One of the first scientists to propose evolution formally was Charles Darwin’s grandfather, Erasmus Darwin. Erasmus wrote, these theories in Zoonomia, or, the Laws of Organic Life. He was the first to discuss about how life evolved from “a single common ancestor.” The idea was that a species evolved over a period of time through a long series of accidental changes in the genes or traits of the species. This idea was called natural selection. For as members of a species would die off, the strongest ones with the best genes would survive longer, giving them more of a chance to reproduce offspring with those traits. This continues from one generation to the next, forever improving, forever changing. Jean-Baptiste Lamarck though, had an entirely different idea.
In his theory, evolution happened because of a change in environment as opposed to a change in traits. Lamarck said that the reason anything evolved was because of its “need” to change based on the environment that it is in. Take wolves for example. If said wolves are put into a new environment with faster prey or a new predator, the population will grow stronger and become superior to the new challenges. According to Lamarck, these superior skills will be passed down to the next generation.
It is this type of change that is classified as, microevolution or “evolution on a small scale—within a single population.” In a certain population a microevolution is a change in gene frequency. These can happen in different ways or “mechanisms”, Mutation, Migration, genetic drift, and natural selection. Mutation is genes in just randomly mutating from one type to another, such as, blue genes mutating to green. Migration is a transfer of genes that are integrated from another population through either emigration or immigration. A genetic drift is when, by luck, more of one gene is reproduced than the other and each generation it changes. For natural selection see the definition in the paragraph on Darwin.
People may ask, wheres the evidence of evolution? The short answer is that you look at it everyday. Humans in general are evidence of evolution. Archeaologists all over the world have found skeletons that are almost identical to ours today. the most obvious observation is the size of human's lower jaw today compared with an anncestor from thousands of years ago. Ours it much shorter, which is why we must have the wisdom teeth removed. This would be considered MACROevolution. The facial changes happened over a very long period of time and took many generations to become distinct. MICROevolution would have seen this change in one or two generation.
Scientifically, no. Humans did not come from monkeys. But if we did, it would have been from apes. In my opinion, Darwin has the most accurate and correct theory. Evolution happens on its own through natural selection of what genes mutate and are passed to the next generation. It is not possible for a physical change due to a need for it to be passed down to the next generation, especially if it is only about the enviroment that the population is in.
bibliography:
"A History of Evolutionary Thought." UCMP, 1994. Web. 17 May 2011. http://www.ucmp.berkeley.edu/history/evothought.html
"Microevolution." UCMP. Web. 17 May 2011. http://www.ucmp.berkeley.edu/history/evothought.html.