Darwin

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					       Charles Darwin

  “. . .a theory of
    descent with
modification through
variation and natural
     selection.”
 The Expansion of Science
• Descartes' “Mechanical world” made science
  possible (although Descartes himself was
  not an empiricist)
• Carl von Linné (Linnaeus) published
  Philosophia Botanica (1752)
• The Age of Reason promoted the idea of
  “Progress” in science--more can be
  discovered. The Industrial Revolution
  begins.
Scientific Research Posed Problems:
Question # 1
How do we account for
fossils of species that appear
to be extinct?
In the Great Chain of
Being, every species
had a vital role to play
in God’s vast
ecological network.
     God would not
make spare parts.                “Whoa! What is this?
Scientific Research Problems Question # 1
John Wesley,                       “Such is the
the religious                      economy of
reformer,                          nature, that no
pronounced,                        instance can be
in 1770,                           produced of her
“Death is
never                              having
permitted to                       permitted any
destroy [even]                     one race of
the most         Where are these   animals to
inconsiderable   species
species.”         hiding?
                                   become
                                   extinct.” Thomas
                                   Jefferson, 1785
Scientific Research Posed Problems
Question # 2

The fossils of some
extinct species, e.g.,
mammoths, giant
sloths, horse-like
creatures, seemed
to resemble
contemporary
species. Were they
related; if so how?
The Fossil Record—Apparent Links

                             Archaeopteryx and
                             bird details




            Homo Erectus


                   Homo
                   Sapiens
The Fossil Record—Is this a Link?
Scientific Research Posed Problems
Question # 3
How do we account for the geographic
distribution of animals in the world, e.g.,
marsupials and flightless birds in Australia,
finches and turtles in the Galapagos Asian and
African elephants?
Did that all occur at the end of the trip on the
biblical ark? How did the species spread in
such exact patterns? Why are more closely
related species usually found closer to each
other (e.g., hummingbirds in the Galapagos,
drosophila in the Hawaiian islands).
Scientific Research Posed Problems
Question # 4
 Why does there appear to be a
 progression of complexity of fossils
 found in different layers of the earth’s
 crust?
 Why are there no species or only simple
 species in the oldest layers, and why do
 vertebrates appear only in more recent
 layers? Why are species in closer layers
 more closely related?
Scientific Research Posed Problems
Question #5

 How do we account for
the many evidences that
the earth is many
millions of years old?
Scientific Research Posed Problems
Question # 6
How do we reconcile the evidence that
people have been living and dying for
thousands of years with the Bible
record?
How do we reconcile evidence that
animals have been living and dying
steadily for millions of years with the
biblical idea that death did not occur
until after Adam’s fall.
How do we reconcile
these strange new
observations with
biblical creation,the
story of the fall, and
the story of the flood?
 Early Answers
De Maillet—1748      Aquatic animals evolved
                     land counterparts
De Maupertuis—1745   Species are not fixed.
                     Acquired traits or sports
                     may be passed on
Buffon—1749,1766     Families were fixed, but
                     variation of species in
                     families could vary
Lamarck—1802,1809    Species evolved by
                     passing on acquired
                     characteristics
Erasmus Darwin—1731- Supported evolutionary
1803                 ideas similar to Lamarck
 Ralph Waldo Emerson on Evolution
        [Ralph Waldo] Emerson's fledgling evolutionary
faith began to emerge in his 1834 lecture "The Relation of
Man to the Globe.“ [after reading Sir Charles Lyell’s
Principles of Geology] . . . "Man," Emerson said, "is no
upstart in the creation, but has been prophesied in nature
for a thousand thousand ages before he appeared." . . .
“[F]rom times incalculably remote" there had been a
"progressive preparation" for the human species, carried
out in the lower or "meaner creatures" preceding it.
"Man," as Emerson told his audience, "was not made
sooner, because his house was not ready."4
Emerson (Cont’d)
In this same lecture, Emerson chronicled the way in which
the hard rock that once surfaced the earth gradually
became covered with soils more hospitable to life. With
this development the "first faint traces of vegetable and
animal life begin to appear, and in the lowest strata the
most imperfect forms; – zoophytes, shells, and crustaceous
animals; then fishes and reptiles."5 When these
rudimentary forms had existed for some time, "Then a new
formation – the remains of a new and higher order – begin
to appear, more nearly resembling man, and giving earnest
of his approach; and as the new race waxes, the old race
retires."6
Emerson (Cont’d)
 As a result of his scientific studies, Emerson
concluded that one of the distinguishing
characteristics of the "present age" was "the
study of organic remains," and that "solid
learning is got from the fossils." When we
look at the geologic record, he reflected, there
are "No leaps, no magic," but rather the
"eternal tranquil procession of old familiar
laws.[1834]” (Gordon, Robert C., PhD)
Cuvier’s Proposal

