Evolution Geologic Time Scale Flashcards

Precambrian

(Before the Cambrian Explosion)

Lasts from Earth forming (4.54 bya) to Cambrian Explosion (540 mya)

First 4 billion years of Earth History

Life is relatively absent or very simple

(Hadean, Archean, and Proterozoic Eon)

Hadean Eon

Land is molten rock, very hot, high volcanic activity

Toxic atmosphere lacking oxygen

High rate of metor strikes

Very bad place for life to emerge

Archean Eon

Land on earth imerges from the earth cooling down

Liquid water increases covering the planet, volcanic activity forms islands

Meteor impacts slow

First life appears (3.5 bya)

Stromatolites

First life appears during the Archean Eon (3.5 bya)

Photosynthetic prokaryotes, algae

Very Simple life

Proterozoic

Plate tectonic movement cause land masses to clump into supercontinents

Atmopshere is oxygenated by photosynthetic bactera (leads to more ATP)

Eukaryotes evolve because of more oxygen, therefore allowing them to use more energy

Ediacaran Period: First multicelluar life appears

Ediacaran Period

First multicellular life appears because of greater oxygen

Phanerozoic Eon

(Paleozoic Era, Mesozoic Era, Cenozoic Era)

Start of Visible Life (Evolution)

Cambrian Explosion starts the Phanerozoic Eon

Cambrian Explosion

Start of the Phanerozoic Era, ends the Precambrian

Rapid diversicaton of life in the fossil record

No one knows why it happened, (theories: PREDATION, desire to move to land, must evolve to survive)

Paleozoic era

Age of invertabrates

From Cambrian Explosion to Great Dying

Complex life moves onto land

Mass Extinction

Estimated 75% of species die out in s ashort period of time

Caused by changes in climate

Great dying was the worst Mass Extinction

Great Dying

(70% of land and 96% of aquatic specie die out)

Took 200,000 years

Caused by increase in volcanic activity, changes in ocean chemistry

Mesozoic Era

From Great Dying to KT Event

The Age of Dinosaurs

Mammals evolved, flowering plants emerged

KT Event

mass extinction caused by a meteor impact

boundary line made of iridium,

Sun block out, lack of photosynthesis

Cenozoic Era

KT Event to Present day

Mammals become dominate animal on the planet,

First hominids emerge, turn into homo sapiens