TPO阅读第一篇
Speciation in Geographically Isolated Populations
第六题
According to paragraph 3, separation of subpopulations by glaciers resulted
in speciation in those groups of plants and animals that
A Were reproductively isolated even after the glaciers disappeared
B Had adjusted to the old conditions caused by the glaciers
C Were able to survive being separated from their parent population
D Had experienced some genetic divergences from their parent population
第三段是:
Geographic isolation can also proceed slowly, over great spans of time. We
find evidence of such extended events in the fossil record, which affords
glimpse into the breakup of formerly continuous environments. For example,
during past ice ages, glaciers advanced down through North America and Europe
and gradually cut off parts of populations from one another. When the
glaciers retreated, the separated populations of plants and animals came into
contact again. Some groups that had descended from the same parent population
were no longer reproductively compatible – they had evolved into separate
species. In other groups, however, genetic divergences had not proceeded so
far, and the descendants could still interbreed – for them, reproductive
isolation was not completed, and so speciation had not occurred.
答案是A
但我选D
因为原文不是写说冰河退去后，分开的物种又恢复连结
但A说Were reproductively isolated even after the glaciers disappeared
"冰河退去后 物种繁衍被孤立"
这样解释不是相反了吗?