Download The Major Transitions in Evolution

Our understanding of man’s place
in the universe
Eörs Szathmáry
Collegium Budapest
Eötvös University
“In between infinity and nothing”
• “For after all what is man in
nature? A nothing in relation to
infinity, all in relation to
nothing, a central point between
nothing and all and infinitely far
from understanding either. The
ends of things and their
beginnings are impregnably
concealed from him in an
impenetrable secret. He is
equally incapable of seeing the
nothingness out of which he
was drawn and the infinite in
which he is engulfed. “
Blaise Pascal (1623-1662)
Units of evolution
1. multiplication
2. heredity
3. variation
hereditary traits affecting
survival and/or
reproduction
The major transitions (1995)
*
*
*
*
* These transitions are regarded to be ‘difficult’
Difficulty of a transition
• Selection limited (special environment)
• Pre-emption: first come  selective
overkill
• Variation-limited: improbable series of rare
variations (genetic code, eukaryotic
nucleocytoplasm, etc.)
Difficult transitions are ‘unique’
• Operational definition: all organisms
sharing the trait go back to a common
ancestor after the transition
• These unique transitions are usually
irreversible (no cell without a genetic code,
no bacterium derived from a eukaryote can
be found today)
Recurrent themes in transitions
• Independently reproducing units come
together and form higher-level units
• Division of labour/combination of function
• Origin of novel inheritance systems
Increase in complexity
• Contingent irreversibility
• Central control
Chemical evolution was a race
between tar formation and life
formation
Chemical networks
Life
Tar
What fraction of planets would end
up with just tar?
Gánti’s chemoton model (1974)
metabolism
template
copying
membrane
growth
ALL THREE SUBSYSTEMS ARE AUTOCATALYTIC
Pathways of supersystem evolution
metabolism
MB
boundary
MT
template
BT
MBT
INFRABIOLOGICAL SYSTEMS
Primate phylogeny
Chronology and geography
The coevolutionary star and the
human adaptive suite
The social brain
On human cooperation
• Bowles, S. (2006) Group competition,
reproductive levelling, and the evolution of
human altruism. Science
• A possible explanation—that groups with
more altruists survive when groups
compete—has long been judged untenable
on empirical grounds for most species.
On human cooperation II.
• Empirical estimates show that genetic differences
between early human groups are likely to have
been great enough so that lethal intergroup
competition could account for the evolution of
altruism.
• Crucial to this process were distinctive human
practices such as sharing food beyond the
immediate family, monogamy, and other forms of
reproductive levelling.
On human cooperation III.
• These culturally transmitted practices
presuppose advanced cognitive and
linguistic capacities, possibly accounting
for the distinctive forms of altruism found
in our species.
Why is language so interesting?
• Because everybody knows that only we talk
• …although other animals may understand a
number of words
• Language makes long-term cumulative
cultural evolution possible
• A novel type of inheritance system with
showing “unlimited hereditary” potential
Design features of language
• Compositionality (meaning dependent on how
parts are combined)
• Recursion (phrases within phrases)
• Symbolicism (versus icons and indices)
• Cultural transmission (rather than genetic)
• SYMBOLIC REFERENCE and SYNTAX
Three interwoven processes
• Note the different time-scales involved
• Cultural transmission: language transmits itself as
well as other things, and has its own dynamics
Understanding language
evolution is difficult
BUT: Recursive syntactic pattern
learning in birds!
• European starlings (Sturnus vulgaris) accurately
recognize recursive syntactic patterns
• They are able to exlude agrammatical forms
• Centre-embedding is not uniquely human?
Patterns are made up of naturally
occurring vocal patterns
• Learning to classify by operant conditioning
• This is NOT production!
Note on human understanding
unknown
time
known
Boundary to the unknown
known
known
time
Infinite, limited progress
knowledge
Speciesspecific limit
time