Transcript Evolution of Evolution

Evolution of Evolution
What is evolution?
What was going on this time period?
Who influenced the idea of evolution and how?
What is natural selection?
How did giraffes get such long necks?
Darwin’s Theory of Evolution
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Evolution – process by which modern organisms have
descended from ancient organisms…CHANGE
OVER TIME
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Scientific Theory – well-supported testable
explanation of phenomena that have occurred in the
natural world
Time Period – Most Europeans
Believed…

Earth was only a few thousand years old.
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The world was geometrical and regimented and will
never change.
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Rocks, mountains, etc were created by catastrophic
events that were rarely witnessed.
Influences
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Carl Linneaus
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If he could fine the pattern
in nature he could get
inside of God’s head.
Classified flowers into
groups based on
anatomical differences
Believed that the Earth
was complete – no gaps,
no failures
Buffon
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Was there a separate
creation for each variety?
Influences
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William Smith
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Believed that things had changed
since creation
Hypothesized that different animals
lived at different times
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Georges Cuvier
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Used comparative anatomy to
create replicas of extinct animals
in which only a few fossils were
found
Hypothesized that animals became
extinct due to catastrophes in
history…BUT what about
humans??
Influences
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William Buckland
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People were not wiped out by catastrophes
because they were not there.
A giant flood seemed to explain all of the
unexplainables. BUT why were many fish
killed off ?
George Stroke
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Volcanoes and old lava being cut through by
rivers was more evidence that Earth is older
than the Bible predicts.
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George Hutton
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Wind and water erosion take a very long
time, thus the Earth must be older than the
Bible predicts.
Lamarck’s Evolution Hypothesis
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One of the first to
realize that living things
changed over time
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Hypothesis –
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By selective use or disuse of
organs, organisms acquired or
lost certain traits during their
lifetime. These traits (acquired
or not) could be passed down
to their offspring. Over time,
this process led to a change in
species.
Lamarck’s Evolution Hypothesis
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Tendency Toward Perfection
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Use and Disuse
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All organisms have an innate tendency toward complexity
and perfection. Organisms will continually change and
acquire features that bring them closer to this goal.
Organisms could alter the size or shape of particular organs
by using their bodies in new ways.
Inheritance of Acquired Traits
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Acquired characteristics could be inherited.
Lamarck’s Evolution Hypothesis –
Incorrect in Several Ways
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Did not know how
traits were
inherited
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Did not know that
an organism’s
behavior had no
effect on its
heritable
characteristics
Influences
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Charles Lyell
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Hypothesized that geological
processes were the same as
they were in past as they are
now
The rate at which things
changed was very slow. Thus,
in order for all of these slow
processes to have taken place,
the Earth must be older than a
few thousand years.
“Principles of Geology”
Very influential to Charles
Darwin
Influences
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Thomas Malthus
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The population had the potential to grow at
a rate faster than food could be supplied. If
the population kept growing at this rate,
overpopulation was imminent unless
reproduction and/or survival was stopped.
Struggle for Existence
Charles Darwin
Travels – Voyage of the Beagle
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Charles Darwin sailed around the world via the H.M.S. Beagle from 1831-1836
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Collected plant and animal species
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Read latest scientific books (i.e. Lyell’s Principles of Geology)
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Recorded his observations and thoughts throughout journey
Galapagos Islands
Observations
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Many plants and animals seemed remarkably well-adapted to their
environments.
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Puzzled by where different species lived and did not live
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If Earth could change over time, couldn’t life itself change over time?
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Drew connections between Malthus’ work and his observations of plants and
animals
Malthus’ argument was stronger for plants and animals than for
humans.
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An overwhelming number of offspring die, while only a few surviving offspring
succeed in reproduction.
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http://www.pbs.org/wgbh/evolution/library/02/5/l_025_01.html
Charles Darwin –
Artificial Selection
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Artificial Selection – nature
provided the variation, and
humans selected those
variations that they found
useful
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Examples – farmer breeds his
best livestock
Darwin artificially selected
pigeons to show an analogous
example of how his
mechanism for evolution could
have worked.
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Reasoned that nature, given more
than a million years, could surely
achieve what he had artificially
achieved in a short amount of
time.
Influences
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Alfred Russell Wallace
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Collected beetles along the
Malaysian coast and noticed
variations in the beetles that
corresponded with the habitat in
which they were found
Made some conclusions and wrote
a letter to Charles Darwin
Conclusions – On the Origin of
Species
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Proposed natural selection
(mechanism for evolution)
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Presented evidence that evolution
has been taking place for millions
of years
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Driven to publish his theory came
from the fact that Wallace had
come up with the same idea.
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Even though he was afraid of the
Church’s reaction to his ideas he
wanted to get credit for his work.
http://www.pbs.org/wgbh/evolution/librar
y/11/2/e_s_2.html
Darwin v. Lamarck – How did
giraffes get such long necks?