Exam 15: Extinction and Evolutionary Trends

Which statement best describes the chain of events that indirectly led to the near extinction of Urocyon littoralis (island fox) in Roemer et al.'s 2002 study?

Which of the following is the greatest known mass extinction to date?

Approximately what percentage of marine species was lost during the Permian extinction?

Why would a paleontologist new to his or her profession who has decided to study human origins choose to focus his or her field work in Africa?

Why are endemic species particularly at risk of extinction as a result of global climate change?

What factors help a paleontologist select sites for research?

What kinds of evolutionary trends are represented by each of the two diagrams below? The x-axis represents an arbitrary scale for a trait value, in this case eyespot diameter on a butterfly's wing. A B

Describe the example of indirect effects on extinction studied by Roemer et al. (2001) in California's Channel Islands.

What particular trait made it more likely for a species to survive the Permian mass extinction?

While studying a group of ammonites (an extinct lineage of cephalopods) that lived during the Mesozoic, you measure the shell diameter of different fossil ammonite species. The table represents the data you collected for each of six different time periods. To what rule does the data conform? Time interval Mean shell diameter (+/- standard error ) 245-214 MYA 15(+/-5) 215-184 MYA 21(+/-7) 185-154 MYA 36(+/-12) 155-124 MYA 63(+/-21) 125-94 MYA 72(+/-24) 95-65 MYA 84(+/-28)

You are a paleontologist studying the fossil marine fauna immediately after the K-Pg mass extinction. You find ammonite fossils in the post-K-Pg layer even though ammonites are believed to have vanished in the K-Pg extinction. You submit your sensational findings to a journal, but one of the reviewers questions your claim of ammonite survival. He points to the fact that your ammonite fossil was found in rock that shows extensive burrowing activity by benthic organisms. Why does the reviewer question your conclusion?

The K-Pg extinction was likely the result of a catastrophic asteroid impact that resulted in an extinction that happened over a very short geological time period. How could the K-Pg impact cause the collapse of the global food chain that led to this mass extinction?

For much of the Cretaceous, bivalves belonging to the Inoceramidae were among the most prominent bottom dwellers in aquatic communities, but then declined at the end of the Cretaceous, eventually going extinct. What does the figure tell us about the reason(s) the inoceramid species went extinct?

Where would you place the actual extinction date of a taxon if you knew that the Signor-Lipps effect was at work?

Why do paleontologists find many more fossils of skeletal structures than remains of soft tissues?

The graph shows the extinction rates for families of marine organisms over different periods of Earth's history. What is the best estimate for the background extinction rate given these data?

Native plant A is endangered. You suspect that part of the reason for its decline is competition with an introduced exotic plant, B, which occupies a similar ecological niche. Which of the following experiments would NOT help you decide whether competition with B contributes to the decline of A?

The figure below shows the increasing morphological complexity in crustacean legs in 12 different phylogenetic comparisons. Why did the authors of this study choose to analyze the data independently for each comparison?

What effect of mass extinctions is described by the expression "dead clade walking"?

Alison Boyer (2008) analyzed data on the extinction of native birds in the Hawaiian Islands, particularly looking at extinctions resulting from two waves of human colonization. How did the patterns of extinction differ? A B C D