There were many theories of evolution prior to Darwin’s Theory of Evolution. Such as, the theory of catastrophism; which was the belief that sudden and violent natural disasters caused the extinction of plants and animals. Then new life forms come in from other places to inhabit the area. Also, the theory of uniformitarianism; which was the belief that the earth was very old, and it was shaped by the same natural forces such as, earthquakes or glacial movements that also occurred at the time (and still occur). These and other theories were debunked by Darwin’s Theory of Evolution. Darwin surmised that animals, plants, and humans evolve over time because “favourable variations would tend to be preserved, and unfavourable ones would be destroyed.” (What is Life? A Guide to Biology, Jay Phelan, page 323) Darwin proposed that natural selection takes place by one of four evolutionary mechanisms; mutation, genetic drift, migration, and natural selection.
Evolution takes place when the proportion of alleles in the population change. This process can occur with one of four evolutionary mechanism’s. The first mechanism is mutation. Mutation is defined as “an alteration of the base-pair sequence of an individual’s DNA, and when this alteration occurs in the
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Which is measured by the organism ability to reproduce successfully. This means that the traits that confer the highest fitness, the ones most suited to the environment, and the success of an organism reproduction compared to another in the population. Another important benefit to natural selection is the ability adapt to the current environment. As humans we have evolved to be more resistance to certain diseases, adaption to certain climates, and foods, as well some physical changes to our bodies; because of these variations our life expectancy is longer than it was a 1000 years ago. Explaining why the worlds is inhabited with over 7 billion