So why did this one isolated population survive when all other yellow-spotted bell frogs have disappeared?

为什么当其他黄斑响铃树蛙消失时唯有这群树蛙生存了下来？

youdao

When cigarettes first appeared, they spread the way an infectious disease spreads through a previously isolated population.

香烟刚出现时，就象传染病一样，在各个人群中传播。

youdao

The study looked at breeding behaviour in an isolated population of song sparrows living in grasslands on the island of Mandarte, off the coast of Canada.

这一注视繁殖行为的研究在一个隔离的唱歌麻雀群中进行,这一麻雀群生活在远离加拿大海岸的蒙大特岛的草原上.

youdao

Many observers say those policies have contributed to creating an impoverished, undereducated and isolated population.

VOA: standard.2009.03.26

Its isolated population live just as they have for centuries, seeming half-pleased and half-snubbed at being left out of the hubbub of the neighbouring islands.

BBC: The perfect trip: The Dodecanese Islands

As part of the trial cull, researchers have trapped and euthanised sick animals two to five times a year from an isolated population in the south-east of Tasmania.

BBC: Cull 'cannot save' Tasmanian devil

It was also home to a distinct and isolated mosquito population, so the effect could be monitored closely with only a minor risk of mosquitoes from neighbouring areas contaminating the results.

BBC: The malaria parasite is spread by mosquitoes