Exam 15: Extinction and Evolutionary Trends

Which mass extinction led to the disappearance of the dinosaurs?

You are a paleontologist studying the fossil marine fauna immediately after the K-T mass extinction.You find ammonite fossils in the post-K-T layer even though ammonites are believed to have vanished in the K-T 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?

What is the hallmark trait of aquatic organisms that survived the Permian extinction?

Explain how the figure below suggests that extinction probability is independent of a taxon's age.Keep in mind that the y-axis is measured on a logarithmic scale.

Which of the following conditions favor(s)fossilization?