Charles Robert Darwin, was an English naturalist. He established that all species of life have descended over time from common ancestors, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection, in which the struggle for existence has a similar effect to the artificial selection involved in selective breeding.

Darwin's Theory of Evolution is the widely held notion that all life is related and has been descended from a common ancestor. The birds, animals, humans and other forms of life are all related. He also stated that the development of life from non–life and stresses a purely naturalistic “descent with modification”. That is, complex creatures evolve from more simplistic ancestors naturally over time.

Life's dual nature of Unity and Diversity: The process of evolution illuminates both the similarities and differences among Earth's life. The Origin of Species articulated two main points. First, Darwin presented evidence to support his view that contemporary species arose from a succession of ancestors. Darwin called this evolutionary history of species ‘descent with modification’.

It was an insightful phrase, as it captured the duality of life's unity and diversity – unity in the kinship among species that descended from common ancestors; diversity in the modifications that evolved as species branched from their common ancestors. Darwin's second main point was to propose a mechanism for descent with modification. He called this evolutionary mechanism – natural selection.

Thus, all forms of life have common unifying features yet are amazingly diverse. Both of these facts are a result of our DNA . Similarities exists when common ancestors are recent, diversity occurs when genetics and environment interact and natural selection occurs. Adaptations are features that make an organism particularly well suited to its environment. Unity in the diversity – DNA is the common language of life.

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