Although Charles Darwin was the first to conceive the idea of natural selection and evolution, he was not the first to have thoughts and questions about the multitude of life. The earliest of philosophers had their thoughts on biological life surrounded by creationism and the theory of a divine plan. Darwin's Theory of evolution and natural selection was both radical and daring; he would undoubtedly need empirical proof for support.
Charles Darwin was the first to introduce the idea that all organisms may stem from common ancestry. He called this process natural selection. He did not seek to answer the question of creation, but simply explain a possible system for this diversity. Natural selection and evolution is the process in which organisms develop characteristics and these characteristics become more common if it is favorable for survival in a given environment. Over time, the desirable characteristic becomes pronounced within a given species because it provides a substantial advantage to the organisms that possess it. After thousands of generations the characteristic is so pronounced that it has its own species classification. Darwin theorized that organisms all stem from a few common ancestors. Natural selection based on each organism's given environment is responsible for the diversity of life that is visible today.
A new species is created when a trait becomes beneficial enough to species reproduction that it is producing more offspring than its relative. A new species can also be created due to development of different traits based on isolation and separate environments. The traits develop to cater to each environment which turns one species into two or more.
In order to prove and expand his theory of natural selection, it was important for Darwin to work in the field and explore the possibilities of life, as daunting a task at that must have seemed. Darwin's most famous exploration is easily the Galapagos Islands and his observation of the organisms he found there. Located right on the equator, this set of islands had never been explored and were relatively new islands which had only been formed about 5 million years ago. The isolation of these islands and their relatively recent formation is significant, because it creates the opportunity to observe a standalone habitat. Additionally, because each of these islands is isolated from one another, a species that originally landed on two different islands could potentially be observed as developing specific characteristics over time proving natural selection to be correct. Darwin Brought back many new species on his voyages to the Galapagos, but his most famous find was observation of multiple finch species. A theory is that a group of finches was knocked off their usual course and sent to these islands. The finches each developed very observable and unique traits from the same ancestor. The traits of each species of finch were perfectly tuned for the type of resources available on these islands respectively. Darwin discovered a vast diversity in these groups of finches most notable in their varying beak sizes. This was very significant empirical support to Darwin's theory of Natural selection.
The study of Darwin's finches has lead to many other significant theories regarding species evolution and species competition. G.F. Gause proposed that two species that have identical needs cannot coexist. Eventually, one species will have an advantage over the other and be the victor for the resources. This idea was called “The Competitive Exclusion Principle”, which states that the competing species will result in the extinction of one of them or one or both of the species will evolve until they are less competitive for resources.
Darwin's Finches were used as an example of this principle. Two species of finches can live on the same island due to their difference in bill size. One has a large bill and the other a small bill. This creates a difference in preference for the types of seeds that are ideal. This idea of evolution creating less competition is called Character Displacement.
Darwin’s Natural Selection created a whirlwind of research and is still relevant to modern empirical studies and theories of evolution. The idea of Directional Selection was based on the Darwin's theories. Directional Selection is when Natural selection favors one extreme over another within a given population.
While directional selection is very one sided, the concept of “Stabilizing Selection” favors the normal or average of a given trait and in contrast “Disruptive selection” favors the organisms outside of the norm on either side.
Darwin's trip to the Galapagos Islands not only gave him the proof needed to support his evolutionary theory, but it also had a profound influence of the research direction of evolution after it was deemed credible.