The world has gone through a
number of great catastrophes,
with the flood being the last. After
each catastrophe, God would
repopulate the earth with a new
creation and a batch of new
species.
           A New Proposal
Charles Darwin, in 1859, proposed a
“theory of descent with modification
through variation and natural
selection.”
Charles Darwin--Background

It was intended that Charles, like his father
and grandfather, would become a doctor.
At Edinburgh, he could not bear to watch
the surgeries, done without anesthesia, so
he dropped out.
Later, he finished his studies at
Cambridge, where he studied for the
ministry. However, at Cambridge he
developed a passion for collecting
biological specimens.
  Charles Darwin--The Journey
His mentor at Cambridge, Henslow,
recommended him to be ship’s naturalist on
the HMS Beagle.
Darwin embarked on Dec. 27, 1831, for what
became a 5-year trip mapping the coastlines
around South America and elsewhere.
He took with him volume 1 of Sir Charles
Lyell’s new book, Principles of Geology. This
book argued that the world was millions of
years old, with changes taking place slowly.
Charles Darwin--After the Journey

 Darwin’s journals and specimens had
 assured him a good reputation
 before he had returned.
 He “wrote the book” on the
 formation of coral reefs.
 He did ground-breaking research on
 barnacles.
   Charles Darwin--The Theory
Darwin, in 1838, read Robert Malthus’s Essay on
Population, an essay that argued that animals would
have to struggle to survive since they would multiply
faster than the food supply.
For the first time, Darwin thought of a mechanism to
explain how extinct species could be related to
current species and how species could vary.
Nature was not unlike a breeder of horses; creatures
with mutations that helped them get a meal (or
escape being a meal) and a date were selected over
others.
 Natural Selection at work




<Bird of Paradise>
Charles Darwin--The Theory
In 1842, he wrote out a 35 page pencil sketch
of his ideas.
In 1844, he expanded it to 231 pages,
put the manuscript in a safe with some
money and instructions to publish it after
he was dead.
He wrote to Lyle, Hooker, Huxley and others,
explaining his theory. He continued research
on the theory of natural selection.
 Charles Darwin--The Theory
In 1845, he wrote, “In my wildest
daydream, I never expect more than
to show that there are two sides to
the question of the immutability of
species.” (Irvine)
During the next few years, he corresponded
with Alfred Russell Wallace, a naturalist in
Indonesia whose observations were leading him
in the direction Darwin had gone. But Wallace’s
ideas were tentative and undeveloped.
   Darwin--The Impetus to Publish
The bombshell came on
June 18, 1858. Alfred
Russel Wallace sent
Darwin a long letter
outlining his new theory
of species emerging,
reaching the same
conclusions in an
uncanny parallel to the
way that Darwin had.
 Charles Darwin--The Theory
In 1859, Darwin published On The Origin of
Species.
  Darwin’s Three Premises

