BIOL 1F90 Lecture 15: BIOL 1F90 lecture 15 winter 2016
25 Feb 2016
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Document Summary
Gradualism: each new species evolves continuously, large phenotypic di erences that produce new species are due to the accumulation of many small genetic changes. Species in equilibrium for long periods and then short rapid bursts of change. Compares the development of di erence organisms in an attempt to understand ancestral relationships between organisms and the developmental mechanisms that bring about evolutionary change. Involves the discovery of genes that control development. Changes in developmental genes a ect traits that can be acted on by natural selection. Due to di erences in expression of two cell-signalling proteins. Bpm4: causes cells to undergo apoptosis and die. Gremlin: inhibits the function of bpm4 and allows cell to survive. Mutations on the expression of bpm4 and gremlin provided variation. In terrestrial settings, non webbed feed are an advantage. In aquatic environments, webbed feet are an advantage. Natural selection would have favoured webbed feet. Speciation may have been promoted by geographical isolation of habitats.
