History of Life Flashcards
When did the Earth form?
4.5 bya
When were the oldest rocks formed? (range)
3.8-4.0 bya
When were the oldest cells formed?
3.5 bya
Describe the Panspermia hypothesis for life.
Life & its building blocks came to Earth from outer space via asteroid
Describe the RNA World hypothesis for life.
genetic material (RNA) emerged first,
proteins later and both could function as catalysts to drive
development of cellular life
Describe the Metabolism First hypothesis for life.
The spontaneous formation of simple molecules lead to more complex molecules. This can be seen in lab simulations.
What 3 key things is RNA capable of that supports the RNA World hypothesis?
Self replication, codes for information, and can catalyze reactions.
Is there any RNA based life?
no
What is an example of a natural catalyst that could have been used in the Metabolism First hypothesis?
Minerals and porous rocks
Name two pros of the Metabolism First hypothesis
Thermodynamically favorable and explains the unusual chirality problem (left handed AAs and right handed sugars)
Which hypothesis for life is more widely favored?
Metabolism First
Recently, in Greenland, it was discovered that the oldest fossils were actually around …?
3.7 bya
Oxygenic phosphorylation evolved first in what?
cyanobacteria
How long ago did oxygenic phosphorylation evolve?
2.5 bya
Oxygenic phosphorylation involved the coupling of what two things?
Reaction center I and II
Oxygenic phosphorylation is found in ALL what two groups?
cyanobacteria and photoautotrophic eukaryotes
Is photosynthesis a prokaryotic or eukaryotic process?
prokaryotic
How did oxygen change the atmosphere ?
Reducing —> oxidizing
Oxygen was liberated by?
photosynthesis
There is evidence of the oxygen revolution in what?
Rock strata older than 2.5 byo
Rocks older than 2.5 by have reduced forms of what two elements?
iron and sulfur
There were only (uni/multi)cellular organisms during the Precambrian era
uni
When were the first multicellular organisms?
580 mya
In Ga, when were the first multicellular organisms?
0.58 ga
