Transcript Natural selection

Evolution and Natural Selection
4.1 Darwin and History of Evolutionary Thought
What did people believe before Darwin?
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Pre-Darwin incorrect ideas
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Carolus Linnaeus (1707-1778)
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Earth young
Species don’t change
A creator dictates adaptations to environment
Also spontaneous generation
Binomial nomenclature
Scala naturae
Adaptations become apparent
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Changed scientific thought
Who paved the way for Darwin?
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Two try to explain how organisms adapt to their
environment
Georges Curvier (1769-1832)
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Father of paleontology
Catastrophism
Jean-Baptiste de Lamarck (1744-1829)
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Inheritance of acquired characteristics
Who was Darwin?
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Darwin’s work started on a boat
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HMS Beagle
1831
Studied biogeography
Studied geology
Studied fossils
What did Darwin propose?
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Organisms related by descent
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Adaptation occurs
Geological time necessary for new species to form
Sample organisms
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Finches: adaptive radiation
Tortoises
Evolution and Natural Selection
4.2 Mechanism of evolution
What mechanism drives evolution?
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Natural Selection
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Is the mechanism, evolution is the outcome
Darwin and Alfred Wallace proposed together
1850s
“On the Origin of Species”
Populations evolve, individuals do not
What are the preconditions for natural selection?
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Variation must be present
Traits must be heritable
More individuals are produced than can survive (differential
reproduction)
Some traits are advantageous (differential adaptiveness)
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Allow for greater reproduction (fitness)
What are the outcomes of these preconditions?
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More individuals have
advantageous trait
over generations
Population becomes
adapted to local
environment over
time
Remember:
populations evolve,
not individuals!!!
Best real-time
example: antibiotic
resistance
Evolution and Natural Selection
4.3 Artificial selection and evidence for evolution
What is artificial selection?
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Same as natural selection
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Man is selector of traits
What is the evidence for evolution?
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Hypothesis vs. theory
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Theory = repeatedly
supported hypothesis
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1,000’s and 1000’s of
experiments and evidence
across MULTIPLE different
disciplines
Overwhelming support of a
hypothesis elevates
hypothesis to a _______
(AKA a ______)
Evolution is a LAW just as is
the LAW of GRAVITY
Examples of just a FEW of the many disciplines with findings that
support evolution:
Biogeography
Molecular biology
Cellular biology
Ecology
Behavioral sciences
Artificial breeding
Population biology
Sociology
Anthropology
Organic chemistry
Microbiology
Paleontology
Biogeography
Functional morphology
Comparative embryology
What is biochemical evidence?
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Use DNA, RNA, proteins, etc. to establish relationships
More conserved regions = closer relationship
What is anatomical evidence?
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Homologous structures
Analogous structures
Vestigial structures
What is fossil evidence?
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Transitional
fossils are
revealing