« WEIT 2012 Chap7 » : différence entre les versions
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=How do species appear ?= | =How do species appear ?= | ||
Most of the time speciation occurs because of a geographic barrier, but it can also occur without. | |||
==What are geographic barriers and how do they affect speciation ? == | |||
Geographic barriers are natural elements such as moutains or seas which split one or several species in different places. <br> | |||
For example, a population of a certain species of plant could be split in two if an island split in two because of erosion.<br> | |||
They affect speciation because the species continues to evolve and to develop specific characterisics, if they are split they will certainly develop different characteristics and since they can't interbreed they won't "share" these new characteristics and will eventually develop in different species. | |||
==What are the other ways that speciation occurs ?== | |||
--[[Utilisateur:RaphaelB|RaphaelB]] 9 mars 2012 à 16:36 (CET) | |||
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*retour à [[Evolution_3BIbDF10-11_2011/12]]<br> | *retour à [[Evolution_3BIbDF10-11_2011/12]]<br> | ||
*retour à [[Accueil]] | *retour à [[Accueil]] | ||
Version du 9 mars 2012 à 17:36
THE ORIGIN OF SPECIES
A species ? What's that ?!
First of all, we will define a species as a group of population whose members have the potential to reproduce with one another in nature ; and thus produce fertile offspring. Actually a reproduce compatibility is useful and more important than a physical similarity ! For example, a woman coming from Japan can marry a French man and they can have children together even if visually the two parents don't look the same.
Different ways of defining species
Saying that species are individuals that look alike would be a very simplified version of the definition of the species meaning. In fact there are several ways of defining a species; and being or not a species depends of many parameters. As mentioned previously, defining species by their appearance is possible...But there exists some animals such as the eastern meadowlark and the western one (some kind of birds living in North America) are extremely similar in appearance, however they aren't from the species at all, moreover they don't interbreed (which means reproduce with one another)!
How do species appear ?
Most of the time speciation occurs because of a geographic barrier, but it can also occur without.
What are geographic barriers and how do they affect speciation ?
Geographic barriers are natural elements such as moutains or seas which split one or several species in different places.
For example, a population of a certain species of plant could be split in two if an island split in two because of erosion.
They affect speciation because the species continues to evolve and to develop specific characterisics, if they are split they will certainly develop different characteristics and since they can't interbreed they won't "share" these new characteristics and will eventually develop in different species.
What are the other ways that speciation occurs ?
--RaphaelB 9 mars 2012 à 16:36 (CET)
- retour à Evolution_3BIbDF10-11_2011/12
- retour à Accueil