Evolutionary Biology Mass Extinctions: Major turning points in biodiversity by Devin Reese, PhD. Reading Quiz Teach with this 1. Which analogy best fits the phenomena of mass extinctions to date? All the copies of a particular book getting checked out at the library. A book going out of print, thus not available at the library anymore. A library closing down entirely because of funding shortfalls. Lots of books getting ruined by a leaky roof in a large library wing. 2. How are background extinction rates relevant to the discussion of mass extinction? Species are continually going extinct a low rates, but ALL species disappear in a mass extinction. The rate of species loss during a mass extinction is much lower than the background rate. During a mass extinction, the rate of species loss is high relative to the background rate. In background extinctions, single species disappear, versus a whole group in a mass extinction. Use the image below for questions 3 & 4. image © CC-BY Hannah Ritchie (2022) 3. Looking at this figure that shows mass extinctions, what broad conclusion can you draw? Most of the species loss in mass extinctions happened since humans arrived on the scene. Most of the species loss in mass extinctions happened during the first hundred million years of life on Earth. More than half of global species have gone extinct at least five times in Earth's history. More than half of global species have gone extinct an uncountable number of times. 4. Which is the BEST description of what constitutes a mass extinction (relative to background extinctions)? A higher percentage of species went extinct within a certain period of time. A broader diversity of species went extinct within a set period of time. A wider geographic range of species went extinct over all time of life on Earth. More total types of species went extinct over all time of life on Earth. 5. Fossils of dead organisms provide a good record of extinctions since the beginning of life on Earth. true false 6. In this Figure that plots species diversity (top section) during an approximately 100 million year period alongside environmental changes, what is apparent about the end-Ordovian extinction event? CC BY-NC-ND 4.0 DEED Rasmussen et al., 2019 Several environmental changes caused the mass extinction after a precipitous rise in diversity. Two environmental changes - ocean climate and sea level - caused the mass extinction. Several environmental changes conspired to cause the mass extinction after a gradual fall in diversity. Two environmental changes - plate tectonics and carbon cycling - caused the mass extinction. 7. The causes of mass extinctions may be physical or biological. true false 8. What is the BEST evidence that volcanic activity has been a factor in mass extinctions to date? Craters under the sea Mounds of basalt rock Scattering of the rare metal iridium Discovery of quartz that has undergone shock 9. What does this impact crater in Arizona (shown in the figure below) reveal about the mass extinction that included the dinosaurs? Public Domain - USGS National Map Data Download and Visualization Services It reveals that the Chicxulub Crater wiped out all living things in its vicinity. It reveals that the Chicxulub Crater was large enough to impact most species on Earth. It reveals that when an asteroid strikes Earth, it broadly scatters dirt, which helped scientists visualize how dinosaurs were decimated. It reveals that when an asteroid strikes Earth, it leaves a shape like this, which helped scientists recognize the origin of the Chicxulub Crater. 10. What is distinct about the mass extinction that is now occurring, compared to previous mass extinctions? It is the first mass extinction event caused by organisms. It is the first mass extinction event caused by humans. It is likely to be bigger than previous extinction events, based on percent loss. It is likely to be bigger than previous extinction events, based on total species lost. Score Quiz
