The Theory of Evolution
More than 150 years after Charles Darwin published his theory, evolution remains controversial.
A gradual process in which something changes into a different and usually more complex or better form over a long period of time.
The different beaks on these birds have adapted to the habitat over a long period of time. The food source such as seeds were harder for the finches to eat because of there beaks, so as time went by there beaks were adapting to the food.
In the biological sciences, evolution is a scientific theory that explains the emergence of new varieties of living things in the past and in the present; it is not a "theory of origins" about how life began.
