In the early nineteenth century, the French scientist Georges Cuvier provided conclusive evidence of the extinction of species on Earth. Although Cuvier correctly asserted that a series of catastrophes led to these extinctions, he could not provide a testable explanation of the source of the new animals and plants that appeared after the extinction of older forms. How would you argue that modern evolutionary theory provides an explanation for the proliferation of new forms of life after mass extinctions?

Because mass extinction is a natural process that may facilitate evolution during the period of thousands to millions of years that follow it, should humans be concerned about the current mass extinction we are causing? Why or why not?

What factor results evolution of a species? A) Genetic Drift B) Gene Flow C) Natural Selection

a) What is the best estimate (mean age), in millions of years, for the divergence of the clade containing the American Giant Short Faced Bear from the clade containing the Sloth Bear? b) According to Figure 1, bears as a group experienced substantial evolutionary radiation near what geological boundary? c) True or False. An entire clade of bears has gone extinct because the two extinct bear species in the figure are sister species. d) What bears are the nearest relatives of the Sun Bear?

Use the evolutionary tree below to answer the following questions:

Jean-Baptiste de Lamarck’s explanation for the evolution of long-legged giraffes from shorter-legged okapi-like ancestors migrating to a savanna would not include which of the following features? over time, inheritance of acquired characteristics in okapis would lead to savanna giraffes once an okapi had acquired longer legs, it could pass on this new trait to its offspring only those okapis with favorable traits (long legs) could be ancestral to savanna giraffes each individual okapi could increase its leg-length by deliberate, consistent exercise okapis in a savanna habitat found it advantageous to stretch their legs for treetop leaves