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Example of Evolution
Here is an example of evolution; the evolution of the horse through time. Remember that this process of change took place over millions of years, but we have a recorded snapshot of it in the fossil record. As natural variations within the species let some individuals reproduce with better success than others, the gene pool shifted with time. It may have played out like this:
The earliest horses had short legs and spread out toes to accommodate walking in moist soft ground of the early forests on Earth. Later, grasses spread over much of the Earth and new predators developed that could chase and kill horses. The horses with natural variations that helped them run faster were the ones who survived (the others were eaten). The better runners had longer legs and some of the toes slightly lifted, which gave them a spring action when they ran. This trait was passed on and gradually became more prevalent in the species. Over time, longer legs and slightly lifted toes became the new normal. Longer legs were selected for, and shorter legs were selected against until individuals with short legs were no longer left to reproduce and pass on their traits.
