... that an introduced species gains in its lifetime when it faces a different environment- but this doesn't provide a sufficient explanation for evolution, because adaptations cannot be inherited. This, among many other theories, is incorrect. The theory that most scientists support, however, is that of natural selection. Basically, the theory states that naturally, every organism will posses genetic variation. In some situations, this variation in their genes may give them an advantage over the other animals; for example they may have a slightly longer neck to eat leaves with, or larger leaves so soak up more sun. In effect, these animals will most probably survive longer. They will then breed with another organism, and their characteristics, caused by mutations within their gene pool, will be inherited by their offspring. The offspring will pass on their variations to their offspring, and this cycle continues. Because of this, there is much ...

See this essay or coursework document in full right now