Help me to write my biology essay on evolution.

To write my biology essay on evolution, lets talk about evolution and how it happens. Evolution is the change in any species or population over a period of time. Some traits are taken, some are changed or eliminated. It is by this process of change that occurs in all organism,over the time, results in the evolution.
Evolution results into the change of traits and characters or gene frequency in a population of organisms from one generation to the next. These over span of time might result in extinction of an existing species and origin of a new one. There are many facts and theories given to show the process of evolution and explain why and how evolution takes place. Among all such theories Darwin’s theory of evolution is quite important one. Darwin’s Theory of Evolution says that all life is related and has descended from a common ancestor. For example, humans shared a common ancestor with chimpanzees about eight million years ago, with whales about 60 million years ago, and with kangaroos over 100 million years ago. Either we talk about plants, animals, birds, flowers, all are linked and related. He even believed that complex creatures evolve from more simplistic ancestors naturally over time. Darwin mentioned that natural selection keeps on happening which allows the fittest to survive. Evolutionary change is gradual and a slow process.
Few factors like mutation, migration, and genetic drift are the causes of evolution and variation in organism.