Embryological evidence, suggesting from common features in development that adults had common ancestors, was an important part of Darwin's evidence for evolution. However, over-interpretation of the evidence brought the linkage between development (ontogeny) and evolution (phylogeny) into disrepute, till Gould resurrected the field with his "Ontogeny & Phylogeny" (1977). The more recent discovery that the genes which determine pattern in early development show a high degree of homology across the animal kingdom has made the link between development and evolution (often called 'evo-devo') one of the hottest topics in evolutionary biology. In this session we will cover: the history of the link between development and evolution; the concept of phylotypic stages; an outline of pattern-forming processes in embryos; the evolution of body plans in animals; how the developmental system generates novelty in evolution - timing changes; correlated progression; the concept of development constraints in evolution.
Some valuable preparatory reading (all available in the course box-file) is:
Gilbert, S.F. (1997). 'Developmental Biology' (5th edition) Chapter 23.
Hall, B.K. (1996). Baupläne, phylotypic stages and constraint: why are there so few types of animals? Evolutionary Biology 29, 215-52.
Erwin, D. et al. (1997). The origin of animal body plans. American Scientist 85, 126-137.
At the end of this session, you should be able to: