Transcript The Evolution of Behaviour

The Evolution of
Behaviour
Psychology 3106
Introduction
We have looked at causal mechanisms up
to this point
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Development
Genetics
Neurons
Behaviour has an evolutionary history as
well
Introduction
We can look at the origins of behaviour
and changes over time
We can look at fitness consequences
These two points are, obviously, related
Evolution of Behaviour
So, if we want to reconstruct evolution we can
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Look at the fossil record
Behaviour doesn’t fossilize all that well…..
Explore some interesting behaviour using the
comparative method
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Look at related species
If a behaviour is widespread it may have evolved in a
common ancestor of the species
If a behaviour only eixists in one or a few species it
may be relatively recent.
An Example
Empid fly courtship
ritual
Male presents a silk
gift to the female
In most related
species the female is
larger than the male
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The male ends up
being dinner…
Empid Flies, the saga continues…
In some species the males present food to
the females, distracts them
Still others adorn the gift with silk strands
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Makes it take longer to eat
More conspicuous too
Still others cover it with silk
Some eat the gift, and give the female the
wrapper
Finally, some just give the silk
The History of Flight
Archaeopteryx
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‘ancient bird’
Did it fly from tree to
tree?
Did it run and take
off?
Its wings and feathers
were modern
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The wings had claws!
Scary flying Dinobirds
Wings were powered by reduced muscle
mass
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Suggests Archie just soared
Used claws to grasp a tree at the end of a
glide
Perhaps it had reptilian muscle
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2x the peak power….
Walking on two feet in people!
Chimps are
quadropeds
We are Bipeds
Hmmm. What’s up
with that
You can look at the
pelvis of various
species of hominid
Standing up may
have been the key in
becoming who we are
Evolution of generalist strategies in
Cowbirds
Would make sense
that nest parasitism
started out as a
specialist strategy
More recent the
cowbird, the more of
a generalist it should
be
DNA studies show it
to be true
Conclusion
You can reconstruct the evolution of
behaviour (or any trait) using the
comparative method
You can never be entirely sure
Use of new techniques like molecular
methods can really help, even with
behaviour