Week 3 Day 5 - The obvious fact is that there had to be...

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I believe the chapter six animation to be an example of secondary succession. The area had an ecosystem in place prior to the beavers creating the dam, that caused the domino effect to begin. Plus the ecosystem was not destroyed, it was just altered from what it was originally. Over time evolution helped transform the area back to near what it was before the beaver dam was built. Even though through years of evolution, the area appears to have looked the same throughout history, there will always be evidence of the effect the beaver dam had on this ecosystem. Although most salamanders have four legs, the aquatic salamander shown below resembles an eel. It lacks hind limbs and has very tiny forelimbs. Propose a hypothesis to explain how limbless salamanders evolved according to Darwin's theory of natural selection.
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Unformatted text preview: The obvious fact is that there had to be some kind of reason required for this species, of aquatic salamander, to evolve itself to have no back limbs and only tiny forelimbs. Through Darwins theory of natural selection, I believe that the reason for this would fall under rule three; limits on population growth, or a struggle for existence. While four limbs are a blessing on land, they would cause a creature in water to be a much slower swimmer. This could make them become much easier prey for predators. Not needing the back limbs in water, the aquatic salamander over years eliminated them all together. The fact that the forelimbs are tiny are an example, in my opinion, that they are in the process of removing them as well....
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