Jean Baptiste Lamarck The French Naturalist Jean Baptiste Lamarck pronounced the first comprehensive theory of evolution in the beginnings of the 19th century. His theory, the theory of acquired characteristics, had three parts and is as follows: 1) Theory of need- the production of a new organ or part of a plant or animal results from a need 2) Theory of use and disuse- organs remain active as long as they are being used but disappear gradually …showed first 75 words of 1330 total…

…showed last 75 words of 1330 total…method. His results also provided the scientific world with many new theories of inheritance, which expanded upon the theories of Mendel. Morgan’s work, without question, helped biologists succeeding him to develop new ideas or expand upon others. Alfred Sturtevant and Calvin Bridges, both students of Morgan, worked with his ideas. Sturtevant provided proof of genetic linkage, while Bridges advanced the theory of chromosomal non-disjunction, and did a lot of work on chromosomal banding patterns.