LIFESCI 1 Lecture Notes - Lecture 5: Background Extinction Rate, Spiriferida, Extinction Event
21 Jan 2015
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2 hypotheses: how clades go extinct during background extinction: hypothesis 1: gambler"s ruin , fluctuating diversity around constant b and d rates lead to. The red queen: obtained fossil record for ~40 clades of north american mammals, example: clade of fossil hyaenidae (extinct hyenas, blue line= the number of genera that are present in the fossil record through time. P value = 0. 24 saying that if there were 100 hyena clades simulated, 24 of them had an age that was equal to or less than the age of the observed hyena clade. Red dot is falling shorter than average simulated age: for hyenas, clades do not survive as long as expected if extinction is due to gambler"s ruin, but not by too much less. Does not necessarily reject gambler"s ruin: simulated distributions of expected clade ages for other species. They calculate b and d over the rise phase and over the decline phase. Rise phase: from origination to highest peak.
