Evolution (also called biological or organic evolution) is the change over time in or more inherited traits present in populations of organisms.[1] Inherited traits are particular distinguishing characteristics, including anatomical, biochemical or behavioural characteristics, that are passed on from generation to the next. Phenotypic expressions of these traits can be influenced by geneenvironment interactions. Evolution may occur when there is variation of inherited traits within a population. The major sources of such variation are mutation, genetic recombination and gene flow.[2][3][4][5] Evolution has led to the diversification of all living organisms, which are described by Charles Darwin as "endless forms most stunning and most wonderful".
In speciation, a single ancestral species splits in to or more different species. Speciation is visible in anatomical, genetic and other similarities between groups of organisms, geographical distribution of related species, the fossil record and the recorded genetic changes in living organisms over lots of generations. Speciation stretches back over four.5 billion years in the coursework of which life has existed on earth.[9][10][11][12] It is thought to occur in multiple ways such as slowly, steadily and gradually over time or quickly from long static state to another.
Two processes are usually distinguished as common causes of evolution. is natural choice, a process in which there is differential survival and/or reproduction of organisms that differ in or more inherited traits.[1] Another cause is genetic drift, a process in which there's random changes to the proportions of or more inherited traits within a population.[7][8]
In speciation, a single ancestral species splits in to or more different species. Speciation is visible in anatomical, genetic and other similarities between groups of organisms, geographical distribution of related species, the fossil record and the recorded genetic changes in living organisms over lots of generations. Speciation stretches back over four.5 billion years in the coursework of which life has existed on earth.[9][10][11][12] It is thought to occur in multiple ways such as slowly, steadily and gradually over time or quickly from long static state to another.
Two processes are usually distinguished as common causes of evolution. is natural choice, a process in which there is differential survival and/or reproduction of organisms that differ in or more inherited traits.[1] Another cause is genetic drift, a process in which there's random changes to the proportions of or more inherited traits within a population.[7][8]