Earth and life EXAM 4 (Unit 12/13)

Question 1

When did the Triassic period begin?

Answer 1

251M.Y.A

Question 2

when did the Triassic period end?

Answer 2

202 M.Y.A

Question 3

when did the Jurassic period begin?

Answer 3

202 M.Y.A

Question 4

when did the Jurassic period end?

Answer 4

142 M.Y.A

Question 5

squid like relatives of ammonoids

Answer 5

Belemnoids

Question 6

Functioned as important guide fossils

Answer 6

Ammonoids

Question 7

Describe the upper cretaceous seaway

Answer 7

Transgression followed by regression

Question 8

• Blunt toothed shell-crushers
• Broad armored
  bodies, looked
  like huge turtles
• Triassic only

Answer 8

Placodonts

Question 9

• Triassic only
• May be first marine reptiles
• Lifestyle like modern seals

Answer 9

Nothosaurs

Question 10

• Evolved from
  nothosaurs
  – Fully marine
  – Fed on fish
  – Existed throughout
  Mesozoic

Answer 10

Plesiosaurs

Question 11

• “Fish-lizard”
  – Similar to modern dolphins
  – Bore live young

Answer 11

Icthyosaurs

Question 12

when did Pangea begin to break up?

Answer 12

Late Triassic

Question 13

Describe the mass extinction that ended the Triassic period.

Answer 13

Global warming
– Volcanic activity released high volumes of CO2
– Number of Leaf stomates increased
* Cells that utilize CO2

Question 14

what kind of rocks forms salt domes

Answer 14

Evaporites

Question 15

what geographic feature is described?

Late Jurassic
- Global sea level rose
– Pacific flooded western
U.S

Answer 15

Sundance sea

Question 16

what formation held a large volume of dinosaur fossils?

Answer 16

Morrison formation

Question 17

thought to be melt droplets from the late cretaceous extinction event

Answer 17

Microspherules

Question 18

When did Jurassic period end?

Answer 18

142 M.Y.A

Question 19

When did the Cretaceous period begin?

Answer 19

142 M.Y.A

Question 20

when did the Cretaceous period end?

Answer 20

65 M.Y.A

Question 21

why did the sea level rise so much in the cretaceous period?

Answer 21

Sea floor spreading doubled.
- forced water upwards and flooded continents

Question 22

High Mg/Ca levels favor what precipitate?

Answer 22

Aragonite

Question 23

Low Mg/Ca levels favor what precipitate

Answer 23

Calcite

Question 24

Single-celled Phytoplankton (Algae)
SiO2 skeleton
0.01mm diameter

Answer 24

Diatoms

Question 25

• Single-celled Algae
• Plates make
  chalk
• 0.008mm

Answer 25

calcareous nanoplankton

Question 26

• Became useful biostratigraphic markers
• Calcareous protozoans ~0.5mm

Answer 26

Foraminifera

Question 27

Surface-dwelling bivalve mollusks
– Up to 1 m tall
– Formed large tropical
reefs

Answer 27

Rudists

Question 28

One of three classes of ray-finned
fishes. Today includes 20,000 species in about 40 orders.
– Dominant modern
group
– Symmetric tail
– Specialized fins
– Short jaws

Answer 28

Teleost

Question 29

describe the plant life of the cretaceous

Answer 29

Angiosperms (Flowering plants)
* Hardwood trees
– Increase in complexity and form
– Stimulated evolution of pollinating insects
– Gymnosperms still dominant
– Cycads declined

Question 30

early cretaceous record of dinosaurs is ______, late cretaceous record is ________

Answer 30

Poor/good

Question 31

what is the official state dinosaur of texas?

Answer 31

PLEUROCOELUS

Question 32

describe the scale of the mammal population during the Cretaceous

Answer 32

• continued to evolve but remained small in numbers

Question 33

when did the first herbivore mammals appear?

Answer 33

Jurassic

Question 34

describe the paleogeography of the Cretaceous period.

Answer 34

Seas opened: South Atlantic
* Mid- Cretaceous Sea level high
– Tethys Seaway
* Most continents
were isolated

Question 35

was the CO2 levels during the Cretaceous higher or lower than it is now?

Answer 35

Higher- led to a large greenhouse gas effect

Question 36

describe oceanic Anoxia events

Answer 36

deeper parts of oceans lacked oxygen
– Black organic rich
muds deposited when
seas spilled over
– Important source of oil

Question 37

subduction angle _______ beneath western US

Answer 37

decreased

Question 38

describe the direction volcanism shifted in the cretaceous compared to the Jurassic

Answer 38

shifted further inland (East) to Idaho and Nevada