Ch. 6 Flashcards

1
Q

3 lines of evidence to consider for evolution

A

Stromatolites, microfossils, isotopic evidence

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2
Q

Stromatolites are?

A

Distinctively layered rocks with living microbes interweaved with sediments

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3
Q

Stromatolites date life to how many years ago

A

3.5 billion

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4
Q

What suggests that a form of life must predate stromatolites

A

Photosynthesis

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5
Q

Microfossils are?

A

Very tiny fossils

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6
Q

Microfossils give evidence dating back to how many years ago?

A

3.0 billion

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7
Q

Isotopic evidence is?

A

Life tends to assimilate carbon-12 atoms more easily than carbon-13

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8
Q

Isotopic evidence gives evidence dating back how many years ago?

A

3.85 billion

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9
Q

Why is it likely that life originated in water?

A

No oxygen in the early atmosphere allowed for harsh ultraviolet radiation

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10
Q

What are the three possible ways simple organic chemicals manifested?

A

From space, near the surface of the earth, deep in the ocean

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11
Q

The Miller-Urey experiment?

A

Mimicking the water cycle with lightening. Created amino acids and other organic compounds were found to exist.

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12
Q

How did life come from outer space?

A

Asteroids and comets contained amino acids and chemicals that can survive to the surface

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13
Q

What is Panspermia

A

The relocation of life from elsewhere in the universe to Earth

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14
Q

What must life survive to meet the criteria for Panspermia

A

Initial impact on other planet, harsh space, impact on earth

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15
Q

Abiogenesis

A

How life starts from the basic organic chemicals

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16
Q

RNA World hypothesis

A

RNA came before DNA

17
Q

Organic molecules formed from

A

RNA forming on clays, RNA replicates in pre-cells, complexity increases to form life, DNA evolves

18
Q

Anaerobic

A

Organisms that don’t need oxygen

19
Q

The history of evolution starting on earth

A

Simple anaerobic organisms that developed rapidly in complexity shorty after the earth formed, diversification lead to RNA. Photosynthesis generated oxygen in the atmosphere. Oxygen based life forms dominated

20
Q

Bacteria

A

single cell organisms that have no cell nucleus

21
Q

Early life was in the form of?

A

Single cell organisms that reproduced only by cell division

22
Q

Two superkingdoms began before one

A

Archea and Bacteria came before Eukarya

23
Q

Eukarya are different from bacteria and archea

A

Only cells with a nucleus and are capable of more complex reproductive strategies

24
Q

Sexual reproduction led to

A

A huge increase in the diversity of life and the rate of evolution due to genetic mixing

25
Animal life began prolific when
1.2 billion years ago
26
Reasons for explosion in Cambrian era?
oxygen level reached current levels, climate change, genetic diversification, predator efficiency was lacking
27
Plants appear in fossils how many years ago
475 million
28
What is essential for the development of atmospheric ozone
O3
29
When did the "Great Oxidation Event" occur
2.35 billion years ago
30
What is the evidence for the asteroidal extinction of dinosaurs
Large 10km diameter wide asteroid hitting the earth depositing iridium
31
Where did the asteroid hit?
Yacatan Peninsula
32
What were the ramifications of the impact of the asteroid that killed the dinosaur
Pushed material into the atmosphere causing global winter, tsunami, global fires, intense heat, reduced sunlight, mammals rose to dominance
33
Causes for extinction
Volcanic eruption, climate change, mutation, magnetic pole reversal, proximity to a supernova explosion, impact of gamma ray bursts