One of the most overlooked and yet powerful aspects of Darwin's theory of evolution is that it embraces a wide and expansive period of time. When people understand Darwin as advocating the changing of organisms, they seem to think it is something immediate. For example, man came from a monkey. This is an oversimplification. Darwin's point is that organisms lived in their environment and adapted to the realities within it. This adaptation is what allowed them to thrive and survive and not perish. Over time, these changes became a part of the organisms' history and a part of their identity. It is this reality of change and adaptation which transpires over a long period of time that helps to define change and mutability in all organisms.
Overview and main points:
Evolution: To transform, change, or improve a condition from its original condition.
Darwin: All living things came from non-life, and from their onset, they all share things in common that make them related. We are all living beings sharing living characteristics. Individually, different species have different origins. (We also know now that he was right in that all organisms are related: Carbon is what makes organisms exist)
Variations within each species (survival of the fittest, or natural selection) are possible when the organism is fit and strong enough to change as its environment changes.
Just like in the beginning, species change entirely as the variations and mutations strengthen or weaken them. Only the strong, and those willing to adapt, will make it.
The major point of Darwin's theory is that species are created by the process of natural selection. Organisms evolve through a process of "survival of the fittest" where the organisms best adapted to a certain environmental niche survive and those that are not so well adapted die. Eventually, change can occur to the extent that a new species exists that is different from its ancestor species.
This is important for biology because it gives us what is now the most commonly accepted theory of how speciation occurs. It has been important societally because it has led to ideas such as Social Darwinism and because it has led to a great deal of controversy (especially in the US) between believers in Biblical creation and those who ascribe to Darwin's theory.
Darwin’s theory is known as evolution by natural selection. This theory holds that in the struggle for life changes and variations within a species that are profitable to preservation of life will be inherited by offspring. In the same manner, those unfavorable or injurious characteristics will not be inherited by offspring. Darwin added to theories of emotion, motivation, and memory.
Darwin also had a view on motivation; his views all related to the survival of the species. For example, he believes that humans evolved preference for sweet tastes during a time of shortage of food; because sweets are a rich source of energy people were motivated to prefer them for which enhanced the chance of survival (Deckers, 2005).
Darwin believed an individual’s emotions were based on hereditary. Darwin’s theory of the evolution of emotional expression concludes that facial expressions of emotion are hard-wired by evolution. He also held that some emotional responses in humans such as the bristling of hair when experiencing extreme fear could only be understood and explained in that man had existed at in a lower animal-like state (Goodwin, 2005). Darwin conducted studies proving that many emotional expressions were the same cross-culturally and even cross-species (Kowalski & Westen, 2005).
Darwin held that humans, and other species, have an evolutionary history. This history is stored in human genes rather than a specific place in the brain. So, in a sense this evolutionary history constitutes a collective memory for the species.