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What is the Evidence for Evolution?

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What gas could not have been present in the early atmosphere if organic ... Georges Cuvier (1812)- father of paleontology, suggested that God had created ... – PowerPoint PPT presentation

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Title: What is the Evidence for Evolution?


1
What is the Evidence for Evolution?
  • Chapter 15

2
Quiz 3
  • What gas could not have been present in the early
    atmosphere if organic compounds were synthesized
    naturally?
  • Name one of the three scientists who did
    experiments suggesting that spontaneous
    generation was false.
  • Were the first cells believed to be heterotrophs
    or autotrophs?

3
Quiz 3 Continued
  • Who wrote, The Origin of Species?
  • Who is the father of modern taxonomy?

4
Overview
  • Introduction to Evolutionary Theory
  • Brief History of Western Ideas on Evolution
  • Various Evidences for Evolution
  • The Mechanism of Evolution

5
Defining Evolution
  • Darwin- descent with modification
  • heritable change in populations over time
  • adaptive change- a genetic change that increases
    an organisms chances of perpetuating its genes
    in future generations
  • Microevolution- changes in the frequences of
    alleles of genes in a population
  • Macroevolution- the process by which species and
    higher groupings or organisms originate, change,
    and go extinct

6
How does heritable change come about?
7
Darwinian Evolution
  • the mechanism- natural selection
  • the rate of evolution-gradual and steady

8
What is the debate about?
  • In sharp contrast, modern biologists consider
    evolution- the principle that the heritable
    traits of organisms change over time-itself an
    incontestable fact
  • Can the small, random genetic changes observed
    today explain all of the various life-forms alive
    on the planet today?

9
Brief History of Western Ideas on Origins
10
Carolus Linnaeus (1707-1778)
  • The father of modern taxonomy
  • Kingdom, Phylum, Class, Order, Family, Genus,
    Species
  • God creates, Linnaeus arranges
  • Relatedness does not imply evolution in his mind
  • Why do organisms fall so naturally into families?

11
The Age of the Earth and Catastrophism
  • James Hutton (1788)-Through geological studies
    suggested that the earth was far older than 6,000
    years
  • Georges Cuvier (1812)- father of paleontology,
    suggested that God had created multiple times
    throughout the history of the earth
  • Charles Lyell (1830) published Principles of
    Geology- Uniformitarianism

12
Jean Baptiste Lamarck (1809)
  • Proposed Evolution
  • Mechanism was an inherent drive toward
    perfection and increased complexity, and from the
    felt needs of the organism

13
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14
Charles Darwin
  • Studied for the Ministry at Cambridge in 1828 at
    age 19
  • Ship naturalist on board the H.M.S. Beagle for 5
    years
  • Published On the Origin of Species by Means of
    Natural Selection in 1859

15
Various Evidences for Evolution?
  • The Fossil Record
  • Biogeography
  • Comparative Anatomy
  • Comparative Molecular Biology

16
Interpreting Data as Evidence for Evolution
  • Children look more like their parents than other
    people because they are descended from their
    parents and are genetically related. By analogy,
    organisms that look similar to one another are
    likely to be descended from a common ancestor

17
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18
Precambrian Era
  • Origin of Earth until about 550 million years ago
  • 3.5 billion years ago, prokaryotic-like fossils
  • Multicellular organisms appear about 800 million
    years ago, including jellyfishes, corals, and
    worms, and unfamiliar organisms

19
Paleozoic Era
  • 550 million to 245 million years ago
  • Organisms representing all 6 kingdoms present by
    the end of the era
  • estimated 90 of species went extinct at end,
    perhaps due to the climate becoming much more dry

20
Mesozoic Era
  • 250-65 million years ago
  • includes the age of reptiles land plants and
    animals diversify
  • estimated 75 of species extinct

21
Cenozoic Era
  • 65 million years ago to present
  • diversification of mammals, birds, insects, and
    flowering plants

22
What does the fossil record mean?
  • Organisms are distributed relatively consistently
    in rocks of the same age
  • Some organisms that are intermediate forms
    between major classes are present
  • Recent fossils generally look more like things we
    see today

23
Biogeography
  • Study of the past and present distributions of
    plant and animal species
  • Reveals that endemic species are most closely
    related to nearby species, even if they live in a
    considerably different environment

24
Comparative Anatomy
  • homologous structures are ones that are
    physically similar
  • they may have similar or very different functions

25
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26
  • analogous structures- structures with similar
    functions that do not appear structurally related

27
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28
Vestigial Structures?
29
Comparative Molecular Biology
  • All cells use DNA as genetic information, RNA,
    ribosomes, and use approximately the same genetic
    code
  • Comparisons of protein sequences used to
    establish relatedness
  • Cytochrome C, 35 of 104 amino acids are the same
    in all organisms
  • DNA/DNA hybridization

30
The Mechanism of Evolution
  • Why is mechanism important?
  • Can random mutation and natural selection ,
    acting gradually over time, create new genera,
    families, and all the higher taxa?

31
Darwins Natural Selection
  • All species produce more offspring than will
    themselves survive to produce offspring (Struggle
    for Existence)
  • Variation exists and much of the variation is
    heritable
  • Adaptive traits are passed on differentially and
    may accumulate within a population

32
Artificial Selection
  • Can produce huge phenotypic variation
  • Does not generate new species
  • What is a species?

33
Rate of Evolution
  • Depends on selective pressure
  • Depends on the extent of variation
  • What if selection is strong but no individual in
    population has trait to give it an advantage
    under such conditions?
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