Charles Darwin's Controversial Theory Of Evolution

In 1859, English Biologist Charles Darwin suggested a process in which species change over time which is known as natural selection. Darwin did not discover natural selection using genetics as he had no knowledge of genetics since it had not been discovered. Since then genetics has provided the solid evidence to support natural selection as the process by which evolution occurs. He began his journey in 1831 when he went to work on the HMS Beagle where he spent five years drawing maps of lands they visited and keeping a journal of their findings with his crew members. Darwin observed that many species that were related, faintly differed depending on where they were found. Darwin’s observation was influenced by the writings of Thomas Malthus, who proposed a constant battle for survival among species which led to Darwin’s Controversial theory The Origin of species in 1859. A century has passed since Darwin has presented his Theory of Evolution through natural selection where he argued that species

Over a long period of time organisms on an island change so they can no longer interbreed with organisms on different islands, the inability to interbreed in known as reproductive isolation. Reproductive isolation is due to Geographical isolation. A population can be geographically split in many ways which include Rivers form, Sea levels rise and fall, walls getting build, continents drift, climate isolation etc. If the environment conditions change for these populations they would then adapt to that environment, hence as long as they is no Gene flow between the two populations, they would genetically become different that they could no longer interbreed. An example of this includes a species of birds that once lived together, however now live on separate nearby