Prokaryotes and Eukaryotes

Question 1

Name some evidence of early prokaryote life

Answer 1

Fossil stromatolites

Fossil microorganisms

Carbonaceous matter

Question 2

What were stromatolites colonies of?

Answer 2

Cyanobacteria

Question 3

What are the two types of fossil microorganisms?

Answer 3

Silicified in cherts

Acritarchs preserved in siltstone

Question 4

When did life roughly evolve?

Answer 4

3.45 billion years ago

Question 5

How long did prokaryotes dominate the planet?

Answer 5

2 billion years

Question 6

What were some early oxygen sinks?

Answer 6

Volcanic gases in early atmopshere react with oxygen

Dissolved iron reacts with oxygen to from BIFs (Banded Iron Formations)

Faculative aerobes

Question 7

When was the Great Oxygenation Event?

Answer 7

2.4 - 1.8 billion years ago

Question 8

What needs to be considered when thinking of the origin of eukaryotes?

Answer 8

When were conditions suitable for the origin of eukaryotes

Fossil evidence of eukaryotes

Question 9

What is some fossil evidence of early eukaryotes?

Answer 9

Some acritarchs are large enough to suggest eukaroytes ~2 billion years ago

Question 10

What are the three theories of eukaryote origin? Which has the most evidence?

Answer 10

Theory 1 - Symbiosis (ate other bacteria and became symbiotic)

Theory 2 - Elaboration of a cell membrane

Theory 3 - Multiple symbiotic events (each component of a eukaryote was a prokaryote)

Theory 3 has the most evidence

Question 11

What early prokaryote did mitochondria originate from?

Answer 11

Faculative aerobe, proteobacterium

Question 12

Why would an early eukaryote engulf an early mitochondria?

Answer 12

Early eukaryotes could not cope with higher oxygen levels so engulfed a prokaryote that could

Question 13

What early prokaryote did chloroplasts originate from?

Answer 13

Cyanobacteria

Question 14

What early prokaryote did flagella and cilia POSSIBLY originate from?

Answer 14

Spirochaete bacteria