Biotic Crisis: Past, Present...and Future

Scientists believe we are reaching a point of no return. Earth as we know it was formed over several billion years, through the working of incalculable forces. But in the past few centuries we have demolished much of the ecosystem—the structures, resources and inhabitants of Earth on which we depend. Stresses on the world’s ecological systems arise from war, agriculture and deforestation, exploitation of the deep sea, misuse of the Earth’s surface and subsurface, and the release of greenhouse gases.

We will survey the evolution of Earth, starting with the planet’s formation, taking in the growth of life and past mass extinction events, and considering the effects of human activity now and into the future.

A $62 discount will be applied automatically for adults 55+.

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What will I learn?

Week 1: Evolution of the Earth

A survey of Earth from the beginning of time—the Initial Singularity or Big Bang. Earth was formed, and became a unique place for life as the oceans appeared. As species spread throughout the oceans, some died out and some flourished.

Week 2: Extinction and evolution

Gradual changes and different ecosystems formed underwater creatures, and some became terrestrial over millions of years. Natural selection favoured species with the ability to change and adapt to the new environment.

Week 3: Natural hazards and mass extinction

Contrary to popular belief that mass extinction is a new phenomenon, Earth has, in the past, witnessed five major “biotic crises”, during which more than 75% of species disappeared. In these crises, more vulnerable species became extinct step-by-step, over tens of thousands of years.

Week 4: Examples of biotic crises

Dinosaurs had ruled the lands, and oceans had belonged to the ammonites before the most recent, Cretaceous–Paleogene (K-Pg), mass extinction. We have some evidence that shows the size of aquatic dwellers diminished during warmer conditions, with a subsequent cooling killing those dwarfs in turn, so that only the most “opportunist” species survived.

Week 5: What’s going on now?

Human activity has been increasing in resource usage and waste since the industrial revolution. During the last 200 years, excessive pressure has caused ecosystem condition deformation and many species have died out, migrated or changed their behaviour.

Week 6: What will happen next

A sixth mass extinction is underway and the Earth is going to lose millions of regional and local species. Human overconsumption threatens nature, and we will pay a high price for the demolition of this assemblage of life, unique in the universe.

How will I learn?

  • Lectures
  • Discussion (may vary from class to class)
  • Papers (applicable only to certificate students)

How will I be evaluated?

For certificate students only:

Your instructor will evaluate you based on an essay, which you will complete at the end of the course. You will receive a grade of “satisfactory” or “unsatisfactory.”

Textbooks and learning materials

Reading material (if applicable) will be available in class. Some course materials may be available online.

If you're 55+, you may take this course as part of

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