Let's approach this step-by-step using the data provided in the chart:
1. Population Declines:
- Lions: In 1990, there were 100,000 lions. By 2000, this number had decreased to 47,000.
[tex]\[ \text{Decline of Lions} = 100,000 - 47,000 = 53,000 \][/tex]
- Cheetahs: In 1990, there were 50,000 cheetahs. By 2000, this number changed to -7,500. This number seems unusual, possibly a typo for 7,500.
[tex]\[ \text{Decline of Cheetahs} = 50,000 - \text{(-7,500)} = 50,000 + 7,500 = 57,500 \][/tex]
- Zebras: In 1990, there were 15,000 zebras. By 2000, this number had decreased to 2,500.
[tex]\[ \text{Decline of Zebras} = 15,000 - 2,500 = 12,500 \][/tex]
2. Assessing the Declining Patterns:
- Lions and cheetahs both experienced a significant population decline over the 10-year period.
- Zebras, a potential food source for these predators, also saw a substantial population decrease.
3. Analyzing the Explanations:
- Option 1: "Lion and cheetah populations compete for the food source of zebras, and lions outcompete cheetahs."
- If lions outcompeted cheetahs, we might expect the lion population to be stable or increase while cheetahs decline. This is not supported by the data which shows both predator populations declining.
- Option 2: "The dwindling zebra population has led to the decline of the predator lion and cheetah populations."
- This is supported by the data. As the number of zebras (prey) decreased, both lion and cheetah populations (predators) fell due to a reduced food source.
- Option 3: "Overhunting of lion and cheetah populations has led to a decline in the food source population."
- If overhunting of lions and cheetahs were the primary factor, we would expect the zebra population to possibly increase due to reduced predation pressure. This is not the case since zebra populations decreased.
- Option 4: "Lion and cheetah populations compete for the food source of zebras, and cheetahs outcompete lions."
- Similar to Option 1, if cheetahs outcompeted lions, the cheetah population might be stable or increase while lions decline. Again, both predator populations experienced declines, which does not support this option.
Given these assessments, the best explanation supported by the numbers in the chart is:
The dwindling zebra population has led to the decline of the predator lion and cheetah populations.
