Geologic Time Review

Question 1

6 major events of the Precambrian era

Answer 1

1) Earth Forms
2) Surface of Earth cools, crust forms
3) 1st prokaryotes
4) Cyanobacteria produce oxygen
5) 1st eukaryotes
6) Multicellular organisms evolve

Question 2

What is the Cambrian explosion and why is it important?

Answer 2

It marked the appearance of most major animal phyla, organisms became more diverse (mostly aquatic invertebrates w/ exoskeletons)

Question 3

What is the Burgess Shale?

Answer 3

Fossil site located in Canadian Rockies

Question 4

What is the importance of the ozone layer and what did it allow for?

Answer 4

The ozone layer blocks harmful UV radiation, which allowed life to evolve on land

Question 5

What is the Mesozoic era also known as?

Answer 5

The age of the dinosaurs

Question 6

What did the first mammals look like?

Answer 6

small rodents like shrews or voles

Question 7

What happened at the end of the Mesozoic era? What is believed to have caused this?

Answer 7

MASS EXTINCTION

-A meteor impact causing Iridium dust to block out the sun and wipe out life on Earth

Question 8

What dominated Earth after dinosaurs were wiped out?

Answer 8

mammals lol yolo human 4 lyfe

Question 9

Place in order and identify the Geologic time period

• 1st vertebrates
• 1st jawed fish
• 1st land animals
• 1st bony fish
• 1st reptiles
• 1st mammals

Answer 9

1. 1st vertebrates(jawless fish)-ordovician
2. 1st jawed fish- silurian
3. 1st land animals- silurian
4. 1st bony fish- devonian
5. 1st reptiles- carboniferous
6. 1st mammals- jurassic