Question

What is ‘Saltation’?

Answer 1

Hint: Saltation is a type of sudden and large-scale mutational change from one generation to the next and has the potential of causing single-step speciation. Additionally, it was historically offered as a substitute for the theory of Darwinism.

Complete answer:
Hugo de Vries was a known Dutch botanist and geneticist. He also presented the experimental study of organic evolution to the world. His work mainly in the field of heredity and its relation to the origin of species gave rise to the mutation theory. He also brought the prior work of Gregor Mendel to the attention of the world and finally introduced the word saltation. According to him, evolution is caused by abrupt large differences in the population i.e mutation, and not the minor variations as per Darwin.

Additional information:
Hugo de Vries in his research discovered new forms or varieties that appeared randomly among the host of ordinary specimens when he cultivated evening primrose(Oenothera lamarckiana). He named this phenomenon as mutation, which he showed to arise suddenly, as distinct from Darwin’s variation of species through natural selection. He believed these variations to be an example of an evolution that could be considered experimentally and conceived of evolution as a series of sudden changes. These sudden changes were radical enough to bring new species into existence in a single leap.
-De Vries termed these suddenly-appearing variations as mutations, and in his The Mutation Theory, he suggested that evolution might occur more habitually by these large-scale jumps than Darwin’s natural selection acting on slight individual variations.
-Mutations are random and directionless in contrast to Darwin’s theory which stated these variations in population as small and directional.

Notes:
De Vries was also the first person to suggest the occurrence of recombination between homologous chromosomes, now known as chromosomal crossovers, within a year after chromosomes were implicated in Mendelian inheritance by Walter Sutton.