Biological Evolution

Ø According to Darwin, evolution took place by natural selection.

Ø The number of life forms depends upon their ability to multiply and their life span.

Ø Another aspect of natural selection is the survival of the fittest, where nature selects the individuals, which are most fit, to adapt to their environment.

Ø Branching descent and natural selection are the two important concepts of Darwin’s theory of evolution.

Ø The French naturalist Lamarck observed that evolution occurs due to the use or disuse of particular organs or body parts. For example, giraffe have developed long necks as a result of attempts to eat leaves high up on trees.

Ø Darwin also observed that variations are inheritable and the species fit to survive the most, leaves more offsprings. Hence, the population’s characteristics change, giving rise to the evolution of new life forms.