Part C: Rates of Speciation and Extinction Learning objective: Use mathematical calculations to examine/evaluate trends in macroevolutionary change. Question(s): Calculate and graph the turnover rate for each time period in Figure 14.7. Geological stages A B C D Oldest known fossil of a species Youngest fossil of a species Older Time Younger Zimmer/Emlen, Evolution: Making Sense of Life, 3e, © 2020 W. H. Freeman and Company Figure 14.7 Question 1. Has there been a constant rate of turnover during each of the time periods indicated in Figure 14.7? Question 2. Why might the rate of turnover be important in evaluating diversity and extinction events?
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7? To answer this question, we need to analyze the fossil record in Figure 14.7 for each geological stage (A, B, C, and D). The turnover rate is related to the number of species that appear (originate) and disappear (become extinct) within a given time period. In Show more…
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The origination and extinction patterns of species in a clade are shown in the graph. Each horizontal line represents a single species. The starting point of a line is the origination of a species, and the end point of the line is the extinction of the species. Three geological stages are shown, A, B, and C. Geological stages Older Younger Time Calculate species turnover for stages B and C. Stage B turnover: species Stage C turnover: species Turnover is similar between Stages B and C, but the cause of the similarity varies between the stages. Stage B has many, whereas Stage C has many.
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The origination and extinction of species is shown in the graph, which spans 12 million years. Each horizontal line represents a single species. The starting point of a line is the origination of a species, and the end point of the line is the extinction of the species. Four geological stages are shown, A, B, C, and D. Geological stages A B C D Oldest known fossil of a species Youngest fossil of a species Older Younger Time Calculate the rate of origination, α, per million years from stage A through D. Provide the rate to two decimal places. α: species per million years Calculate the rate of extinction, Ω, per million years for this clade from stage A through D. Provide the rate to two decimal places. Ω: species per million years
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