The Theory of Evolution through the use of natural selection is a scientific theory that describes the way that organisms change as a population. This happens over multiple generations where organisms change to fit their environment better. This theory was most famously proposed by Charles Darwin in 1835 when he went to the Galapagos Islands. He had noticed that finches from different islands were not varieties of one species, but different ones entirely. He then developed a hypothesis about how this may have happened. He thought that the animals randomly change over time and the ones that have good changes are able to survive and reproduce, while the ones with changes that do nothing or hurt them are less likely to survive.

“One general law, leading to the advancement of all organic beings, namely, multiply, vary, let the strongest live and the weakest die.”
~ Charles Darwin's The Origin of Species