Transcript Theories of Evolution

Ancient History 10
Your Thoughts…
Where did we come from?
What is the difference between a
theory and a fact?
Theory vs. Fact

Theory:
 A proposed explanation whose
status is still hypothetical and
subject to experimentation.

Fact:
 A truth known by actual
experience or observation;
something known to be true.
Theories on how it began ...
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Evolutionary theory did not begin
in 1859 with Charles Darwin and
The Origin of Species.
Evolution-like ideas had existed
since the times of the Greeks
Darwin's time the idea of
evolution - called "descent with
modification“
– Not completely controversial, since
there was other evolutionary theories
had already been proposed.
Theories – The Greeks
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Greeks had a philosophical
notion of descent with
modification.
Greek philosophers argued
that all things originated from
water or air.
All things descended from
one central, guiding
principle.
– Aristotle: transition between the
living and the nonliving, and
theorizes that in all things there
is a constant desire to move
from the lower to the higher,
finally becoming the divine.
Theories- Medieval
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Talks of evolution during the
Medieval times was uncommon
• Era was dominated by the
Christian theory of creation.
• Spontaneous generation
– Living things can appear fully
formed from inorganic matter.
• Maggots came from rotting meat,
frogs came from slime, etc.
• Prevented both genetic thinking and
speculation about evolution or
descent with modification.
Theories- I. Kant 1724-1804
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His concept of descent was
close to modern thinking
– Anticipated Darwinian thinking.
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Based on similarities between
organisms
– Come from a single ancestral
source.
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Speculated that an orangoutang or a chimpanzee may
develop may evolve to the
structure of man.
Theories- C. Linnaeus 1707-1778
Father of modern taxonomy for his
work in hierarchical classification
of various organisms.
 Believed in the fixed nature of
species.

 Because of hybridization
experiments in plants, which could
produce new species.
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Support of the Christian belief of
creation
Theories – T. Malthus
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1766-1834
Theory of population growth
was in the end what inspired
Darwin to develop the theory of
natural selection.
– Populations produce many more
offspring than can possibly survive
– Poverty, famine, and disease were
natural outcomes that resulted
from overpopulation.
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Divine forces were ultimately
responsible for such outcomes.
Theories- Creation

Genesis Story (Christian Bible)
 Old testament

God created the world in 6 days and
rested on the 7th day.
 Adam (clay or dust) and Eve (Adam’s rib)
 Garden of Eden (Paradise)
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Tree of knowledge
 Sin

Taken from paradise
Theories–Darwin and Wallace
Charles Darwin and Alfred Russel
Wallace
 Developed the idea of the
mechanism of natural selection
 Darwin thought about the issue for
20+years before he first published
The Origin of Species.
 Darwin was interested in exploring
the implications of natural
selection.
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Charles Darwin: Father of Evolution

12 February 1809 – 19 April 1882
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When he was 22, he embarked on a 5 year journey
around the world, as a Naturalist on the HMS Beagle

The distribution of wildlife and fossils he saw on his
journey was later used to develop his theory of
Evolution.
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This evidence was then used to publish his theory in
his 1859 book On the Origins of Species
Evolution

Gradual change over many generations

Widely held notion that all life is related
and has descended from a common
ancestor.
Natural Selection (Survival of the Fittest)
= Random genetic mutations occur and
the “good” aspects are kept to aid survival

Failure to evolve in response to the
environmental changes can and often
does lead to extinction.
Brain Pop:
http://www.brainpop.com/scien
ce/famousscientists/charlesdar
win/preview.weml
Big Bang Theory:
http://www.youtube.com/watch
?v=B409mw3mzI4