Evolution is any change to later generations in the heritable characteristics of populations . Evolutionary processes give life diversity at every level of biological organization , such as species , individual organisms and molecules such as DNA and proteins .
Life on Earth began and evolved from a universal common ancestor about 3.7 billion years ago . The emergence of new creatures and divergence of life can be witnessed by a joint group of biochemical and morphological features , or common sequences of DNA . These features and homologous sequences are similar among the species that have an ancestor on new and can be used to reconstruct the evolutionary history based on records of fossil and current species . Today's structure is formed as biodiversity from extinction , as the emergence of new species .
Charles Darwin was the first to formulate a scientific argument for the theory of evolution by natural selection mechanism . Evolution by natural selection is a process that is evidenced by three facts about populations : 1 ) more offspring are produced than survive , 2 ) traits are different for each individual , leading to different ratios of survival and reproduction , and 3 ) changes in features hereditary . [ 3 ] Thus, when members of a population die , they are replaced by the offspring of parents who adapted better to survive and reproduce in the environment in which natural selection occurred . This process creates and preserves the features that are most suitable to perform biological functions . Natural selection is the only known cause of adaptation , but not the sole cause of evolution . Other , non - adapter causes evolution are mutation and genetic deviation .
In the early 20th century , genetics was integrated with the Darwinian theory of evolution by natural selection through the discipline of population genetics . The importance of natural selection as the cause of evolution was accepted in other branches of biology . In addition, the old notions of evolution , as orthogenesis and "progress " became worthless . Scientists continue to study various aspects of evolution are given and tested hypotheses , scientific theories built by observers as data and perform experiments in the field and in the laboratory . Biologists recognize that seed with modification is one of the most reliable facts in science . ] Discoveries in evolutionary biology have conducted an impact not only in the traditional branches of biology , but also in other academic disciplines ( p.sh , anthropology and psychology ) and in Friends .