BIO372 : Extinction

Occasionally, the environment changed so radically and so fast that only those species that were already adapted to the new conditions managed to survive through the transition. The others died out.

From our vantage point in the present, it seems that the great catastrophes in geologic time happened very fast. In fact, most of the mass extinctions occurred over a period of tens, if not hundreds, of thousands of years. When conditions were right, remains of the dead were preserved as fossils. We can trace the changes that occurred in the past by examining the fossils of our ancestors and of the ancestors of other species.

With the disappearance of the dominant species during the great crises of the past, opportunities were opened for development and divergence of those that remained.

We will take a look at some of the mass extinctions in the history of the earth, look for evidence to explain how they occurred, try to identify patterns, and observe changes in certain groups of organisms.

• Mass Extinctions
• Pattern & Opportunity

After completing this module, you should be able to:

• Define a mass extinction and describe the events involved in wholesale species disappearance
• Discuss opportunities for the evolution and expansion of surviving species
• Articulate alternative hypotheses of the causes of mass extinctions
• Identify evidence which is relevant to your hypotheses
• Suggest ways to distinguish between your alternative hypotheses

To complete this module, you should:

• Read the papers for "Extinction" in the course pack.
• Open and read the hyper-text lessons for each topic in the unit, including the links in the body of each lesson.
• Submit assignments by the dates indicated on their respective pages.