Natural selection is a key idea of the theory of evolution by Charles Darwin. Natural selection refers to survival and/or reproductive advantages a species has, over the rest of the population, due to certain adaptations or features. Species do adapt over time and evolve in order to survive and reproduce. For example, say all species of deer, except for musk deer, are eaten by predators. In such a scenario musk deer will survive and reproduce. Any other deer species will only survive if they adapt to such an environment, by say producing an odor or changing habitats, etc. Musk deer will also have to adapt at producing stronger scent or develop any other adaptation, since after all the other deer are dead, they will be the only food choice for predators. Thus, natural selection results in evolutionary changes.
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