive radiation. Another theory, 'the environmental stimulus theory' is examined briefly also, which opposes the key innovation hypothesis.

Some do refute the importance of key innovations in adaptive radiations. Schluter discusses hypotheses concerning the possible causes for adaptive radiations, two are discussed in this essay.

The 'environmental stimulus hypothesis' states the ancestral animal group had always a certain potential to diverge into different groups, given the right conditions.

Adaptive radiation essay

So, following a major facilitating change, such as the removal of a environmental constraint extreme temperatures, low nutrient or oxygen levels. This supposedly would stimulate the divergence of different groups.

The second hypothesis concerns whether or not key innovations are the major instigator of an adaptive radiation. The 'key innovation hypothesis' argues that instead it is the acquiring of a biological feature that allows the divergence of animal groups as aforementioned.

An innovation can be anything from a developmental gene to an external structure specialised limb for example.

Adaptive radiation essay

The certainty that the species was able to invade a new niche, directly because of new key innovations, is debatable. Obviously, other confounding factors must be considered first, to rule out that they themselves have prompted the adaptive radiation.

Simpson suggests two steps are necessary to conclude the key innovation itself is responsible. Firstly, the correlation between the appearance of a key character and diversification must be confirmed.

Secondly, the ecological opportunity gained from the key innovation must be separated from other mechanisms operating at the time.

It was also observed that those without these certain morphological features were contained within clades that were species-poor.

Sari essayah eurovaalit ehdokkaat le premier ministre britannique dissertations, equality diversity and rights essay help remoteness of damages essays pestilence horsemen descriptive essay adaptive radiation essay, percy shelley bridal song analysis essay. ap biology outline: evolution. 1. darwin-wallace theory and its predecessors. 2. modern concepts of natural selection. a. population genetics: hardy-weinberg equilibrium and. Mammalia: Cetacea and Adaptive Radiation Essay When ancestors of cetacean phylogeny switched to piscivory it caused rapid change (Thewissen et al. ). Low competition and plenty of resources are two crucial factors of adaptive radiation, both of which were met at the time Cetacea evolved.

This was further backed by research by Gianoliin which sister groups of climbing plants that themselves did not have a climbing habit, were found to have less species in 38 out of 48 sister pairs compared. The most important innovations that have led to practically all life on earth today, occurred in a very short period of time relatively short compared to Earths age.

During 40 million years, in the Cambrian explosion, all major phyla's body plans that exist today were formed, plus several other body plans that went extinct Mayr, Some of the major morphological innovations that appeared during the Cambrian explosion included the first coelomate animals animals with a true body cavity and the origin of bilateral symmetry.

Segmented body plans, first external skeletons and appearance of appendages and notochord were also key in further radiations occurring later in history. These innovations made it possible for different ways of making a living and therefore, fill new niches previously unavailable Mayr, Moving much later on, towards the Silurian period, when fish were present, another acquired innovation set about a huge proliferation of species.Why do island chains provide ideal conditions for adaptive radiation to occur?

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Organisms of one species can arrive to an island together and then disperse throughout the chain, each settling into different niches and exploiting different food resources to reduce competition. Cannery row doc essays peinture de la renaissance descriptive essay, apeiron synthesis essay essay om 22 juli profeten expository essay diagram, essay on corpus linguistics research adaptive radiation essay dissertation verlag essay on republic day in bengali komrij essays on the great race identity essay papers do citations count in word count.

Adaptive radiation is the process by which one species evolves into two or more species. This occurs as a result of different populations becoming reproductively isolated from each other, usually by adapting to different environments.

Radiation safety essay Version of radiation in this is the question 1. So does not know about hydrogen-2 and then look at risk is an increase to your college physics. May 11,  · Human skin pigmentation as an adaptation to UV radiation. Nina G. Jablonski 1 and George Chaplin UV Radiation as a Selective Force in the Evolution of Pigmentation.

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Anthropology/Homo Erectus term paper The free Anthropology research paper (Homo Erectus essay) presented on this page should not be viewed as a sample of our on-line writing service. This adaptive radiation was the result of several biological and cultural factors. An example of adaptive radiation is the development of mammals after the extinction of dinosaurs. adaptive variation In evolution adaptive radiation is the idea that you have this relatively rapid or fast expansion, the development of many new species coming from one original common ancestor. Why do island chains provide ideal conditions for adaptive radiation to occur? Organisms of one species can arrive to an island together and then disperse throughout the chain, each settling into different niches and exploiting different food resources to reduce competition.

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