Download Evo Notes 1b

Selective
breeding
the raw genetic
material (variation) is
hidden there
Selective breeding
Hidden variation can
be exposed through
selection!
In historical context
 Other people’s ideas paved the path
for Darwin’s thinking
competition:
struggle for survival
population growth
exceeds food supply
land masses change over
immeasurable time
A Reluctant Revolutionary
• Returned to England in 1836
– wrote papers describing his collections &
observations
– long treatise on barnacles
– draft of his theory of
species formation in 1844
• instructed his wife to
publish this essay upon
his death
• reluctant to publish but
didn’t want ideas to die
with him
A LONG time coming
• Age 27: Returns from trip.
• Next 10 years: published books on islands,
reefs, and geography. Completed an 8 year
study of barnacles.
• 1842 Wrote manuscript and showed to friends
then placed in drawer for 16 years.
• Basically – he wrote and studied for the next
40 years.
D Observations
• Large Armadillo fossils resembled living
armadillos.
• Geographic change shows different features.
• Tourtoises have different shells depending on
Island.
• Plants similar to continent, not similar climate.
D Evidence
1. Fossils
a) Fossils of extinct organisms resemble living org.
b) Rock strata show fossil progression.
2. Geographic Distribution
a) Similar climates have different organisms
b) Island organisms most closely resemble nearest
continent.
3. Oceanic Islands
a) Endemic organisms on Islands resemble each other.
b) Island organisms resemble the nearest mainland.
D Previous Knowledge
• Thomas Malthus “Essay on Principle of Population”
1798.
• Potential for more offspring than can survive. Only a
limited number survive or they would take over the
world.
• Species with adaptations that aid in survival and
reproduction reproduce while harmful traits die out =
natural selection.
• Geometric Progression (increase by common factor) 2,
4, 16, 256.
• Arithmetic Progression (increase by constant
difference) 2, 4, 6, 8.
D Math
Malthus + Beagle + Experience with Breeding =
Survival of the Fittest
So What’s the Problem?
• Popular belief that Earth was only a few
thousand years old.
• Fear?
And then came the letter….
Then, in 1858, Darwin received a letter that
changed everything…
Alfred Russel Wallace
a young naturalist working in the East
Indies, had written a short paper with a
new idea. He asked Darwin to evaluate his
ideas and pass it along for publication.
The time was ripe for the idea!
To Lyell—
Your words
have come true
with a vengeance…
I never saw a more striking
coincidence…so all my originality,
whatever it may amount to,
will be smashed.
The time was ripe for the idea!
I’ll arrange for a joint
Presentation in London and
I’d better publish my manuscript
ASAP!
Voyage: 1831-1836
November 24, 1859, Darwin published
“On the Origin of Species by Means of Natural Selection”
Essence of Darwin’s ideas
• Natural selection
– variation exists in populations
– over-production of offspring
• more offspring than the environment can support
– competition
• for food, mates, nesting sites, escape predators
– differential survival
• successful traits = adaptations
– differential reproduction
• adaptations become more
common in population
LaMarckian vs. Darwinian view
• LaMarck
– in reaching higher
vegetation giraffes
stretch their necks &
transmits the acquired longer
neck to offspring
• Darwin

– giraffes born with longer
necks survive better & leave
more offspring who inherit
their long necks
Objectives 9/12/11
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Turn in 58 flashcards in your box (with your name on it)
Discuss homework image.
Continue evolution notes.
Begin Timeline?
Evolution Activity if there is time.
DUE DATES (also listed on rossman.educatorpages.com)
• 9/12 (Mon) Handwritten Evolution Flashcards complete.
• 9/12 (Mon) First Picture in Visual Book Complete - write as much as you can
about the image - What does it tell you? What's important to know? What
is still unknown about it?
• 9/12 (Mon) Rewritten Free Response Question if you want to bring up the
points on the test.
• 9/14 (Wed) Flashcards 1-20 memorized for quiz.
• 9/15 (Thr) Flashcards 21-40 memorized for quiz.
• 9/16 (Fri) All AP Bio Evolution flashcards memorized for quiz.
Stick your neck out…
Ask Questions!
Life has changed over time
& in turn has changed the Earth
Living creatures have
changed Earth’s environment,
making other life possible
Add to timeline
Galapagos
Recent volcanic origin most of
animal species on the Galápagos
live nowhere else in world, but
they resemble species living on
South American mainland.
500 miles west of mainland
Essence of Darwin’s ideas
(1) Variation exists in natural populations
(2) Many more offspring are born each season than can possibly survive
to maturity
(3) As a result, there is a struggle for existence
- competition
(4) Characteristics beneficial in the struggle
for existence will tend to become more common in the population,
changing the average characteristics of the population
- adaptations
(5) Over long periods of time, and given a steady input of new variation into a population,
these processes lead to the emergence of new species