EEMB 131 Lecture Notes - Lecture 15: Null Hypothesis, Lineage Ii
1 Mar 2018
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So some species have persist for a long time. Simpson (older model): result of key innovation-> made their ancestors better competitor-> result in radiation of offspring time. Species number have increase, but can"t observe if the number of niches have increased. Pattern of early diversification but also early loss. Those that survive are due to random chance/ luck. Only about 1/3 of species will persist according to the model (graph 3 on page 2) Correlate with the fossil record-> validating the null hypothesis. Why do these lineages tend to occur during the 1st 5-10 my? (page 2 of handout) Species origination highest when number of species is high because origination is a rare event. The likelihood of uncommon event (origination) occurs and them persisting. At equilibrium, origination is likely to happen but can"t persist. ** this model only worked in a space-filling/ bounded area** Many phyla don"t show effect of mass extinction.
