What does CATASTROPHIC mean?

Catastrophic Events in Earth’s History

Journal Entry #7: Here Today! Gone Tomorrow! Looking at Earth’s history, there have been five major mass extinctions over the past 500 million years. Each one is thought to have annihilated anywhere from 50 to 95% of all species on the planet. Organisms are still becoming extinct today, and it has been recorded that during the last 200 years more than 50 species of birds, more than 75 species of mammals, and hundreds of other species have become extinct.  Explain how the term mass extinction is different from extinction.  What are some possible explanations of the mass extinctions that have occurred in Earth’s past?

Mass Extinction …is a time period during which there is an especially high rate of extinction of species that occurs very quickly, typically totally 50% or more of the existing species.

It’s normal for a species to go extinct, and an average rate of one a year is the natural background rate. But over the past 4.5 billion years, there have been times when extinctions occurred at 100-1,000 times faster – with the largest event wiping out 95% of all species. Somewhere between 5 and 20 such mass extinctions have occurred.

The Big Five  Cretaceous-Tertiary “K-T” (65 million years ago)  Triassic-Jurassic ( 200 million years ago)  Permian-Triassic (250 million years ago)  Late Devonian (360 million years ago)  Ordovician-Silurian (444 million years ago)

Reading for Information (ACC) PURPOSE: 1. To look at the claims of possible causes of mass extinctions in Earth’s past, and to see if there is any scientific evidence to support them. 2. To see how mass extinctions impacted Earth’s surface, atmosphere, climate, and life.

Directions (ACC) Read and annotate the article on possible causes of Earth’s mass extinctions. Think about- 1. How did this claim cause a mass extinction. 2. Is there any evidence to support the claim happened in the past? If so, what is it? 3. Explain how it impacted Earth’s surface, atmosphere, climate, and life. 4. Could this claim happen in Earth’s future? Complete the graphic Organizer. Be prepared to discuss in Class!

Reading for Information ® PURPOSE: 1. To look at the claims of possible causes of mass extinctions in Earth’s past, and to see if there is any scientific evidence to support them. 2. To see how mass extinctions impacted Earth’s surface, atmosphere, climate, and life.

Jig-sawing Activity Directions ® Read the slip of the claim your table group has been assigned and discuss it. 1. Identify how scientists think your claim caused a mass extinction. 2. Explain how it impacted Earth’s surface, atmosphere, climate, and life. 3. Identify if there is any evidence to support your claim. If there is evidence, what is it? 4. Could this claim happen in Earth’s future? Be prepared to explain to the class …NOT reading for slip of paper!

What did we learn? ®  Complete the graphic organizer as each table group shares what they learned about their claim.  By the end of reporting out, you should know… ~ what the different claims to mass extinctions in Earth’s past are, and what evidence supports them if any exists.

Brain Pop: Mass Extinctions

Reflection Based on our discussion of possible causes of mass extinctions, can you explain how Earth’s surface, atmosphere, climate and life were impacted, and support each one with evidence.

Journal Entry #8- Could there be another mass extinction on our planet…a 6 th Mass Extinction??? What do you think and why? What would be and why? What would be the cause if one occurred? the cause if one occurred?

Could there be another mass extinction on our planet?  Watch the following video to see if your answer changes. What do you think?  ltUIsnrQ ltUIsnrQ