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Lecture 3

Biology 1001A Lecture Notes - Lecture 3: Cyanobacteria, Archaea, Glycolysis


Department
Biology
Course Code
BIOL 1001A
Professor
Tom Haffie
Lecture
3

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Preyas
Lecture 3 - The Origin of Life
Earth is 4.6 billion years old
Life developed early --> rst form of life 4 bya
ostromatolites (3.5bya)
cyanobacteria
Tree of life demonstrates that all living things originated from one point
oLUCA (Last universal common ancestor)
oknown because they share 5 main characteristics
Cells made of lipids
Genetic system based on DNA
DNA to RNA to Protein transfer of information
Common system of protein assembly
ATP
Glucose & Glycolysis
What came before LUCA ?
oMany branches to before LUCA on the tree of life, but LUCA survived in
order to give rise to the 3 main categories we know today : Bacteria,
Archaea, Eukaryotes
Prokaryotes do not exist --> there is no single group of organisms
Misconceptions:
oprokaryotes include bacteria and archaea but these two are not related
in any way
o"Pro" anteriority (earlier) than eukaryotes
oevolutionary change always moves from simple to complex
LUCA may have been a proto-eukaryote --> meaning it had a nuclear
envelope
obut through the process of reductive evolution, bacteria and archaea
lost the nuclear envelope
reductively evolved in order to save energy, and increase rate of
reproduction
Stages of prebiotic evolution
oWhat is needed? --> Abiootic synthesis, Heritable information, cells,
metabolism
oGeophysical stage --> composition of the earth and atmosphere
well understood
oChemical stage ---> how could the building blocks of life be
synthesised
well understood
oBiological stage ---> how did the building blocks organize into living
cells
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