• Creatures produce more offspring
  than can survive.
• There is great variation within a
  species.
• Some of that variation is passed
  on to future generations.
Darwin’s Conclusion--# 1
Natural Selection
 In a natural setting, through
natural selection, any variation (i.
e. mutation) that helps an
organism adapt to the
environment, i.e., get food,
escape predators, and find a
mate, is most likely to be passed
on.
Darwin’s Conclusion--# 2
Varieties could become new Species

Given the geologic age of the earth
outlined by Lyle, the variation occurring
within a species could become so great
that varieties would become new
species.
Given enough time, all species could
have evolved from one prototype.
     Evolution -- Fact or Theory?
• Since “descent with modification,” Darwin’s
  idea of evolution, is a fact, what is the big
  controversy over Darwin’s theory?
• Dogs, which come from one common ancestor,
  have evolved into great varieties.
• Cows give more milk, pigs have less fat,
  tomatoes are larger, sheep have more wool,
  turkeys have more white meat--many things
  have evolved.
Darwin’s Controversy # 1
Natural Selection
The controversy hinges on two main points.
First, while the variety among dogs, cows,
etc., is created by artificial selection,
Darwin argued that competition in
nature would cause the same kind
of variety by natural selection,
without divine direction.
Darwin’s Controversy # 2
New species could evolve from varieties
Second, given the great age of the earth
proposed by Sir Charles Lyle, variations
within a species could cross the
genetic line and become separate
species.
In fact, concludes Darwin, all species
might be developed from one original
prototype without divine intervention.
Darwin was impressed by “the extreme difficulty,
or rather impossibility, of conceiving the immense
and wonderful universe, including man . . . As the
result of blind chance or necessity. When thus
reflecting, I feel compelled to look to a First Cause
having an intelligent mind in some degree
analogous to that of man, and I deserve to be
called a Theist. . . . [But then] arises the doubt,
can the mind of man, which has, as I fully believe,
been developed from a mind as low as that
possessed by the lowest animal, be trusted when it
draws such grand conclusions.?” (Qtd. in Midgley, Mary.
“Purpose, Meaning and Darwinism.” Philosophy Now Jan./Feb.
2009: 16-19.)
  Summary
• Darwin did not introduce the idea of
  evolution; rather, he proposed the theory of
  Natural Selection.
• Darwin did not claim that humans came from
  monkeys; rather, he theorized that all species
  may have come from earlier prototypes,
  perhaps from one single prototype.
• His theory has profoundly affected the way
  we think about science and nature.
• For over a century, his basic claims have been
  largely supported by scientific studies.
Herbert Spencer
The Application of Evolutionary Thought
to Society in “Social Darwinism”
• Spencer was a prominent Victorian scientist
  whose aim was to bring fields such as
  psychology and sociology within the same
  framework and rigor as the natural and
  biological sciences.
• His social theories became known as “Social
  Darwinism” and were applied to capitalism,
  communism, and the nationalism that was
  the beginnings of the Nazi movement.
Herbert Spencer
The Application of Evolutionary Thought to Society

  Capitalism and “Social Darwinism”
     Capitalists such as Andrew Carnegie and John D.
   Rockefeller argued that capitalism was the best
   form of “survival of the fittest.”
     They argued that the government should not
   help the poor, infirm, or unfit. If the lower classes
   died in their factories of mills, that was just a
   natural process by which society was improved.
   Rockefeller called it “a Law of God and of Nature.”
Herbert Spencer
The Application of Evolutionary Thought to Society

• Communism and “Social Darwinism”
  Karl Marx saw in “Social Darwinism” the
  idea that we could alter the environment
  of individuals and thereby develop new
  traits and qualities. For example, the
  abolition of private property could lead to
  humans getting rid of their aggressions,
  leading to a Utopian society.
Herbert Spencer
The Application of Evolutionary Thought to Society

Nazism and “Social Darwinism”
  Early German nationalists
argued that nations were
essentially the same as members
of a species. When fighting
between nations occurred, the
human race was made “fitter.’
They also argued that it was a
natural process to eliminate
inferior nations or peoples.

				
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posted:11/22/2012
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