AP BIOLOGY

Detailed explanation-1: -Life began on Earth at least 3.5 to 4 billion years ago, and it has been evolving ever since. Darwin stated the theory of evolution by natural selection, presenting a great deal of evidence to support his theory.

Detailed explanation-2: -Darwin proposed that species can change over time, that new species come from pre-existing species, and that all species share a common ancestor. In this model, each species has its own unique set of heritable (genetic) differences from the common ancestor, which have accumulated gradually over very long time periods.

Detailed explanation-3: -Darwin believed all the life on Earth developed gradually over millions of years from a few common ancestors. The Darwin mission will survey 1000 of the closest stars, looking for small, rocky planets which are the most likely places for life to develop-at least as we know it.