Final answer:
Charles Darwin provided evidence for evolution by natural selection through his observations of the Galápagos Islands' species, the fossil record, and the principles of inheritance, overproduction, and variation. He argued that beneficial traits, passed on to offspring, contribute to species changing over generations, not a unique creation for the environment.
Step-by-step explanation:
Charles Darwin's Evidence for Evolution by Natural Selection
Charles Darwin presented significant evidence to support the view that species undergo evolution by natural selection rather than being created individually for their environments. In his seminal work, On the Origin of Species, Darwin included observations from his voyage aboard the HMS Beagle, particularly from his time in the Galápagos Islands where he observed species uniquely adapted to specific settings. He used the fossil record to show gradual changes over time in living organisms.
Darwin's theory was based on three main principles: Firstly, that traits are inherited from parents to offspring. Secondly, that more offspring are produced than can possibly survive, thus creating a struggle for the limited resources available. Lastly, due to variation among offspring, those with beneficial inherited traits that fit their environment are more likely to survive and reproduce, passing those traits on to future generations. This process he called descent with modification, and it leads to populations becoming increasingly adapted to their local environments.
These principles, bolstered by examples such as the varying beak shapes of finches on different islands, which were suited to specific types of food sources, underpin Darwin's theory of evolution by natural selection. His theory posited that the successful adaptations are a result of random variation and not a predetermined plan, advancing the idea that evolution is driven by survival in a competitive natural world.