Researchers hypothesized that a decline in the population of dusky sharks near the mid-Atlantic coast...
Researchers hypothesized that a decline in the population of dusky sharks near the mid-Atlantic coast of North America led to a decline in the population of eastern oysters in the region. Dusky sharks do not typically consume eastern oysters but do consume cownose rays, which are the main predators of the oysters. Which finding, if true, would most directly support the researchers’ hypothesis?
- A) Declines in the regional abundance of dusky sharks
- B) Eastern oyster abundance tends to be greater in areas with both dusky sharks and cownose rays than in areas with only dusky sharks.
- C) Consumption of eastern oysters by cownose rays in the region substantially increased before the regional decline in dusky shark abundance began.
- D) Cownose rays have increased in regional abundance as dusky sharks have decreased in regional abundance.
Correct Answer: D) Cownose rays have increased in regional abundance as dusky sharks have decreased in regional abundance.
Explanation
The finding that would most directly support the researchers' hypothesis is: D) Cownose rays have increased in regional abundance as dusky sharks have decreased in regional abundance. The researchers' hypothesis states that the decline in dusky shark population led to a decline in the population of eastern oysters. The reason for this decline is that dusky sharks do not consume eastern oysters but prey on cownose rays, which are the main predators of the oysters. If it is true that cownose rays have increased in regional abundance as dusky sharks have decreased, it would support the researchers' hypothesis. The increased abundance of cownose rays, which are the predators of eastern oysters, could result in a decline in the oyster population as the dusky shark population declines. Therefore, choice D is the finding that directly supports the researchers' hypothesis.