Evolution__3rd_Edition

xx Full Contents
21.4.3 Ordovician trilobites show gradual evolutionary change 605
21.4.4 Conclusion 605
21.5 Evolutionary rates can be measured for non-continuous character
changes, as illustrated by a study of “living fossil” lungfish 606
21.6 Taxonomic data can be used to describe the rate of evolution of
higher taxonomic groups 609
21.7 Conclusion 611
Summary Further reading Study and review questions
22. Coevolution 613
22.1 Coevolution can give rise to coadaptations between species 614
22.2 Coadaptation suggests, but is not conclusive evidence of, coevolution 616
22.3 Insect–plant coevolution 616
22.3.1 Coevolution between insects and plants may have driven the
diversification of both taxa 616
22.3.2 Two taxa may show mirror-image phylogenies, but
coevolution is only one of several explanations for this pattern 618
22.3.3 Cophylogenies are not found when phytophagous insects
undergo host shifts to exploit phylogenetically unrelated
but chemically similar plants 620
22.3.4 Coevolution between plants and insects may explain the
grand pattern of diversification in the two taxa 622
22.4 Coevolutionary relations will often be diffuse 623
22.5 Parasite–host coevolution 623
22.5.1 Evolution of parasitic virulence 625
22.5.2 Parasites and their hosts may have cophylogenies 630
22.6 Coevolution can proceed in an “arms race” 632
22.6.1 Coevolutionary arms races can result in evolutionary
escalation 634
22.7 The probability that a species will go extinct is approximately
independent of how long it has existed 637
22.8 Antagonistic coevolution can have various forms, including
the Red Queen mode 638
22.9 Both biological and physical hypotheses should be tested on
macroevolutionary observations 640
Summary Further reading Study and review questions
23. Extinction and Radiation 643
23.1 The number of species in a taxon increases during phases of
adaptive radiation 644
23.2 Causes and consequences of extinctions can be studied in the
fossil record 646
23.3 Mass extinctions 648
23.3.1 The fossil record of extinction rates shows recurrent
rounds of mass extinctions 648
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