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Coyne – Chapter 5.
Hornets versus European honey bees –
https://www.youtube.com/watch?v=6fTrSOFyfxs
Hornets versus Japanese honey bees –
http://video.nationalgeographic.com/video/bees_vs_hornet?source=relatedvideo
Unparasitized Ant
Parasitized Ant
Parasitized ant Among
the Berries
Cryptic Katydids
Cryptic Katydid
Flower mimicking bee to attract males
What has to happen for evolution via natural selection to occur?
Why do we say that mutations are random?
In what sense are mutations not random?
Is evolution random?
Coyne puts up some pretty big demands on natural selection.
What are they?
MISCONCEPTION: Natural selection acts for the good of the species.
MISCONCEPTION: Natural selection involves organisms trying to adapt.
What is genetic drift?
How does drift compare to natural selection?
In what ways are artificial selection (i.e. domestication of dogs, breeding of
crops for particular traits) alike?
In what ways are they different?
What are the lessons to be had from humans selecting on dogs, corn, wheat, rice, cows, etc.?
Evolution, HIV, and AZT
Geospiza fortis and Daphne
Major – Darwin's Finches in the
Galapagos Islands
Beak depth is variable within populations.
Beak depth is heritable.
In 1977, there was a huge draught and lots of birds died due
to lack of food.
The abundance of seeds declined.
The few seeds that were left were large and hard.
If we compare
the original
birds with the
survivors, we
see that the
survivors had
deeper beaks.
The offspring of the
survivors had larger
beaks (like their
parents) compared to
finches hatched
before the draught.
draught
Another depiction
of how beak size,
beak shape, and
body size changed
with the draught.
draught
draught
Geospiza fortis and Daphne
Major – Darwin's Finches in the
Galapagos Islands
Soapberry Bugs
Soapberry bugs in Florida
Example of rapid evolution due to natural selection:
Soapberry bugs
Soapberry bugs
have long,
needlelike beaks,
the they use to
penetrate the
fruits of plants
and consume
seeds. They
liquefy the
contents and
then suck them
back up.
Native plantBugs have long
mouthpart
Introduced plantBugs have short mouthpart
Soapberry
Nativebugs
plantBugs have long
mouthpart
Introduced plantBugs have short
mouthpart
Soapberry bugs (Jadera haematoloma) and their native and introduced
host plants in Texas and Florida, drawn to scale
Native Host Plant
Introduced Host Plant
The Evolution of Complex Biochemical Pathways
Has there been enough time for evolution to have produced all of the biological
diversity that we see today?
MISCONCEPTION: Natural selection gives organisms what they need.
MISCONCEPTION: All traits of organisms are adaptations.