BIOSC 0160 Lecture Notes - Phylogenetics, Pattern Formation, Neoteny
Document Summary
E. g. feathers were originally developed for warmth, but then birds began using them for flight by happenstance. In which the modifications arise as novel phenotypes. Produced by heritable modifications of the development of the phenotype. Such that phenotypes that confer higher fitness in an environment come to predominate in that environment: van valen: evolution is the control of development by ecology, allometric growth/change in shape. Evolutionary change in rate results in different shape. E. g. humans" brains grow much faster than chimps: heterochrony. Humans" brains grow for a longer period of time than chimps" do. Juvenillization compared to ancestor species: salamanders, some never change to the adult form, look like a large juvenile tadpole forever, this is because the offset of development occurs earlier. 4/8: domestic dogs, less aggressive and more playful, juvenile characteristics, pattern formation- hox genes. Developmental establishment of precise spatial relationships between parts. Macroevolutionary events: adaptive radiation, prolific diversification within a new adaptive contest, e. g. shells in mollusks.
