How did the work of Gregor Mendel contribute to our current understanding of evolution and speciation?

He provided a basic understanding of mechanisms involved in heredity.

Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. He deduced that genes come in pairs and are inherited as distinct units, one from each parent. Mendel tracked the segregation of parental genes and their appearance in the offspring as dominant or recessive traits.