Origin of life Flashcards
How old is the universe?
13.7BY
What does Jupiter support?
Asteroid belt
Where did the earth water come from?
Late heavy bombardment - rocks, minerals dissolved
Describe the environment of the Hadean Eon
Smoggy Toxic environment
Dust/Ash in atmosphere
Anaerobic
Surface mostly water
Violent – 30m+ tides
Acidic
Sea regularly boils/churns
Approximately how long ago did life originate on earth?
3.8BYA
What are the 6 theories for the origin of life?
Panspermia
Clay minerals
Volcanoes
Ice
Primordial soup
Deep sea vents
What is the Panspermia hypothesis?
Life exists throughout the universe and can be distributed via space dust, meteoroids, asteroids, comets, or even spacecraft
What discovery supports the Panspermia hypothesis?
Uracil and nicotinic acid discovered on a non-terrestrial asteroid
What is the mineral clay hypothesis?
Life may have originated from self-replicating molecular structures on mineral surfaces, particularly clays
Describe the primordial soup theory
Key elements reacted with a spark of life from a high energy source to form the basic compounds for life
Amino acids
Carbon-based
Nucleic acids
What experiments support the primordial soup theory?
Miller-Urey
What’s wrong with the primordial soup theory?
Unlikely to happen spontaneously
Cannot create enough complexity
Lightning as the energy source could create, but could also destroy
The compound locations were likely very dilute
What gradients do you need to drive reactions?
Proton gradients
What are black smokers? Describe them
Deep-sea hydrothermal vents found along mid-ocean ridges, where superheated, mineral-rich water is expelled from the Earth’s crust.
Acidic
High Pressure
Iron Pyrites (Fe-S)
Why might life have originated around hydrothermal vents?
They are rich in chemical energy, minerals, and biodiversity
What is the basis of energy production in black smokers?
H2S (Hydrogen sulfide) can react with O2 (oxygen) to release energy. However, these vents are oxygen-poor. So H2S might react with Fe to form an acidic environment with iron pyrites as catalysts.
How might life have originated in alkaline hydrothermal vents?
The proton gradient between the alkaline vent fluid and the acidic ocean water could drive reactions essential for life, such as the synthesis of organic molecules and the fixation of carbon dioxide
What is LUCA?
Last universal common ancestor
A genetic and biochemical community of organisms, rather than a single being or species
