A paradigm is essentially a conceptual framework of ideas, methods and explanatory principles that allows scientists to tackle the questions in their field. One such paradigm is the Modern Evolutionary Synthesis.
The Modern Evolutionary Synthesis, formulated in the 1930s and 1940s, contributed to evolutionary thought by bridging the intellectual and cultural gaps between geneticists, naturalists, and paleontologists. Its tenets were several:
- All evolutionary phenomena can be explained in a way that is consistent with known genetic mechanisms and the observational evidence of naturalists.
- Evolution is gradual and is caused by small genetic changes, recombination and natural selection. Discontinuities among species are explained as originating gradually, through geographical separation and extinction rather than saltation. However, this does not mean that the rate of evolutionary change is constant.
- Selection is the main driver of change, even if variations in fitness are slight. The object of selection is the phenotype in its surrounding environment. The role of genetic drift is equivocal.
- The genetic diversity of natural populations is a key factor in evolution, as are barriers to gene flow.
- The fossil record can be explained by extrapolating micro evolutionary observations to macro evolutionary events.
Traditionally, developmental biology was viewed as having played little role in the formulation of the modern evolutionary synthesis. The modern evolutionary synthesis has been continually developed, refined and challenged, and has led to the extension of the Darwinian paradigm of natural selection to include discoveries and concepts unknown to Darwin, such as DNA and genetics.
While the Traditional Evolutionary Synthesis is linked primarily to genetics, related work has been done in a number of fields including Engineering, physics, neuroscience and computing, that suggest that a future synthesis might be more inclusive.
- Huxley J.S. 1942. Evolution: the modern synthesis. Allen & Unwin, London. 2nd ed 1963; 3rd ed 1974.
- Mayr & Provine 1998
- Mayr E. 1982. The growth of biological thought: diversity, evolution & inheritance. Harvard, Cambs. p567 et seq.
- Pigliucci, Massimo 2007. Do we need an extended evolutionary synthesis? Evolution 61 12, 2743–2749.