Neo-Darwinism

August Weismann and Alfred Russel Wallace rejected the Lamarckian idea of inheritance of acquired characteristics that Darwin had accepted and later expanded upon in his writings on heredity.

[1]: 108 [2][3] The basis for the complete rejection of Lamarckism was Weismann's germ plasm theory.

Since he could see no obvious means of communication between the two, he asserted that the inheritance of acquired characteristics was therefore impossible; a conclusion now known as the Weismann barrier.

Romanes used the term to describe the combination of natural selection and Weismann's germ plasm theory that evolution occurs solely through natural selection, and not by the inheritance of acquired characteristics resulting from use or disuse, thus using the word to mean "Darwinism without Lamarckism.

For example, Ernst Mayr wrote in 1984 that: Publications such as Encyclopædia Britannica use neo-Darwinism to refer to current-consensus evolutionary theory, not the version prevalent during the early 20th century.

Friedrich Leopold August Weismann , considered the "founder of Neo-Darwinism" for expanding Darwin's theory along genetic lines
George John Romanes originally used Neo-Darwinism in 1895 to refer to an early modification of Darwin's theory. Photograph by Elliott & Fry (1896)
Several major ideas about evolution came together in the population genetics of the early 20th century to form the so-called modern synthesis , including genetic variation , natural selection , and particulate ( Mendelian ) inheritance. This was at the time called neo-Darwinism.