Major Evolutionary Trends

摘要: Palaeontological data are essential for determining patterns of biological diversity through geological time, enabling the investigation important macroevolutionary events such as mass extinctions and explosive radiations. Most studies utilise proxies taxonomic diversity. A more complex undertaking is to assess morphological variety (disparity) revealing manner in which groups evolved their ‘design space’. Many published indicate clades tend reach maximum disparity early evolutionary history. Whether this a real pattern has yet be tested. Chapter 1 tackles evolution metazoans across Phanerozoic. The results meta-analysis 98 extinct high most prevalent Phanerozoic but finds no clear trends Mass extinction ended were exception, tending result late disparity. Chapters 2-4 focus on clade Bivalvia analysis. Bivalves ecologically taxonomically diverse have an excellent fossil record not been scrutinised using latest techniques, untouched by 2 uses up date stratigraphic ranges techniques revise bivalve curve. show robust sampling biases examined. 3 provided part collaboration between Martin Hughes, Dr Joseph Carter (University North Carolina) Matthew Wills Bath) address bivalves Palaeozoic. find rises time decreased extinctions. 4 conducts first large scale analysis latitude. that latitude unchanging stable compared steep gradient