Question

question 3(multiple choice worth 2 points)
(05.02a mc)
estimates of current rates of extinction
suggest that rates of extinction have globally decreased, but have locally increased
suggest that one - half of all animal and plant species may be gone by the year 2100
indicate that rates may be greater than the background extinction rates seen in the fossil records
indicate that rates of speciation equal extinction, so an equilibrium has been reached

Explanation:

To solve this, we analyze each option:

• Option 1: Current extinction rates are generally increasing globally, not decreasing, so this is incorrect.
• Option 2: While extinctions are a concern, the "one - half by 2100" is not a widely accepted estimate from standard extinction rate studies, so this is incorrect.
• Option 3: Background extinction rate is the normal rate of extinction without human influence. Current extinction rates (due to human activities like habitat loss, climate change) are estimated to be much higher than the background extinction rates seen in fossil records. This is a key concept in conservation biology and ecology.
• Option 4: Currently, extinction rates are much higher than speciation rates, so there is no equilibrium; biodiversity is decreasing, so this is incorrect.

Answer:

C. indicate that rates may be greater than the background extinction rates seen in the fossil records