Download "Nothing in Biology Makes Sense Except in the Light of Evolution

"Nothing in Biology Makes Sense Except in the Light of Evolution”
Theodosius Dobzhansky
Tree of Life
Masters of Metabolism
Estimated 105-107 procaryote species
1µm
Vorlesung Biophysik Braun - Evolution
RNA World ?
ATP,GTP
CTP,UTP
PNA
??
?
?
Protein
RNA
DNA
RNA
Protein
?
FeS, Pyrite
Metabolism
???
Vorlesung Biophysik Braun - Evolution
Replication
DNA
Diffusion Barrier
RNA
Protein
Ribozyme
Vorlesung Biophysik Braun - Evolution
Replication
DNA
Diffusion Barrier
RNA
Protein
Replication
Ribozyme
RNA
World
?
C UA
ATP
G
GTP CTP
A
A
UTP
U
U UC G
UG
U
C
U G
G
A A CU A A C
GC
G
C C
U
G UU C
G
AA
GU C
Self-Replication
Vorlesung Biophysik Braun - Evolution
The Origin of Life ?
Vorlesung Biophysik Braun - Evolution
Hydrothermal Vents
100m
2m
Vorlesung Biophysik Braun - Evolution
Locations: Hydrothermal Vents
Advantages of a hydrothermal vents
scenario of the origin of life:
- Methane is present at high concentrations: useful to form HCN as first
important metabolite.
- Discovery of Archaea as bacteria-like
creatures which can survive at high
temperatures (110°C) and within
rock. They are at oldest part of the
tree of life.
- Earth was initially under heavy meteorite bombardment - a deep-sea origin of life would have had stable
conditions. Vents existed all the
time.
- Strong gradients of temperature, pH,
redox-potential, chemicals generate
a rich far-from-equilibrium system
to drive metabolisms and reproduction.
Disadvantage:
- Risk that chemicals become heatdegraded at 370°C. Yet even at this
temperatures, stabilization by
adsorption to surfaces is possible.
From:
van Dover: The ecology of deep-sea hydrothermal vents
Vorlesung Biophysik Braun - Evolution
“Lost City”: Off ridge hydrothermal vent
From:
An off-axis hydrothermal vent Field near the Mid-Atlantic Ridge at 30°N, NATURE:412:145-149 (2001)
Vorlesung Biophysik Braun - Evolution
Archaea
Prof. Stetter, Regensburg
Vorlesung Biophysik Braun - Evolution
“The unseen majority”
(Whitman, PNAS, 95:6578, 1998)
“There is plenty of room at the bottom”
Vorlesung Biophysik Braun - Evolution
Motivation: The Selfish Gene
Following works of George Williams and William Hamilton, Richard Dawkins used the term “selfish gene” to
subsume findings in biology and molecular biology
where one gene is found to fight against other genes.
Instead of seeing organisms compete, Dawkins inverts
the viewpoint: the organism is only a vehicle of the
genes to replicate themselves. "A chicken is just an
egg's way of making more eggs."
The first edition of the book had not included cooperation findings of game theory and was criticized based
on its simple understanding of “selfish”.
At first glance, such an approach might be instrumentalized politically as it sounds egoistic, neo-liberal and
could be misunderstood as an attack on culturally rich
society from evolutionary biology.
I will hope, review of core ideas of game theory will
show that this is only a lack of our scientific fantasy.
We will later see how memory is crucial to explore the
efficient and more complicated social schemes by
explaining frequency-dependent selection and stable
evolution traps.
Vorlesung Biophysik Braun - Evolution
Matrix Games
Player B
Payoff
Matrix
Player A
e
-1
1
1
e
-1
-1
1
e
Let’s look at Knobeln (engl: to toss). Each
player can show (S)cissors, (P)aper or
s(T)one. Each of the player has profit
matrix depending on what the other is
playing. Typical for Knobeln is the payoff
matrix to the left, typically with e=0.
Note that the matrix has to be read in a left
to right fashion: Player A wins “1” if it has
stone against the scissor.
e –1 1
V = 1 e –1
–1 1 e
e.g. Partner Game:
V ij = V ji
Partner games are games where the payoff
is split between the playing partners, i.e.
the matrix is symmetrical
Vorlesung Biophysik Braun - Evolution
System Biophysics: Evolution
Evolution: Molecular Evolution of Life
o
o
o
o
o
o
o
o
o
o
o
o
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o
o
Timeline: some cosmological and geological background
Tree of Life: Clues, characteristics and starting organisms
Historical of ideas on the origin of life
Early experiments on biosynthesis
The big debate: Metabolism versus Replication
Self-Replication in Experiment and Theory
The stage: possible starting points on earth
Hydrothermal vents and convective approaches
Evolution Techniques: in vitro-evolution
The procaryotic-eucaryotic transition
The oxygen-catastrophy
The great extinctions
Darwin: the origin of species
Evolutionary strategies and examples
Models of population dynamics
Vorlesung Biophysik Braun - Evolution