WEIT 2012 Chap7
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 ?
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