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OBJECTIVES

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Compare and contrast Aristotle's scala naturae to Carolus Linnaeus' ... Explain the mechanism for evolutionary change proposed by Jean-Baptiste de Lamarck. ... – PowerPoint PPT presentation

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Title: OBJECTIVES


1
OBJECTIVES     
  • The Historical Context for Evolutionary Theory
  • Explain the mechanism for evolutionary change
    proposed by Charles Darwin in On the Origin of
    Species.
  • Define evolution and adaptation.
  • Compare and contrast Aristotles scala naturae to
    Carolus Linnaeus classification scheme.
  • Describe the theories of catastrophism,
    gradualism, and uniformitarianism
  • Explain the mechanism for evolutionary change
    proposed by Jean-Baptiste de Lamarck. Explain why
    modern biology has rejected Lamarcks theories.   

2
The Darwinian Revolution
  • Describe how Darwins observations on the voyage
    of the HMS Beagle led him to formulate and
    support his theory of evolution.
  • Explain how the principle of gradualism and
    Charles Lyells theory of uniformitarianism
    influenced Darwins ideas about evolution.
  • Explain what Darwin meant by descent with
    modification.
  • Explain what evidence convinced Darwin that
    species change over time.
  • Explain how Linnaeus classification scheme fit
    Darwins theory of evolution by natural
    selection.
  • Describe the three inferences Darwin made from
    his observations that led him to propose natural
    selection as a mechanism for evolutionary change.
  • Explain how an essay by the Rev. Thomas Malthus
    influenced Charles Darwin.
  • Distinguish between artificial selection and
    natural selection.
  • Explain why an individual organism cannot evolve.
  • Describe the experiments that supported Reznick
    and Endlers hypothesis that differences in
    life-history traits between guppy populations are
    due to selective pressure based on predation.
  • Explain how the existence of homologous and
    vestigial structures can be explained by Darwins
    theory of natural selection.
  • Explain how evidence from biogeography supports
    the theory of evolution by natural selection.
  • Explain the problem with the statement that
    Darwinism is just a theory. Distinguish between
    the scientific and colloquial use of the word
    theory.

3
CHAPTER 22DESCENT WITH MODIFICATION
4
What is evolution?
  • Process that has transformed life on Earth from
    its earliest forms to the enormous diversity of
    today
  • Most convincing case for evolution was published
    by Darwin in 1859 On the Origin of Species by
    Means of Natural Selection

5
Historical Context of Darwins Life and Ideas
6
Western Culture Resisted Evolution
  • Plato Idealism Prefect and perceived worlds
  • Aristotle Questioned Platos dualism but
    believed species fixed and prevailed for 2000
    years
  • Range from simple to complex (scala naturae)
  • Judeo Christian view
  • Carolus Linnaeus Father of taxonomy (naming and
    classifying organisms) but believed species were
    permanent creations only to support religious
    beliefs

7
Cuvier, Fossils, and Catastrophism
  • Fossils Relics or impressions of organisms from
    the past, usually preserved in rock
  • Fossil record provides evidence that earth has
    had a succession of flora and fauna
  • Usually found in sedimentary rock (layers upon
    layers of soil, sand, mud, etc.)

8
Cuvier Father of paleontology (study of fossils)
  • Realized lifes history was recorded in
    fossil-containing strata and documented
    succession of fossil species in Paris Basin
  • Each stratum characterized by a unique set of
    fossil species oldest stratum most dissimilar
    to modern life forms
  • From stratum to stratum, new species appeared and
    others disappeared

9
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10
Catastrophism Theory that major changes in the
Earths crust are the result of catastrophic
events rather than from gradual processes of
change
  • Periodic localized catastrophes resulted in mass
    extinctions
  • Following extinctions, region becomes repopulated
    by foreign species immigrating from other areas

11
Geological theories
  • Gradualism James Hutton profound change is
    the product of slow, continuous processes

12
  • Uniformitarianism Theory that geological
    processes are uniform and have operated from the
    origin of Earth to present (Charles Lyell)

13
Lamark
  • Proposed Mechanism By Which Organisms Evolved
  • Use and disuse Those body organs used
    extensively to cope with the environment become
    larger and stronger while those not used
    deteriorate
  • Inheritance of acquired characteristics
    modifications an organism acquired during its
    lifetime could be passed along to its offspring

14
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15
Voyage of the Beagle
  • While ships mission was to chart South America
    (SA) coastline, Darwin made observations
  • SA flora and fauna were distinct from European
    flora and fauna
  • Temperate species closer to tropical species than
    temperate species in Europe
  • SA fossils were distinctly SA
  • Most animal species on Galapagos are unique to
    those islands, but resemble species living on SA
    coastline

16
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17
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18
Origin of Species
  • Descent with Modification (evolution)
  • Unity in life with all organisms related through
    descent from ancestral population
  • Diverse modifications (adaptations) accumulated
    over millions of years as descendants moved into
    various habitats

19
Darwins view of Evolution Branches at the end
demonstrate the diversity of the species
20
Natural Selection and Adaptations
  • Observation 1 All species overproduce

Flowers or Seeds
21
  • Observation 2 Most populations are normally
    stable except for seasonal fluctuations
  • Observation 3 Natural resources are limited
  • Inference 1 Struggle for existence allows for
    survival of only a fraction of offspring
  • Food, water, and space

22
  • Observation 4 Variation exists in population
  • No spot on the ladybugs below is the same as
    another

23
  • Observation 5 Much of this variation is
    heritable
  • Inference 2 Those individuals best fit to
    survive will produce more offspring than those
    less fit to survive
  • Inference 3 Unequal ability of individuals to
    survive and reproduce will lead to a gradual
    change in populations, with favorable
    characteristics accumulating over generations

24
  • Gradualism Evolution occurs by a gradual
    accumulation of small changes and mechanism of
    modification is natural selection
  • Populations Group of interbreeding individuals
    belonging to a particular species and geographic
    location are the smallest unit that can evolve

25
Evidence
  • Biogeography Geographical distribution of
    species
  • Islands have many endemic species which are
    closely related to species on the nearest
    mainland or neighboring island

26
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27
The Fossil Record
  • Many transition fossils have been found that link
    ancestral species to modern forms
  • Fossil record supports other kinds of evidence
    about phylogenetic tree
  • Prokaryotes are placed as ancestors of all life
    by evidence from cell biology, biochemistry, and
    molecular biology
  • Fossil evidence shows chronological appearance of
    vertebrates fishes, amphibians, reptiles, then
    birds, and mammals

28
Comparative Anatomy Anatomical similarities
among species grouped in the same taxonomic
category as a reflection of common descent
  • Homologous structures similar because of common
    ancestry

29
Vestigial organs rudimentary structures of
marginal or no use to an organism
  • In the early 1900s these structures were
    considered useless. Today there is at least 1
    known function for each.

30
  • Comparative Embryology Closely related
    organisms go through similar stages in their
    embryonic development gill slits develop into
    eustachian tubes in humans

31
Molecular Biology An organisms hereditary
background is reflected in its genes and their
protein products
  • Sibling similarity
  • Two closely related species should share a great
    proportion of their genes and proteins
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