Lecture 21: Origin of Life: Environments

Question 1

what are the basic requirements for an origin of life?

Answer 1

an energy source

a means of concentrating molecules

an environment conductive to complex molecules and their assembly

some selection pressure for the origin of evolution

Question 2

why are hydrothermal vents a location favoured for the origin of life reactions, and what is some evidence of this with reference to the iron-sulfur world?

Answer 2

due to their unique combination of chemical richness, energy sources, and protective environment

iron-sulfur world proposes that iron sulfide minerals near vents catalysed early life reactions

carboxylic acids react with ammonia to produce amino acids

the surfaces of these particles also give an environment for reactions of HCN and related molecules to yield precursors to the nucleobases

Question 3

what is one other location thought to be a potential origin of life and why?

Answer 3

volcanic hot springs

a literal warm little pond that provides geothermal energy and a concentrating mechanism

Question 4

why do we think all life on earth comes from a common origin?

Answer 4

all life on earth is related by common ancestry (LUCA)

in the panspermia scenario, the common ancestor between earth and mars life would be an organism that travelled between worlds

pre or post dating LUCA

Question 5

what are some requirements for life to be transferred from one planet to another and why, even if this did occur, it limits our ability to explain the origin of life?

Answer 5

requirements:
- survive ejection from source planet (must be embedded in rock)
- space (must endure vacuum, radiation, extreme temps)
- transport time (thousands-millions of years)
- survive entry and landing (rock doesn’t burn up or kill organism inside it)

limits our ability to explain origin of life as it now goes beyond our own planet, making it a much more difficult question to answer a we know less about what’s out there than our own planet