进化生物学:岛屿上的相似植物物种化?

Overview

Speciation describes the formation of one or more new species from one or sometimes multiple original species. The resulting species are discrete from the parent species, and barriers to reproduction will typically exist. There are two primary mechanisms, speciation with and without geographic isolation—allopatric and sympatric speciation, respectively.

Overview

Speciation is the evolutionary process resulting in the formation of new, distinct species—groups of reproductively isolated populations.

Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.

Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of novel varieties and entire new species. These changes are responsible for the diverse forms of life inhabiting the planet. The evidence for evolution suggests that all living organisms descended from common ancestors.