According to de-Vries, what is saltation?

Hugo de Vries was a Dutch botanist and geneticist who is known for his work on the theory of evolution and heredity. He is best known for his theory of saltation, which was a proposed mechanism for evolutionary change.

Saltation, in the context of de Vries's theory, suggests that evolution can occur in sudden and dramatic leaps or jumps, rather than through gradual, incremental changes as proposed by Charles Darwin's theory of natural selection. De Vries believed that new species could arise through the sudden appearance of individuals with distinct and advantageous traits, rather than through the gradual accumulation of small variations.

De Vries's ideas on saltation were developed in the early 20th century and were part of the broader debate on the mechanisms of evolution at the time. However, it's important to note that saltationism as a dominant theory of evolution has been largely rejected by the scientific community. Instead, modern evolutionary biology largely supports the idea that evolutionary change occurs through a combination of gradual accumulation of genetic variations (as proposed by Darwin) and other mechanisms such as genetic drift, gene flow, and natural selection.