Lecture 2: Out of the primordial soup... Flashcards
When was the Archean?
From 4 Ga to 2.5 Ga
What are Archean shields/ cartoons?
The first continental crust.
What happened ~4 Ga?
Late heavy meteorite.
Steam began to condense = oceans (freshwater)
Water lain sediments ~3.0 Ga
Erosion = salty erosion
What was Miller/Urey Primordial soup in the 1950s
Tried to replicate conditions of Earth from its start, replicated atmosphere, sun and lightning; found amino acids in mixture after several days, proved “primordial soup” hypothesis
What was Panspermia?
Sir Fred Hoyle & Chandra Wickramasinghe- ‘life’ was seeded onto the Earth from space.
How did the first kind of organisms, anaerobic heterotrophic cells, derive their nutrients/ energy?
From organic materials present in environment in absence of O2.
As heterotrophic cells increase…
Resources decreases…
Competition for energy meant cells that could produce own energy has competitive advantage.
What can stable carbon isotopes preserved in rocks be used for?
Ratios indicate biological fractionation by photosynthesis.
What are prokaryotic cells?
Pro = before
Karyote = nucleus
Simple- no membrane bound organelles or nucleus.
What are hydrothermal vents?
Black smoker chimneys
>350 degrees
Energy: heat, reduced compounds (e.g H2S)
Simple organics
Provide all necessary trace elements for metabolic mechanisms
Clay minerals
What are the necessary trace elements for metabolic mechanisms?
Na Mg Ca K Mn Zn Cu Co
How do prokaryotic cells reproduce?
Reproduction by binary fission
Where are prokaryotic cells found?
Found around hydro thermal vents.
Describe the process by which the Earth’s oceans became saline.
water-lain sediments ~3.9 Ga
erosion = salty oceans
All wrapped up: the cell membrane
lipid-like molecules (amphiphiles) form bilayered vesicles cyclic wetting/drying tide pools trap RNA in ‘cell’ membranes
