Elaborate Evolution by Natural Selection ?

The conelaboratecept of natural selection lies at the heart of Darwin's Theory of Evolution. Darwin understood that plants and animals being raised for food or show in his day were selectively bred, or artificially selected for certain valued traits. Darwin came to understand that environmental factors such as predators, food supply, physical habitat, and climate functioned in much the same way to select and favor specific characteristics or traits. Those organisms within a population that could effectively reproduce in a given environment would be able to reproduce effectively.

Evolution might have occurred as described in the example below. Genetic recombination leads to variation among the individuals of any population, in this case, in the neck length in a population of giraffes. In a changing environment, food resources is consumed in order of accessibility. As food becomes scarce, most giraffes suffer from poor health, or starvation. However, giraffes with longer than normal necks are able to reach more food, and have an advantage in surviving to produce offspring, who are genetically likely to be longer necked as well. Over time, by natural selection, the population evolves into one of longer necked giraffes.