Lesson 12) Dinosaur Extinction

Question 1

Extant Species

Answer 1

Species still alive today

Question 2

What are the 5 major mass extinctions?

Answer 2

1. End Ordovician : of marine organisms, but luckily terrestrials have began to evolve

2. Late Devonian: of Marine organisms and some early vertebrae clades

3. End Permian: of marine organisms, insects, synapsids, and anapsids

4. End Triassic: of marine organisms and pseudosuchians, synapsids

5. End Cretaceous: of marine organisms, pterosaurs, mosasaurs, plesiosaurs, plankton, ammonitesm corals, dinosaurs, and many Cretaceous birds
- Large and/or photosynthetic animals died off fastest
- Small (some of which were semiaquatic) had higher chances of survival

Question 3

Iridium

Answer 3

Rare element on Earth but is common in meteorites

Question 4

Tektites

Answer 4

Tiny pieces of rock that have been melted then cooled

Question 5

Shocked Quartz

Answer 5

Form of mineral quartz w/ unique internal structure that can only be created by exposure to a powerful shockwave (eg- nuclear explosion or meteorite impact)

Question 6

Cenotes

Answer 6

Limestone sinkholes

Was discovered to be arranged in a crescent shape many miles long near the town of chixulub, Mexico. It continued along the ocean floor.
- Caused by displaced portion of limestone layer (meteor)

Question 7

How did a single meteorite possibly cause the End Cretaceous Extinction?

Answer 7

Initial impact caused tsunamis and sent cloud of suer-heated rock/dust high into atmosphere. ROcks and debris fell, causing wildfires. Debris were heated b air friction, raising global temps immensely. Animals too big could not have taken shelter.

The debris also stayed in the atmosphere for a long time -> reduces sunlight -> kills plants, rippling effects in food chain.

Smaller animals could have taken shelter, have lower metabolisms, or scavenged.

Question 8

What are some silly goody End Cretaceous Extinction theories?

Answer 8

1. Small mammals ate eggs
   - Problem: They have been co-existing for millions of years and it doesn’t explain why other non-Amniotes didn’t survive
2. Cretaceous period immediately followed after the ice age, which froze Dino’s
   - It was a gradual temp fall
3. Dino’s releasing too much methane
4. Nearby Supernova, viral outbreak
5. Mass volcanic outgassing of CO2 fumes.
6. Climate change from plate tectonics

Question 9

On average, how long does a species last before it goes extinct?

Answer 9

1m - 10m years

Question 10

How often is Earth hit by a meteorite the size of a house?

Answer 10

Every 5 years