Natural+Selection


 * In 1858, another British bioligist, Alfred Russel Wallace, each proposed an explanation for how evolution could occur in nature.
 * Darwin made a book and in it he proposed that evolution occurs by means of natural selection.
 * Natural Selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce than other members of the same species.
 * Overproduction took place when Darwin knew that most species produce far more offspring than can possibly survive. It means that more offspring are produces that their isnt much resources for them to survive.
 * Competition took place since food and resources were limited, the members of a species had to compete with each other for it, in order to survive. The competition is usually indirect.
 * Any diffrence between individuals of the same species is called a variation. Members of a species differ from one another in many of their traits.
 * Selection took place when Darwin proposed that over a long period of time, natural selection can lead to change. Helpful variations gradually accumulate in a species, while unfavorable ones disappear.
 * Darwin observed that some variations make individuals better adapted to their environment.
 * A change in environmental conditions can affect an organisms ability to survive, and therefore leading to selection.
 * Without variations, all the members of a species would have the same traits.
 * Later scientists learned that variations can result from the shufflings of alleles during meiosis.
 * In a 1977 study of the finches on Daphne Major, one of the Galapagos Islands, scientists observed that beak size could change very quickly by natural selection.
 * A new species might form when a group of individuals remains seperated from the rest of its species long enough to accumulate different traits.
 * Darwin supported that the idea of geographic isolation is one of the main ways that new species could form.
 * Evidence indicated hundreds of millions of years ago all of Earths landmasses were connected as one landmass.
 * Organisms could migrate from one part of the supercontinent to another.
 * As the continents seperated, their environments changed and species became isolated from one another, and natural selection happened.