Download darwin`s evidence i

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
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answers that you got and multiplying it times the 50 possible points.
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During the semester a student will occasionally forget his/her clicker or not come to class or
the battery will die or some problem will develop. To compensate for such problems, I will
add 10% additional pts to your score at the end of the semester.
Clicker Question
Which is an example of inductive reasoning?
A) Planets have an elliptical orbit; they are round
in shape and are large. Pluto has these
characteristics and so it is a planet.
B) I dissected two squid and noticed there were
3 chambers in the heart. I think that it is likely
that all squid have 3 chambered heats.
C) Hybrid cars get more miles/gallon than
conventional cars. I just bought a Prius hybrid. I
expect to get great gas mileage.

Which is an example of deductive
reasoning?
A)
B)
C)
The population of the USA is over 300 million.
I measured the body temperature of hundreds
of Mexican free-tailed bats and concluded that
they do not hibernate.
Webster’s dictionary says that birds are warm
blooded, have feathers and wings.
Archaeopteryx is a fossil vertebrate and has
wings & feathers. Based on the definition, I
would guess that it probably was warm
blooded.
And now the lecture.
DARWIN’S EVIDENCE I
QUESTIONS
 HOW DO WE ACCOUNT FOR THE
ORIGIN?
 DIVERSITY?
 ADAPTATION
 SCALA NATURAE?

of organisms
HYPOTHESES:
DEVINE CREATION
EVOLUTION
1.Sudden creation from nothing
1. No information on the Origin
2. Young Earth (~ 6,000 years)
2. Old Earth (millions of years)
3. Fixity of species
3. Species change over time
4. Separate ancestry for
humans & apes
4. Common ancestry for
humans & apes
5. The “Deluge” explains the
presence & distribution of
fossils
5. The “Deluge” doesn’t explain the
presence & distribution of
fossils
Shift towards evolution….because
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Religious dogmatism began to weaken

Protestant Reformation occurred
Catholic Church
Shift towards evolution….because

Religious dogmatism began to weaken

Shift from religious to secular reasoning
Science began to explain things that used to be
inexplicable
SCIENTIFIC ADVANCES

Telescope: Earth is NOT the center of the
Universe

Microscope: Microbes exist & cause
disease
SCIENTFIC ADVANCES
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Fossils
Show change over time
 Show extinction


Voyages of Discovery
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Many species found that were not mentioned
in the Bible e.g. kangaroos, giant moa birds
SCIENTFIC ADVANCES

Geology


Evidence of an old Earth
Lamarck & Darwin came up with
evolutionary mechanisms that could be
tested.
DARWIN’S HYPOTHESIS
Individuals vary
 Populations tend to over-breed
 Struggle for existence
 Survival of the fittest
 Variations are inherited
 New species develop

Deduction (Prediction) 1:
If the hypothesis of evolution is correct
then variations should exist among organisms
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Test: look at domestic animals
How does the variation occur?


Humans do it by
selecting which
animals breed
together—Artificial
selection.
Arguing by analogy
nature could produce
variation the same
way—Natural
selection.
Deduction (Prediction) 1:
If the hypothesis of evolution is correct
then variations should exist among organisms

Test: look at wild populations
Deduction (Prediction) 1:
Data:
Evaluation: Data support the hypothesis—
Variation exists among organisms
Deduction (Prediction) 2

If the hypothesis of evolution is correct
then more offspring are born than will
survive to reproduce
Test: Compare number born & their survival
Deduction (Prediction) 2
Data: Many are born
but few survive
SPORES
Evaluation:
Data support the hypothesis
Deduction (Prediction) 3

If the hypothesis of evolution is correct
then differences should exist among
offspring that survive & breed
& those that don’t.
Test: Look for differences
Deduction (Prediction) 3
Data: Difficult to obtain—natural selection is slow
Evaluation: Natural selection is probable (Darwin)
Natural selection in certain (Today)
Data support the hypothesis
Clicker Question

A)
B)
C)
D)
E)
What was the most compelling argument
Darwin offered for Natural Selection being the
causative agent for evolution?
He argued mutation could not do it alone
He used the analogy of artificial selection
He used the fossil record as evidence
He used pesticide resistance in insects as
evidence of natural selection
He argued that Thomas Malthus said that
over- population could cause evolution
Clicker Question

A)
B)
C)
D)
E)
What was the most compelling argument
Darwin offered for Natural Selection being the
causative agent for evolution?
He argued mutation could not do it alone
He used the analogy of artificial selection
He used the fossil record as evidence
He used pesticide resistance in insects as
evidence of natural selection
He argued that Thomas Malthus said that
over- population could cause evolution
Deduction (Prediction) 4

If the hypothesis of evolution is correct
then variations important to survival must be
inherited.
Test: No good test available (Darwin’s time)
Inheritance not understood, but
Look at artificial selection in the farmyard.
Are traits passed on?
Yup!
Deduction (Prediction) 4
Evaluation: Traits are usually passed on.
Data are inconclusive
Data support the hypothesis…….But……..
But……There is the Fleeming Jenkin’s argument
Good traits will be swamped
out by breeding
Deduction (Prediction) 5

If the hypothesis of evolution is correct
then the Earth must be old so that evolution had
time to occur.
Test: Look at the geological record
Deduction (Prediction) 5
Data: Depth
of the canyons
suggests age
Deduction (Prediction) 5
Data: Thickness
of the
rock strata
suggests age
Deduction (Prediction) 5

If the hypothesis of evolution is correct
then the Earth must be old so that evolution had
time to occur.
Evaluation: Earth’s age is unknown (Darwin)
Appears to be old
Data support hypothesis but………
BUT ……..
THERE IS SO MUCH MORE TO LEARN:
As Huxley said:
“It matters not what you would prefer
but what is true.”
It is a question of evidence!
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