Presentation on theme: "Evolution General Zoology, 19 January 2011 Donald Winslow Reading: Hickman et al. 2011 Integrated Principles of Zoology, 15 th ed., McGraw-Hill Ch. 1 pp."— Presentation transcript:
Evolution General Zoology, 19 January 2011 Donald Winslow Reading: Hickman et al. 2011 Integrated Principles of Zoology, 15 th ed., McGraw-Hill Ch. 1 pp 13-15; Ch. 6 pp 101-109, 111-121, 123-131 “Nothing in biology makes sense except in the light of evolution.” --Theodosius Dobzhansky
Founders of evolution Lamarck—inheritance of acquired traits Lyell—uniformitarianism & gradualism Malthus—exponential growth & limitation Darwin—natural selection, speciation Wallace—independently developed theory of evolution by natural selection & inspired Darwin to publish.
Darwin's theory of evolution Change Common descent Speciation Gradualism Natural selection
Charles Darwin Voyage on H.M.S. Beagle, Galapagos Natural selection & adaptation Population growth & limits to growth Competition and heritable variation Differential survival & reproduction Gradual adaptation & speciation Reproductive barriers & speciation
Evidence for evolution Fossil record Marine organisms on mountaintops Geological time & dating—isotope decay Evolutionary trends—horses Homology of vertebrate forelimbs (Fig 6.14) “Ontogeny recapitulates phylogeny.” - Ernst Haeckel
Flying Great Egret (Ardea alba). Photo by Karen Bays. Bird wings are homologous to a human’s arms.
Ontogeny & phylogeny Pharyngeal gill slits – Present in fish, reptiles, birds, mammals Paedomorphosis – Axolotls—salamanders that never grow up Heterochrony – Change in the timing of development
Microevolution Population genetics Gene pool Allele frequencies Hardy-Weinberg equilibrium
Allele frequencies Example with allele (T) for ability to taste phenylthiocarbamide (from Hickman, et al.) Genotype# of individualsCopies of TCopies of t T/TT/T20400 T/tT/t t/tt/t 080 10080120 p = frequency of T = 80/200 = 0.4 q = frequency of t = 120/200 = 0.6