Early Earth's atmosphere consisted of water vapour, nitrogen, methane, carbon dioxide, ammonia, hydrogen and hydrogen sulphide.
That the early Earth had a reducing environment, and that organic molecules could have formed spontaneously in such an environment.
Created conditions similar that that of early Earth, to test the Oparin-Haldane hypothesis, and amino acids + hydrocarbons found in organisms today were formed.
Earth was seeded with life form another planet, and that life didn't originate here.
Life Requirements (simplified)
Accurate replication and metabolism. Both are necessary for each other. IE DNA makes proteins to do stuff + replicate DNA, which creates proteins to do stuff + replicate DNA. Chicken or egg scenario.
Aggregates of abiotically produced molecules surrounded by a membrane or membrane-like structure. Hypothetical intermediate between the building-block molecules of life and prokaryote cells.
RNA capable of catalysing.
dating based on the half-life of a radioactive isotope. Half-life is independent of everything else.
The magnetic alignment in a rock core sample, and how it changes, allows scientists to date that way because the magnetic poles of the earth have reversed many times in the past.
rocklike structures composed of many layers of bacteria and sediment. Existed some 3.5 billion years ago, and still exist today.
photosynthetic prokaryotes, caused the first major increase in oxygen levels.
Steps of eukaryotic evolution through serial endosymbiosis
Prokaryotic cell's membrane folds inwards to increase surface area, nucleus develops + Endoplasmic reticulum from the infolding. Mitochondria (aerobic heterotrophic prokaryote) is engulfed. Then, if it is a plant, Plastid (photosynthetic prokaryote) is engulfed too.
Process of gaining organelles through engulfing. "You are what you eat"
series of endosymbiotic events. IE something engulfs something else and it helps both parties. (endocytosis)
First multicellular organisms, just collections of autonomously replicating cells. Some cells in these became specialised to help the group as a whole, and as such multicellular organisms began to develop.
Explosion in number of animal phyla.
Original supercontinent, through continental drift the continents diverged from each other.