Evolution, theory in biology postulating that the various types of living things on Earth have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations.
Evolution is the change in characteristics of populations of organisms over time. Changes can be small, for example, a small change in body size or a change in the color of a species’ fur. Over many generations evolutionary change can result in the evolution of new structures such as wings, or new functions such as photosynthesis. Evolutionary change can profoundly affect the Earth system ...
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.54 ± 0.05 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1][2][3] The similarities among all known present-day species indicate that they have diverged ...Evolution can be seen as a two-step process. First, hereditary variation takes place; second, selection is made of those genetic variants that will be passed on most effectively to the following generations.