如果这些其他物种的种群数量增加，蜱类捕获细菌的数量就会减少，因此感染莱姆病的人数就会减少。
If the population of these other species were increased, the number of ticks acquiring the bacterium and hence the number of people contracting Lyme disease would likely decline.
这个故事讲述的是恢复了种群数量的小狐狸，以及一生致力于保护灰狐的人类。
This is the story of the little fox that has come back, and the people who have dedicated their lives to protecting it.
再假设，种群迁往一个地方——如尼罗河上游，那里的人的特点是身材高大。
Suppose this population migrates to a region, like the Upper Nile, where it is an advantage to be very tall.
应用推荐