Question

environmental change & evolution
type of organism | extinction rate (percent of species lost)
terrestrial plants | 50%
marine organisms | 95%
terrestrial vertebrates | 70%
which statement is best supported by the data in the table and in the graph?
a. sea level change was the primary reason for the permian extinction, since only marine organisms were affected.
b. sea level change was not related to the permian extinction, since sea level varies over time.
c. the increase in sea level at the end of the permian period may partly explain why the extinction rate was smaller for marine organisms than terrestrial plants.
d. the decrease in sea level at the end of the permian period may partly explain why the extinction rate was greater for marine organisms than terrestrial vertebrates.

Explanation:

• Analyze Option A: The table shows terrestrial plants (50%) and vertebrates (70%) also had extinctions, so "only marine" is wrong. Eliminate A.
• Analyze Option B: Sea level change can impact habitats (like marine ecosystems), so saying it's "not related" is illogical. Eliminate B.
• Analyze Option C: Marine organisms have a 95% extinction rate, which is higher than terrestrial plants’ 50%. The option claims marine extinction is "smaller", which contradicts the data. Eliminate C.
• Analyze Option D: Marine organisms have a 95% extinction rate (higher than terrestrial vertebrates’ 70%). A sea level decrease would shrink marine habitats, increasing extinction pressure on marine species—this matches the data and logical cause - effect.

Answer:

D. The decrease in sea level at the end of the Permian period may partly explain why the extinction rate was greater for marine organisms than terrestrial vertebrates.