The current taxonomic hierarchy is based on the ideas of , whose hierarchical classification scheme made a lasting contribution to systematics.

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Which of the following is caused by reproductive isolation within a species? a. a decrease in gene flow b. an increase in genetic flow c. a decrease in genetic drift d. an increase in gene flow

Which material is commonly used as a culture medium for living cells