LEQ: Who was Charles Darwin and what ideas influenced him?
http://www.pbs.org/wgbh/evolution/library/11/2/e_s_1.html
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Lemark – 1st to propose an evolutionary
theory; he incorrectly suggested that acquired
traits (like big muscles from lifting weights)
are inherited
http://www.pbs.org/wgbh/evolution/li
brary/11/2/e_s_2.html
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HMS Beagle – 1831 @ age of 22; 5 year voyage around
the world; collected thousands of specimens of fossil
and living plants/animals; noticed geological features
Lyell – Darwin read Lyell’s book, “Principles of Geology”
which states that natural forces gradually changed the
Earth’s surface - this explained how fossils of snails
could be found on mountain tops or whales in deserts
(he knew these forces were still taking place today)
Wallace – mid 1850’s; British naturalist conceived a
theory similar to Darwin’s; He shared his ideas with
Darwin and spurred Darwin to publish his theory
On the Origin of Species – 25 years of analysis is
documented in the book; presents ideas about natural
selection and descent with modification
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Malthus – predicted that human population
will grow faster than the space and food
supplies needed to sustain it, as a result
population is limited by famine and disease;
Darwin deduced that because natural
resources are limited for all organisms, the
production of more individuals than the
environment can support, leads to a struggle
for existence – where only some species
survive to reproduce
http://www.pbs.org/wgbh/evolution/li
brary/02/5/quicktime/l_025_01.html
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Artificial selection –
Farmers have shaped
the evolution of plants
and animals by
selectively breeding
particular organisms
to obtain desired
traits; Darwin thought
– if people can do
this, maybe this could
occur naturally
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Natural Variation – Members of a population
vary in their characteristics; various
characteristics make some individuals better
adapted to their environment
Inheritance of traits – the control of what
characteristic is expressed depends on the
organism’s genetic make-up; this
information is passed from one generation to
the next
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Natural Selection – Every environment has
limited resources; in a varied population,
individuals that have characteristics/traits
that make them well adapted to their
environment will survive to reproduce,
leaving more offspring with the same well
adapted traits. Not adapted = no survival
and/or no reproduction, leaving few/no
offspring
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Diverse forms of life have arisen by descent
with modification from ancestral species
Natural selection is the mechanism of the
modification