Evidence for Evolution
Chapters 22 & 24
Review Chapters 25 & 26 (from
September)
Larmarck…
Darwin: Natural Selection
How does evolution really work?
•
•
•
•
Overproduction of offpsring
Variation within a population
Struggle for existence
Differential survival and reproduction
PBS Evolution: How does evolution really work?
Case Studies:
(I am betting on this in the near AP
future…)
• Classic:
– Explain this in terms of Darwin’s finches
• Modern:
– News flash: “Overuse of antibiotics leading to
increased resistance”
• Explain how
– Darwin would explain this
– What would be considered “Lamarckian thinking”
Other Evolution videos
• How do we know evolution really happens?
• Did humans evolve?
• Why does evolution matter now?
Evidence
•
Artificial Selection
– Cabbage example
•
Role of fossil evidence
– Carbon Dating
– Law of superposition and relative dating
– Convergent and Divergent Evolution
•
•
Homologous and Analogous structures
Biogeography
– Island geography
– Adaptive radiation
•
Genetic evidence
– Protein similarities
– DNA similarities
•
Embryological Evidence & other Developmental Evidence
– Ontogeny recapitulates phylogeny…is this evidence valid alone?
– Heterochrony & Paedomorpheosis
Artificial Selection: What Darwin
based his ideas on
• What is the ultimate source of variation?
• What might cause these differences?
Carbon dating
• Is carbon dating
useful for
understanding
the
relationships
between all
modern
organisms and
their ancestors?
Law of superposition and relative
dating
• How does relative
dating deal with
the limits to carbon
dating?
Convergent evolution
• Distinct ancestral
history
• Similar selective
pressure
• “Analagous
structures”
• What other
analagous structures
can you think of?
Divergent Evolution
• Shared ancestral
history.
• Different selective
pressure.
• “Homologous
structures”
• What other
homologous
structures can you
think of?
Adaptive Radiation
• Archipelagos; around mountain ranges.
• Different selective pressures, different traits:
eventually different species
Molecular Evidence
• When might looking at amino acid sequences be more
useful than comparing DNA sequences?
Embryological evidence
• “Ontogeny recapitulates
phylogeny”
• What does this mean?
Why is this evidence
highly contested? What
does this say about any
ONE piece of evidence
for evolution?
• How is can this be
stretched further to show
that sea starts and
vertebrates are actually
close relatives?
Heterochrony & Paedomorphosis
• Timing of
development causing
changes.
• Paedomorphoesis:
– Sexually mature
species that retains
juvenile conditions; ex.
Adult salamander with
gill slits.
Did Darwin get it all?
Darwin had questions…
• What is the selective pressure here?
“Missing Links”
• Mini-case study: Tiktaalik
– http://evolution.berkeley.edu/evolibrary/news/06050
1_tiktaalik
•
•
•
•
What is a transitional fossil?
What is a clade?
Why was it important to find this fossil?
What are the questions that still exist and does
this negate the importance of this find?
• What could be a mechanism for a large
evolutionary change in a short time period?
Perfection…not!!!
• Evolution is NOT GOAL oriented
– Selection can only act on existing variation.
• King Corn
– Evolution is limited by historical constraints.
• Vestigial structures (limb buds)
– Adaptations are often compromises.
• Is bigger better?!? (Salmon)
Be the college board!
• You are working for the college board and you
want to understand high school students’
knowledge of evolution and relate to current
events.
• Write a 3-part question that shows whether or
not students understand evolution by natural
selection and can relate to a current event.