Transcript 15-1 The Puzzle of Life`s Diversity

Early Ideas on
Evolution
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Evolutionary Timeline
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Carolus Linnaeus – first to
group similar organisms and
assign them Latin names
(taxonomic classification
system)
 Two word name (Genus
species)
 Known as binomial
nomenclature
 Originally believed all
organisms were fixed and did
not change; did not believe
that living species could
evolve from a common
ancestor
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James
Hutton - Scottish geologist
Described the geological forces
that have changed life on Earth
over millions of years (erosion,
earthquakes, volcanoes, mountain
building)
 Changes in Earth’s crust due to
slow continuous processes
 Idea known as Gradualism
 These changes caused certain
species of life to become extinct.
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Thomas Malthus –
economist who said that, in
nature, plants and animals
produce far more offspring
than can survive
 Poverty, famine, disease
result from overpopulation
 Darwin would eventually
use this idea to help explain
natural selection and
survival of the fittest
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
Jean-Baptiste Lamarck –
French naturalist that
proposed that all organisms
evolved toward complexity
and perfection
Stated that changes are
adaptations to environment
acquired in an organism’s
lifetime
 Said acquired changes were
passed to offspring

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Example – bird ancestors
desired to fly so they tried
until wings developed
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Lamarck’s Theory of Evolution
Inheritance of Acquired
Characteristics
Proposed that by selective use or
disuse of organs, organisms acquired
or lost certain traits during their
lifetime.
 Those traits could then be passed on
to their offspring.
 Over time, this leads to new species.
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Lamarck’s Theory of Evolution

Use & Disuse -
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Giraffe’s neck got
longer from stretching
Organisms Could
Change The Size Or
Shape Of Organs By
Using Them Or Not
Using Them
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Lamarck’s Theory of Evolution

Inheritance Of Acquired Traits
◦ Traits Acquired During Ones Lifetime
Would Be Passed To Offspring
Clipped ears of dogs could be passed to offspring!
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Lamarck’s Mistakes
 Lamarck
Did NOT Know how
traits were inherited (Traits are
passed through genes)
 Genes Are NOT Changed By
Activities In Life.
 Change Through Mutation
Occurs Before An Organism Is
Born.
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Charles Lyell – geologist;
published Principles of
Geology which advanced and
popularized ideas of Hutton
 Proposed theory of
Uniformitarianism
 Geological processes
occuring at a uniform rate
were responsible for
building & wearing down
Earth’s crust
 Proposed that the Earth
was millions of years instead
of a few thousand years old

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Georges Buffon – studied fossils
to propose that species shared
ancestors instead of arising
separately
 Species were created, but were
not perfectly adapted and
gradually changed over
generations by “degenerating”
from the forms given to them
by God
 Had no suggestion for how
these changes occurred
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Alfred Russel Wallace -if an
animal has some trait that
helps it to withstand the
elements or to breed more
successfully, it may leave
more offspring behind than
others; the trait will become
more common in the
following generation, and
the generation after that
(natural selection)
 Considered Darwin’s “codiscoverer” of evolution by
natural selection
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