Download Darwin`s Theory of Evolution

Evolution
and Darwin’s Contribution
"The natural history of these islands is eminently curious,
and well deserves attention."
-- Charles Darwin, from Voyage of the Beagle, 1845
Evolution
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The processes that have transformed life on earth from its
earliest forms to the vast diversity that characterizes it
today.
A change in the genes, caused by mutations.
One gene can change the shape of a skull. It can lengthen lifespans.,
restructure the color pattern on a wing, or create a race of giants.
~Edward O. Wilson
Charles Darwin

Darwin set sail on the H.M.S.
Beagle (1831-1836) to survey
the south seas (mainly South
America and the Galapagos
Islands) to collect plants and
animals.

On the Galapagos Islands,
Darwin observed species that
lived no where else in the world.

These observations led Darwin
to write Voyage of the Beagle, a
travelogue of his journeys.
Charles Darwin

From the observations on his trip
he started writing
On the Origin of Species by Means
of Natural Selection.

It took him 25 years to finally
publish the book. Published in
1859.

Two main points:
 Species were not created in their
present form, but evolved with
modifications from ancestral
species.
 Proposed a mechanism for
evolution: NATURAL SELECTION
James Hutton (1726-1797)
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One of the first geologists
to challenge the age of the
Earth.
Proposed the layers to
have been laid down and
shaped over millions of
years.
" ...no vestige of a
beginning, no prospect
of an end."
Charles Lyell (1797-1875)
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Famous geologist of
Darwin’s time.
Darwin was reading his
book, Principles of
Geology (1830), while on
the HMS Beagle.
Covered questions
pertaining to orderly
change in time from
geological evidence and
fossils.
Discussed similarity of
fossils from different
continents.
Jean-Baptiste Lamarck
(1744-1829)


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First to hypothesize a mechanism for changes in
organisms over time and realize that they were adapted to
their environments.
But, his Theory of Inheritance of Acquired Characteristics,
incorrectly stated that animals can pass on traits that they
developed during their lifetime.
Coined the term “Biology”.
Thomas Malthus (1766- 1834)

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Social Economist, author
of Essay on the Principles
of Population (1798).
Argued that food supply
increased in a linear
fashion, while population
increased “geometrically”
(exponenetially).
Example of limited
resources causing
competition.
Natural Selection
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Resources are limited and this creates competition.
Organisms produce more offspring than can
survive.
Variation exists amongst the individuals of a
species.
Individuals with favorable traits are more likely to
leave offspring better suited for their environment.
Over time, those individuals with the favorable traits
will make up more of the population and could
become a separate species.