Dobzhansky, who emigrated to the United States in 1928, worked in Thomas Hunt Morgan's "Fly Room," where were being studied closely for the first time. He also paid careful attention to the work of population geneticists such as Sewall Wright, who were showing how the size of a population affects the rate at which a mutation can spread. Dobzhansky was interested in discovering the genetics that determined the differences between populations of a species.
At the time, most biologists assumed that all of the members of any given species had practically identical genes. But these were assumptions bred in the lab. Dobzhansky began analyzing the genes of wild fruit flies, traveling from Canada to Mexico to catch members of the species . He found that different populations of did not have identical sets of genes. Each population of fruit flies he studied bore distinctive markers in its chromosomes that distinguished it from other populations. If there was no standard set of genes that distinguished a species, what kept species distinct from each other? The answer, Dobzhansky correctly realized, was sex. A species is simply a group of animals or plants that reproduces primarily among themselves. Two animals belonging to different species are unlikely to mate, and even if they do, they will rarely produce viable hybrids. Dobzhansky ran experiments on fruit flies that demonstrated that this incompatibility is caused by specific genes carried by one species that clash with the genes from another species.
Thesudden appearance of the major animal phyla in the fossil record during theCambrian period is called Cambrian explosion (the mother of allmacroevolutionary events).
- Database Prototyping for Evolutionary Synthesis at NESCent
Dobzhansky's ability to combine genetics and natural history attracted many other biologists to join him in the effort to find a unified explanation of how evolution happens. Their combined work, known as "The Modern Synthesis," brought together genetics, paleontology, systematics, and many other sciences into one powerful explanation of evolution, showing how mutations and natural selection could produce large-scale evolutionary change. The Modern Synthesis certainly did not bring the study of evolution to an end, but it became the foundation for future research.
The evolutionary linkbetween and humans.
KNL: I’m a big fan of philosophers of biology. David Hull, Elliott Sober, and many others have made really valuable contributions to evolutionary biology over the years. The philosopher with whom I have worked most closely is Kim Sterelny (ANU), who was a coauthor of those EES papers, and helped pioneer thinking on niche construction. However, this research project also involves several other leading philosophers, including Tim Lewens and Marta Halina at Cambridge, as well as Jonathan Birch (LSE) and Ellen Clarke (Oxford). They have a really important job to do. For instance, the recognition of multiple inheritance systems generates challenging issues concerning how we conceptualize and measure fitness, or evolutionary change. Likewise, a central claim of the EES is that developmental processes should be recognized as evolutionary processes. That raises questions like: What is an evolutionary process, and how do the structures and assumptions of the field affect what are recognized as causes of evolution? Philosophers can help biologists to think clearly about these issues, and their involvement will help promote awareness of the roles that conceptual frameworks play in science.
The next step in the evolutionary ladder is the .
DSW: Sounds very exciting! This table from your Proceedings article does a good job contrasting the core assumptions of the Modern Synthesis and the EES. In my opinion, your portrayal of the Modern Synthesis is accurate. It is the view of evolution that most people were taught and continue to teach. Against that background, the core assumptions of EES look very different indeed, even deserving the label “New Synthesis” or “New Paradigm”. Why shouldn’t the EES be described in bolder terms?
It is model organisms for the studyof the prokaryotes.
DSW: I agree with you that deep philosophical issues lie behind the seemingly innocuous phrase “Extended Evolutionary Synthesis” and I’m glad that you include a number of philosophers on your team. TVOL will be featuring them directly in future articles, but could you please provide a brief introduction to them and their role in the research program?