Heredity, Natural Selection, and Evolution

Species and Population

What did Hugo de Vries discover about species populations?

Dutch botanist Hugo de Vries (1848–1935) discovered a way in which a population could become a separate species while still sharing the same environment with other members of the species. The process, known as sympatric speciation, occurs almost exclusively in plants rather than in animals and involves a series of rare genetic accidents that can occur during the formation of gametes (eggs and sperm). As a result, gametes are formed as polyploids—that is, they have extra copies of each chromosome and thus are unable to match their chromosomes to others of the same species. Since these poly ploids are forced to mate only with other polyploids in the population, they are reproductively isolated and considered a new species.


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