the origin of species by natural selection

Those that are lacking in such fitness, on the other hand, either do not reach an age when they can reproduce or produce fewer offspring than their counterparts. Those that are better physically equipped to survive, grow to maturity, and reproduce.

In the theory of natural selection, organisms produce more offspring than are able to survive in their environment. Darwin and a scientific contemporary of his, Alfred Russel Wallace, proposed that evolution occurs because of a phenomenon called natural selection. But evolution did not reach the status of being a scientific theory until Darwin’s grandson, the more famous Charles Darwin, published his famous book On the Origin of Species. When it comes to the evolution of life, various philosophers and scientists, including an eighteenth-century English doctor named Erasmus Darwin, proposed different aspects of what later would become evolutionary theory. Scientists talk about evolution as a theory, for instance, just as they talk about Einstein’s explanation of gravity as a theory.Ī theory is an idea about how something in nature works that has gone through rigorous testing through observations and experiments designed to prove the idea right or wrong. In science, the word “theory” indicates a very high level of certainty. His idea, however, was not a theory in the scientific meaning of the word, because it could not be subjected to testing that might support it or prove it wrong. From this reasoning, he proposed that all life began in the sea.Īnaximander was correct humans can indeed trace our ancestry back to fish. He concluded that those ancestors must be fish, since fish hatch from eggs and immediately begin living with no help from their parents. Noting that human babies are born helpless, Anaximander speculated that humans must have descended from some other type of creature whose young could survive without any help. Ideas aimed at explaining how organisms change, or evolve, over time date back to Anaximander of Miletus, a Greek philosopher who lived in the 500s B.C.E.

The origin of species by natural selection