Evidence for Evolution Chapters 22 & 24 Review Chapters 25 & 26 (from September)

Evidence for Evolution

Chapters 22 & 24Review Chapters 25 & 26 (from

September)

Larmarck…

Darwin: Natural SelectionHow 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/

060501_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.