Final answer:
The most likely number of amphibian and reptile species on a 1000 square mile island in the Caribbean would be 10-20 species.
Step-by-step explanation:
Based on the information provided, it is difficult to give an exact number of amphibian and reptile species that would be found on a 1000 square mile island in the Caribbean. However, we can make an educated estimate based on existing data. According to Figure 47.3, the average number of amphibian species is around 16-20 for a similar-sized area. Therefore, the most likely number of amphibian and reptile species on the island would be 10-20 species.