History of Life

Question 1

origin of eukarya

Answer 1

3.5 billion years ago

Question 2

first organic molecules

Answer 2

• water
• methane
• ammonia
• hydrogen sulfide
• carbon dioxide
• phosphate

Question 3

bubble hypothesis

Answer 3

Waves drive bubbles into the shore
Oily (with phospho-lipids) bubbles last longer
Primitive ‘membrane’ enclosing nucleotides and exposing them to UV
Organic polymers form in the protected bubbles
Some would be better at replicating inside the bubbles than others

Question 4

clay hypothesis

Answer 4

Clay is made of silicate crystals in solution
Crystals form up in a regular structure and spontaneously ‘replicate’
Organic monomers attracted to silicate crystals
Different patterns of silicate under ‘selection pressure’
Replicating organic molecules are an exaptation
Eventually became independent of clay scaffold

Question 5

extra terrestrial theory- COMETS

Answer 5

‘Exogenesis’
In pace organic compounds are quite common
In the outer solar system volatiles don’t evaporate as there is little heat from the sun
Comets often encrusted with a ‘tar’ like substance
Could have rained down on the earth
Introduction of complex organic polymers

Question 6

Extra terrestrial hypothesis-MARS

Answer 6

Life appeared on earth very soon after it’s formation
Little time fro the crust to cool down
Mars is smaller than Earth do it cooled faster and life formed here first
Bits of Mars blasted off by asteroid impacts and arrived on earth
Introduction of complex organic polymers

Question 7

What was the catalyst for the first cell replications?

Answer 7

enzymes

Question 8

brown algae domain

Answer 8

chromista

Question 9

stromatloites

Answer 9

fossilised cyanobacteria (2-3.5 bya)

Question 10

first eukarya description

Answer 10

• large cell size
• nucleus
• organelles
• mitosis

Question 11

Opisthokonts

Answer 11

flagellat cells propelled by a single posterior flagellum

Question 12

vertebrata

Answer 12

chridates with a BACKBONE