To determine the best explanation supported by the population data presented, we need to analyze the trends in the population sizes of these animals over the specified period (from 1990 to 2000).
Here are the key details provided in the chart:
1. Cheetahs: The population decreased from 100,000 in 1990 to 47,000 in 2000.
2. Zebras: The population decreased from 50,000 in 1990 to 7,500 in 2000.
3. Lions: The data for lion populations in 1990 and 2000 is incomplete.
Given these population trends, let's review each provided explanation in detail:
1. Explanation 1: Lion and cheetah populations compete for the food source of zebras, and lions outcompete cheetahs.
- This explanation suggests that lions and cheetahs are both dependent on zebras as a food source, and the competition results in lions outcompeting cheetahs.
- However, the data indicates that the cheetah population decreased over the 10 years, without specifying lion population trends.
2. Explanation 2: The dwindling zebra population has led to the decline of the predator lion and cheetah populations.
- This explanation states that a significant decline in the zebra population, which is a major food source, caused the decline in both predator populations.
- The provided data supports this explanation well: the zebra population drastically decreased from 50,000 to 7,500, implying that the reduced food availability likely contributed to the decline in cheetah population from 100,000 to 47,000.
3. Explanation 3: Overhunting of lion and cheetah populations has led to a decline in the food source population.
- This explanation suggests that overhunting of predators led to a decrease in their food sources (zebras).
- There is no specific information or data suggesting overhunting as a significant factor affecting lions and cheetahs directly. The drastic decrease in zebra population is more likely due to another cause.
4. Explanation 4: Lion and cheetah populations compete for the food source of zebras, and cheetahs outcompete lions.
- This explanation is similar to Explanation 1 but suggests cheetahs outcompete lions.
- Again, we lack complete data on lions to make this conclusion, and it doesn't clearly explain the decline in zebra population.
Based on the observations and trends in the population data:
- The zebra population experienced a significant decline.
- The cheetah population also saw a notable decline, which is consistent with the impact of a reduced food source.
Hence, the explanation best supported by the numbers in the chart is:
The dwindling zebra population has led to the decline of the predator lion and cheetah populations.
So, the correct answer is:
The dwindling zebra population has led to the decline of the predator lion and cheetah populations.
