Download Evolution…

Alfred R. Wallace
Charles Darwin
Evolution…day 1
Thomas
Huxley
Gregor Mendel
R.A. Fisher
Theo. Dobzhansky
Barbara McClintock
J.B.S.
Haldane
Stephen J. Gould
Schedule
• Feb 5:
• Feb 7:
• Feb. 12:
• Feb. 14:
• Feb. 19
• Feb. 21
Natural Selection & Evolution
Phylogenetics & Major Transitions
(assignment due Feb. 14:
Phylogeny Problem and Topic selection for paper)
Documentary OR day off with an evening viewing of
the documentary?? Schedule?
Origins of Life
Origins of Structure & Adaptation
Origins of Species
Great Ideas (Pyles!): Assignments
1. Problem in Phylogenetics
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Instructions Thursday Feb. 7
Can be completed individually or pairs (2 only per team)
DUE Feb. 14th (happy valentines’ day)
2. Paper on Evolution (individual)
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Instructions on Thursday Feb. 7
Topics (your topic selection due Feb. 14):
1.
2.
3.
4.
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Homo sapiens: X = evidence of bad design?
Evolution of the group X
Evolution of the characterisic X
Propose something (but no politics, please)
DUE March 11
When analyzing a scientific explanation, which of the
following is most important?
1.
2.
3.
4.
5.
Logic
Data
Source (i.e., scientific standing of the author
or institution)
Hypothesis
All of the above
FREE FLOW ….
The best definition of the process of EVOLUTION is:
1.
2.
3.
4.
5.
6.
7.
Survival of the fittest.
Origin of new species from existing species.
Different individuals leave behind different numbers of
offspring.
Selection of new traits in a species from environmental
pressures.
Humans descended from chimps in Africa.
The Strong eventually eliminate the Weak.
A steady march of progress from microbes to man.
Natural Selection


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Some characteristics of individuals are heritable
Some individuals will have higher survival rates
Some individuals will have higher reproduction
(more offspring = higher fecundity)
• If heritable characteristics are linked to those
individuals with higher fecundity…

THEN, the next generation will have “more” of those
advantageous heritable characteristics
Thus, differential reproduction of individuals with
heritable characteristics will shift the genetic “profile”
of the population, increasing those advantageous traits
in the next generation…and so on, and so on…
Modern Synthesis: Evolution
Differential reproduction (aka natural selection) can
shift the genetic profile of organisms over time.
Are there any other phenomena that can also affect
the genetic profile of a group of organisms over time?
YES!
Modern Synthesis: Evolution

Genetics:
 Mutations
 Chromosomal changes
 Duplication of a gene or genes
 Incomplete reproductive isolation (“hybrids”)

Population size or composition
 Immigration or loss of “portions” of original group
 Emigration from “outside” sources


Nonrandom mating
Historic Contingency
 Random events
(e.g., huge meteors! disease! Fast climate change!, etc.)
Modern Synthesis: Evolution
Natural Selection
Genetic mechanisms
Population size or composition
Nonrandom mating
Historic Contingency
Misconceptions
HOW IT WORKS!
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Evolution is progressive
Evolution is random
Organisms “try” to adapt
Natural selection gives organisms what they ”need”
Gaps in the fossil record disprove evolution
Evolution cannot be observed or tested
Scalae naturae
(Aristotle)
Survivors
Origins &
Extinctions
{
Darwin’s concept of “tree of life” (1859)
TETRAPODA
Which came first…??
Of the following pairs, which came first historically?
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FISH or AMPHIBIANS
MOSS or FISH
DINOSAURS or BIRDS
BEES or FLOWERS
EUKARYOTIC or PROKARYOTIC cells
CELLS or VIRUSES
Misconceptions
HOW IT WORKS!
•
•
•
•
•
•
Evolution is progressive
Evolution is random
Organisms “try” to adapt
Natural selection gives organisms what they ”need”
Gaps in the fossil record disprove evolution
Evolution cannot be observed or tested
Misconceptions
• Random?

Sometimes yes…
 Mutations and genetics “jumps” (e.g., gene duplication)
 Historic contingencies

Sometimes no…
 Natural selection is NOT random
 Nonrandom breeding is not…well, you know
Misconceptions
HOW IT WORKS!
•
•
•
•
•
•
Evolution is progressive
Evolution is random
Organisms “try” to adapt
Natural selection gives organisms what they ”need”
Gaps in the fossil record disprove evolution
Evolution cannot be observed or tested
Misconceptions
• Organisms can “think” ahead
NOPE!

Giraffes can’t get longer necks by “stretching”
 Giraffes with longer necks get more food and are able to
reproduce more offspring
They don’t “think” their way there…
• Nature can “think” ahead
NOPE! Nature can’t predict what will happen next
METEOR!!…RUN!
And, oh by the way…scientists can’t predict either!
Misconceptions
HOW IT WORKS!
•
•
•
•
•
•
Evolution is progressive
Evolution is random
Organisms “try” to adapt
Natural selection gives organisms what they ”need”
Gaps in the fossil record disprove evolution
Evolution cannot be observed or tested
Gaps?
A
A
Z
= one gap
B
Z
= 2 gaps
Z
= 3 gaps
Z
= 4 gaps
A
C
B
A
C
B
D
“Shanks paradox” named for the author…
At least a little logic is a requirement for any argument.
Misconceptions
HOW IT WORKS!
•
•
•
•
•
•
Evolution is progressive
Evolution is random
Organisms “try” to adapt
Natural selection gives organisms what they ”need”
Gaps in the fossil record disprove evolution
Evolution cannot be observed or tested
Misconceptions
• Science is not restricted to controlled experiments.
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Astronomers cannot hold stars in their hands,
Geologists cannot go back in time,
Epidemiologists don’t create epidemics to study them.
But in all cases scientists can learn a great deal by using
multiple lines of evidence to make valid and useful
inferences about their objects of study.