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Homologous vs Analogous Structures

Submitted by bthoole on Mon, 10/01/2018 - 17:30

Evolution is driven by natural selective processes but has no end goal or “perfect” structure or creation. The evolutionary development of species is driven by the opening of a niche and the fulfillment of that area to the best degree. Over time, this can result in structures that are similar in design or function between species. However, as taxonomists or biologists, it is important to understand the underlaying commonalities of the common ancestor of the similar species. The structure in question could either by the result of a shared common ancestor and the further development of the trait to fill a niche. These structures are known as homologous structures. An example of such structures would be the bones in the arm of a human and wing of a bat. On the surface they are different structures, but the bone shape and structure appear in similar shape and structure due to sharing a common ancestor. However, similar traits can arise because of convergent evolution, a process where evolutionary pressures cause for the need of the structure. The resulting structures from this kind of evolution are known as analogous structures. An example of this would be the wing of a bird and the wings of an insect. While they both developed wings, the structures themselves are derived from different evolutionary pressures. There is not a shared common ancestry between the two enclaves that would have given rise to wings in both.

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