Charles Darwin - PowerPoint PPT Presentation

Loading...

PPT – Charles Darwin PowerPoint presentation | free to view - id: 3fa25-MmFjN



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Charles Darwin

Description:

Charles Darwin ' ... Charles Darwin, in 1859, proposed a 'theory of descent with modification through ... Charles Darwin--The Theory. The bombshell came on ... – PowerPoint PPT presentation

Number of Views:305
Avg rating:3.0/5.0
Slides: 40
Provided by: edre
Category:
Tags: charles | darwin

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Charles Darwin


1
Charles Darwin
  • . . .a theory of descent with modification
    through variation and natural selection.

2
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.

3
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 Gods vast ecological
    network. God would not make spare parts.

4
Scientific Research Problems Question 1
Such is the economy of nature, that no instance
can be produced of her having permitted any one
race of animals to become extinct. Thomas
Jefferson, 1785
  • John Wesley, the religious reformer, pronounced,
    in 1770, Death is never permitted to destroy
    even the most inconsiderable species.

5
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?

6
The Fossil RecordApparent Links
7
The Fossil RecordIs this a Link?
8
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).

9
Scientific Research Posed Problems Question 4
  • Why does there appear to be a progression of
    complexity of fossils found in different layers
    of the earths 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?

10
Scientific Research Posed Problems Question 5
  • How do we account for the many evidences that
    the earth is many millions of years old?

11
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 Adams fall.

12
  • How do we reconcile these strange new
    observations with biblical creation,the story of
    the fall, and the story of the flood?

13
Early Answers
14
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 Lyells 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." . .
    .
  • From 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

15
Emerson (Contd)
  • 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

16
Emerson (Contd)
  • 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)

17
Cuviers 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.

18
A New Proposal
  • Charles Darwin, in 1859, proposed a theory of
    descent with modification through variation and
    natural selection.

19
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.

20
Charles Darwin--The Journey
  • His mentor at Cambridge, Henslow, recommended him
    to be ships 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 Lyells
    new book, Principles of Geology. This book argued
    that the world was millions of years old, with
    changes taking place slowly.

21
Charles Darwin--After the Journey
  • Darwins 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.

22
Charles Darwin--The Theory
  • Darwin, in 1838, read Robert Malthuss 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.

23
Natural Selection at work
ltBird of Paradisegt
24
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.

25
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 Wallaces ideas
    were tentative and undeveloped.

26
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.

27
Charles Darwin--The Theory
  • In 1859, Darwin published On The Origin of
    Species.

28
Darwins 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.

29
Darwins First Premise
  • Creatures produce more offspring than can
    survive.
  • From Robert Malthus, Darwin got the idea that
    the population of a species grows faster than the
    food supply therefore, there will be a
    competitive struggle for food. In the process of
    the struggle for food, those more fit will live.

30
Darwins Second Premise
  • There is great variation within a species.
  • From his travels on the Beagle, on which he
    collected thousands of specimens, as well as in
    his observations of pigeons, dogs, other
    domesticated animals, and the human species,
    Darwin observed a huge variety within a species.
    Even within this class, we all vary.

31
Darwins Third Premise
  • Some of that variation is passed on to future
    generations.
  • Although Darwin had not read Mendel, he knew, as
    we do, that some of the variation that randomly
    occurs within a species is passed on. For
    example, people born with an extra finger
    (polydactyly) often had descendants with extra
    digits. Sheep with thicker wool were bred
    (artificially selected) to produce offspring with
    thicker wool. Cows giving more milk are bred to
    produce offspring who also give more milk.

32
Darwins Conclusion-- 1Natural 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.

33
Darwins Conclusion-- 2Varieties 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.

34
Evolution -- Fact or Theory?
  • Since descent with modification, Darwins idea
    of evolution, is a fact, what is the big
    controversy over Darwins 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.

35
Darwins Controversy 1Natural 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.

36
Darwins Controversy 2New 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.

37
  • 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.)

38
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.

39
Herbert SpencerThe 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.

40
Herbert SpencerThe 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.

41
Herbert SpencerThe 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.

42
Herbert SpencerThe 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.
About PowerShow.com