On the 16th of February 1848, Hugo de Vries was born. De Vries was a biologist and early geneticist.
He studied Biology at Leiden University and did his PhD on the effect of temperature on roots. He became professor in Botany at the University of Amsterdam.
He played a vital role in the rediscovery of Mendel’s Law’s of heridity. Together with Carl Correns and Erich von Tschermark, he is a founder of the modern evolution theory.
De Vries had done a lot of experiments crossbreeding various plants, and concluded that the qualities a plant inherited (colour of the leaves, etc) was made up of several units. Every inheritable quality corresponds with something that carries that material. Nowadays, we use the word ‘genes’ but De Vries used the word 'pangenes’, based on Darwin’s pangenesis-hypothesis. Darwin assumed that traits a parent acquired during their lifetime could be inherited by a child. The word 'genes’ is derived from 'pangenes’.
From his experiments he also derived his mutation theory, where he wrote that new species could evolve with bigger jumps than Darwin assumed. Most of his research he did on the large-flowered evening primrose. These plants have a special way of pairing and recombining their chromosomes when being bred, which means an offspring can be very different from its parents. De Vries assumed this recombination of maternal and paternal chromosomes were actually mutations.
So while his theories on pangenes and heridity no longer hold up, his role in evolution is invaluable.