Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh Edition Solomon Berg Martin Chapter 17 Introduction to Darwinian Evolution

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Terminology Evolution –Accumulation of inherited changes within populations over time Population –Group of individuals of one species that live in the same geographic area at the same time Species –Group of organisms with similar structure, function, and behavior capable of interbreeding

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Pre-Darwinian ideas Aristotle (384–322 B.C.E.) –Saw evidence of natural affinities Leonardo da Vinci (1452–1519) –Correctly interpreted fossil rocks Jean Baptiste de Lamarck (1744–1829) –First to propose that organisms undergo change as a result of natural phenomenon –Lamarck ideas discredited when Mendel’s theories rediscovered around 1900

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Darwin and evolution

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Voyage of the H.M.S. Beagle 1831 Basis for Darwin’s theory of evolution Darwin observed similarities between animals and plants –Arid Galapagos Islands –Humid South American mainland

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Voyage of the H.M.S. Beagle

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Influences on Darwin Principles of Geology by Lyell Artificial selection –Breeders developing many varieties of domesticated animals in a few generations –Plant varieties, such as kale and broccoli, developed from wild cabbage Ideas of Thomas Malthus –Population growth not always desirable –Population increases geometrically; food supply increases arithmetically

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Artificial selection in chickens: “Big Bird”

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Artificial selection in Brassica oleracea

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Evolution occurs by natural selection Adaptation –Inherited variations favorable to survival persevere –Unfavorable variations are eliminated

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Genetic variation in emerald tree boas

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Theory of evolution by natural selection Proposed by both Darwin and Wallace Based on four observations –Genetic variation exists among individuals –Reproductive ability of species causes its populations to geometrically increase –Organisms compete for resources –Offspring with most favorable characteristics is most likely to survive

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Synthetic theory of evolution Began in 1930s and 1940s Combines principles of Mendelian inheritance and natural selection –Mutation provides genetic variability on which natural selection acts –Incorporates expanding knowledge in genetic, systematics, and other scientific fields

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Wing size in female fruit flies

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Evidence for evolution from fossil records Direct evidence of evolution comes from fossils Evidence shows progression from earliest unicellular organisms to organisms of today Shows life has evolved through time

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Exposed layers of sedimentary rock

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Fossils develop in different ways

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Fossil intermediates in whale evolution

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Determining the age of fossils: radioisotope decay

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Evidence for evolution from comparative anatomy Homologous features –Derive from same structure in common ancestor Homoplastic features –Similar functions in distantly related organisms demonstrates convergent evolution Vestigial structures –Remnants of structures indicating adaptation

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Homology in animals

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Homology in plants

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Homoplasy

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Convergent evolution: mammals who eat ants and termites

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Vestigial structures

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Biogeography Study of past and present geographic distribution of organisms Continental drift has played a major role in evolution

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Continental drift

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Evidence for evolution from developmental biology Proteins and DNA contain record of evolutionary change Phylogeny –Evolutionary history of group of related species Phylogenetic trees –Diagrams showing lines of descent based on molecular data

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Phylogenetic tree of whales and their closest living relatives

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Evolutionary hypotheses tested experimentally Reznick and Endler Differences in predation correlated with differences in guppies –Male coloration and behavior –Life history traits

Copyright © 2005 Brooks/Cole — Thomson Learning Biology, Seventh EditionCHAPTER 17 Introduction to Darwinian Evolution Experimental evidence of natural selection in guppies