Origins Of Life

Question 1

Give a brief timeline of earths environmental/geological history

Answer 1

Late Heavy Bombardment - 4 BYA
Banded Iron Formation - 2.5 BYA
Ozone Layer - 2 BYA
Snowball earth - 1 BYA
Anthropocene - present

Question 2

When does life begin to exist?

Answer 2

~3.5 BYA

Question 3

What triggers the oxygen crisis?

Answer 3

The emergence of cyanobacteria, after solely anaerobic life. Produces oxygen forming ozone layer.

Question 4

When did the first eukaryotes appear and when did the cambrian explosion happen?

Answer 4

~1.5 BYA

~ 0.5 BYA

Question 5

Name 7 Requirements for life

Answer 5

Liquid water
Energy source
Organic building blocks 
Biosynthetic pathways 
Separation from the environment (membranes) 
Genetic code 
Natural selection

Question 6

What are the 3 theories on the emergence of organic matter?

Answer 6

Muller-Urey hypothesis - by lighting-atmosphere reactions

Abiotic synthesis of organic molecules in hydrothermal systems

Import of organic matter from extraterrestrial sources

Question 7

Give the equation for the Miller experiment

Answer 7

NH3 + CH4 +2H2O - - - (lighting, heat, UV)–> C2H5O2N (glycine) +5H2

Question 8

What was Darwin’s theory for the origin of life?

Answer 8

Warm little pond -
“warm little pond” with ammonia and phosphoric acids formed building blocks for life
Doesn’t accommodate harsh UV conditions

Question 9

How could hot sulfur be associated with the origin of life?

Answer 9

Black smokers provided a stable environment with lower radiation
Organisms trap carbon form CO2 and obtain energy through oxidation of sulfides

Question 10

What is the RNA world theory?

Answer 10

That before DNA, RNA stored information, catalysed reactions and was capable of self-replication