Bio Test

What made it possible for O2 to accumulate in the atmosphere and oceans according to the first hypothesis?

The burial of organic matter destabilizing the photosynthesis-respiration equilibrium.

What are the eons in order?

Hadean, Archean, Proterozoic, Phanerozoic.

When was the Hadean eon?

4.6-4 billion years ago.

What was the atmosphere made of during the Hadean eon?

Methane, CO2, and water vapor.

During the Hadean Eon, significant cooling caused what?

A rock crust to form.

During the Archean Eon, what happens with water?

It condenses to form oceans that cover Earth.

What introduced Fe2 into oceans?

Eroded iron and hydrothermal vents.

What oxidized the Fe2 into Fe3?

The O2 produced by cyanobacteria.

What causes banded patterns on ocean floors?

Fe3 precipitation on the ocean floor.

When did the first life forms develop?

During the Archean Eon.

What were the first life forms?

Simple anaerobic prokaryotes.

Cyanobacteria evolved during the end of which eon?

Archean Eon.

What are Cyanobacteria?

Prokaryotic cells that are able to undergo photosynthesis.

Why are Cyanobacteria important?

They started producing oxygen.

When oxygen was first created, what did it react with?

Iron in the oceans.

When does Oxygen begin accumulating in the atmosphere?

During the Proterozoic Eon.

When do the first eukaryotic cells evolve?

During the Proterozoic Eon.

When does the Boring Billion occur?

During the Proterozoic Eon.

What is the same during the Boring Billion?

Photosynthesis and respiration.

What led to O2 increase after the Boring Billion?

Dynamic continental changes, burying organic matter.

What evolved near the end of the Proterozoic Eon?

Very simple plants and animals.

What marks the beginning of the Phanerozoic Eon?

The Cambrian explosion.

What happens with oxygen during the Phanerozoic Eon?

It fluctuates and rises to 36%.

What are the 5 mass extinctions of the Phanerozoic Eon in order?

Ordovician, Devonian, Permian, Triassic, Cretaceous.

What are mass extinctions?

Period of time where over 75% of species go extinct.

How long do mass extinctions take to occur?

Thousands to millions of years.

What caused the Ordovician extinction and what happened?

The ice age - extinction of marine animals.

What caused the Devonian extinction and what happened?

Oxygen depletion - loss of fishes.

What caused the Permian extinction and what happened?

Volcanic eruption - 96% of animal species become extinct.

What caused the Triassic extinction and what happened?

Volcanism - almost all animals become extinct, dinosaurs dominated.

What caused the Cretaceous extinction and what happened?

Asteroid - extinction of dinosaurs.

What made it possible for O2 to accumulate in the atmosphere and oceans according to the second hypothesis?

The depletion of reduced compounds (Fe2).