Chapter 12: Earth's Evolution Flashcards
The Precambrian History is broken down into what three Eon groups?
Hadean
Archean
Proterozoic
Precambrian History
88% of earth’s history
or
the first 4 billion years of earth.
Hadean, Archean, and Proterozoic creation?
- particals melting, formed volcanic island arcs
- crustal fragments collided and accreated to form large crustal provinces
- larger crustal areas assembled into larger rocks, cratons. the core of modern continents
What are ancient Continental Crust?
Shields and platforms
What is a Shield?
large, relatively flat ancient metamorphic rock w/ stable continental interior
What is a platform?
Shields which are covered by sedimentary rock
What is a carton?
a Shield + a Platform
What is a super continent?
large landmasses that all consist of all, or nearly all, exciting continents
The most recent supercontinent
Pangaea
The slitting and reassembling of former subcontinents have generated what?
Most of earth’s mountain belts
What is the Supercontinent Cycle?
The idea that huge groups of land masses come together, break up, and are later recreated in a different orientation and formation….
ALL a result of sea-floor spreading!
Creation and break-up of supercontinents changes what?
wind patterns and ocean currents
The three Phanerozoic Eras?
Cenozoic (recent life)
Mesozoic (middle life)
Paleozoic (ancient life)
Pangaea began to be assembled in what Era?
Paleozoic Era (542 mya)
The breakup of Pangaea began where?
westward moving North American plate began to override the Pacific plate
Resulted in crustal deformation along western margin of NA.
Formed Sierra Nevada and Rocky Mountains
When did the Mesozoic Era occur and what periods does it consist of?
248-65 mya
Triassic
Jurassic
Cretaceous
When did the Cenozoic Era take place and what periods and epochs are in it?
65 mya-present day
Period 1: Tertiary
Epochs:
Paleocene, Eocene, Oligocene, Milocene, and Pliocene (old-young)
Period 2: Quaternary
Epochs:
Pleistocene and Holocene
Isostatic uplift of Appalachians occur due to?
Erosion
The Cenozoic Era?
(65 mya- present)
North America above sea level
US west coast was an active tectonic boundary
What happens in the Pre-Cambrian period?
First known organisms appear.
What are Stromatolites?
a. layered fossilized mounds of the bacteria: Cyanobacteria
b. Formed in shallow water
c. Provide ancient records of life on Earth
What period has the first appearance of life forms with hard parts, such as shells?
Paleozioc
During the Paleozoic, organisms diversified dramatically.. how?
- Insects and plants moves to land
- Lobe-finned fishes became 1st amphibians
(Devonian)
Footprints in the mud (now mudstone) were called what?
Allosaurus
At the Mesozoic period, many reptile groups became extinct because of what?
A large asteroid that impacted in the Gulf of Mexico
In the Cenozoic, mammals replace the reptiles as the dominant vertebrate life forms on land; called what?
Age of the Mammals
The two main mammals groups that formed in the Cenozoic?
Marsupials
placentals
When did Mammoths become extinct?
the last ice age (Pleistocene Epoch); they are related to modern elephants
The Cenozoic flowering plants is called? And what did it do?
“Age of Flowering Plants”
A) called Angiosperms
B) Influenced evolution of birds and herbivores
