Evolution is the changes seen in the growth, development, features of a certain group of species during the cause of time. Evolution causes changes in the gene frequency of species from one generation to the next generation.
There are 5 important mechanisms of evolution and they are: Gene flow, mutation, genetic drift, natural selection and non random mating.
Gene flow as a mechanism of evolution is the exchange or transfer of genes between a group of species as they move from one place to another. Gene flow can either increase the rate of evolution or decrease it.
a potential source of confusion in constructing a phylogeny is similarity between organisms that is due to convergent evolution - called analogy - rather than to shared ancestry. thus for mammals, the backbone is a shared ancestral character, a character that originated in an ancestor of the taxon