L9 - Explosions and Extinctions

Question 1

When did Stromalites emerge again? What impact did they have?

Answer 1

3.3 mya - Cyanobacteria who used oxygenic photosynthesis

Question 2

What benefits does oxygen in the atmosphere have?

Answer 2

Ozone layer - protection from UV radiation

Enables aerobic respiration

Question 3

When did Rodinia split up?

Answer 3

750 mya - Late pre-Cambrian

Question 4

What might more landmass in Northern latitudes have done to Earth’s climate?

Answer 4

Caused glaciation - Snowball Earth hypothesis

Question 5

Over what period did trilobites live?

Answer 5

542-252 mya

- >20,000 species in 5,000 genera

Question 6

What are the principal animal taxonomic ranks?

Answer 6

Kingdom, Phylum, Class, Order, Family, Genus, Species

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Question 7

What are Lagerstatten?

Answer 7

Deposits with many fossils with exceptional preservation

- Concentration Lagersatten - Quantity fossils
- Conservation Lagersatten - Quality fossils

Question 8

Name two Cambrian Lagerstatten

Answer 8

Chengjiang, China
  - Shale
  - 525 mya - Early Cambrian
  - Shallow sea
Burgess Shale, Canada
  - Discovered by Charles Dolittle Walcott in 1901
  - 505 mya - Late Cambrian
  - Disturbed by turbidite flows

Question 9

Tell me the story of Hallucigenia

Answer 9

Initially thought to be odd stilt walking thing

Now thought to be more slik-worm like

Question 10

How long did the Cambrian explosion last?

Answer 10

80 myr