Many organic compounds are ignitable, putting them in direct flame may cause fires or combustion. it is possible to start a fire on a hot plate, but typically hot plates are not heated as high and the temperature is somewhat controll-able... you can not control the temperature of a bunsen burner very easily i would not through acetone or ethanol on a hot plate, as it can catch on fire or cause burns, but it's much worse with the bunsen burner.
The answer is an overhunting.
<span>The bottleneck event means drastic reduction of the population size because of environment changes. The consequence of this is the reduction of genetic variation. The bison population is a good example of the population bottleneck. The bison population drastically reduced its size due to overhunting which culminated at the end of the 19th century, when bisons almost extinct. </span>
