Slide 1Slide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Slide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Click to edit Master subtitle style 1/12/13 Chapter 14Macroevolution: the long run1/12/13 Microevolution and macroevolution•Microevolution: evolution occurring within populations–Adaptive and neutral changes in allele frequencies•Macroevolution: evolution above the species level–Origination, diversification, and extinction1/12/13 Interplay between speciation and extinction determines diversityD1 (diversity) + originations – extinctions = D2 (new diversity)1/12/13 Calculating rates of origination and extinction1/12/13 Diverse taxa have higher origination rate than extinction rateα = origination rate; Ω = extinction rate1/12/13 Extinction rate often tracks origination rate1/12/13 Causes of decline in diversity•Diversity can decline when extinction increases or origination decreases–Drop in origination rate contributed to dinosaur extinction1/12/13 Key Concepts•Extinction occurs when the last member of a clade dies–Can be species or group of species•Mass extinction in a clade can have two causes:–Drop in origination rate–Increase in extinction rate1/12/13 Biogeography: the study of geographical patterns of diversity1/12/13 Map of biogeographical regions1/12/13 Clades can become isolated through vicariance1/12/13 Marsupials evolved through a mix of vicariance and dispersal1/12/13 Key Concepts•Biogeography is a multidisciplinary field that explores the roles of geography and history in explaining the distribution of species1/12/13 Estimating diversity through time is a complicated task1/12/13 Chance fluctuations in diversity can produce trend-like patterns1/12/13 Some ecological marine communities have become more diverse1/12/13 Three “evolutionary faunas”1/12/13 Caveats to diversity studies•Most taxa studied are not species–Assignments to higher taxonomic groups somewhat arbitrary•Phylogenetic relationships among groups uncertain•Large-scale patterns may obscure interesting regional patterns1/12/13 Adaptive radiation in Hawaiian honeycreepers1/12/13 Phylogenetic signatures of adaptive radiation1/12/13 Adaptive radiation and convergent evolution1/12/13 Adaptive radiation of animals1/12/13 Fossil record reveals how major transitions occurred1/12/13 Rapid diversification of animals corresponds to major environmental changes•Warming and retreat of glaciers•Oxygenation of ocean1/12/131/12/13 Key Concepts•Most adaptive radiations involve exploitation of environments not occupied by competitors•Key innovations can transform how organisms interact with their environment–Paves the way for adaptive radiation1/12/13 Pace of extinctions•Background extinction: the normal rate of extinction for a taxon or biota•Mass extinction: a statistically significant increase above background extinction rate1/12/13 Five large mass extinctions1/12/13 Mass extinction can result from climate change1/12/13 Rising carbon dioxide from volcanic activity may have led to Permian extinction1/12/13 K-T boundary extinction may have been caused by asteroid impact1/12/13 Traces of impact along Mexican coast1/12/131/12/13 Key Concepts•The big five extinctions had different causes that impacted different organisms1/12/13 Humans may be driving a sixth mass extinction1/12/13 Habitat loss contributes to extinction1/12/13 Current extinction rates are on par with previous mass extinctions1/12/13 Increasing carbon dioxide leads to warming temperatures1/12/13 Increasing carbon dioxide acidifies the ocean1/12/13 Key Concept•Although a single extinction event may have minimal impacts on an ecosystem a mass extinction can have cascading