Two hundred years ago, miners would take caged canaries into coal mineshafts as they worked.
Being smaller, the canaries would succumb to odorless, toxic gases before the gases would affect
humans. As the miners worked, they watched the canaries. If the canaries suddenly died, it was a
warning for miners to leave the mineshaft.
37.
Form an analogy between the canaries used in coal mines and the lichens living in tundra
ecosystems. Be sure to use and define the term bioindicator in your response.
