Transcript Early Ideas About Evolution

Early Ideas About
Life & Evolution
Creationism
• Creationism is basically the creation story
from the Bible.
• Archbishop James Ussher of Armagh
calculated the date and time of creation to
be Sunday, October 23, 4004 B.C.
• In these days, people believed that living
forms were immutable – unchanging – and
that what you saw around you was the way
it was when the Earth was created.
• Fossil evidence works against a strict
belief in the world being only 6000yrs old.
Catastrophism
• Baron Georges Cuvier studied fossils and noted
that many of the fossils were of creatures no
longer living on the planet.
• He also noted that the more complex forms of
these fossils were closer to the surface and
that they got less complex the deeper you dug.
Also – many of the fossilized creatures in one
layer of the earth did not resemble creatures in
the neighbouring layers.
• Instead of evolution and a flow of form, he
explained it with the concept of catastrophism.
Local catastrophes (like floods) would wipe out
the organisms of that time and they would be
replaced with newly created forms.
• It explained the fossils but not the increasing
complexity.
Actualism
• James Hutton was a Scottish
geologist and naturalist who
proposed the idea of actualism in
which he stated that the same
geological processes occurring in
the present also occurred in the
past.
• This idea would go on to help form
the idea of uniformitarianism and
affect Darwin’s theory of Natural
Selection.
Uniformitarianism
• Sir Charles Lyell put forth the
concept of uniformitarianism.
• In this, he stated:
• The Earth has been affected by the
same processes in the past as what are
occurring presently.
• Geological change is slow and gradual
rather than sudden and catastrophic.
• Natural laws and processes are
constant and eternal – the operated with
the same intensity in the past as they do
in the present.
Georges Buffon
• Georges Buffon was the first
scientist to suggest that species
could change over time and that
these changes could lead to the
formation of new species.
• He brought the idea of evolution into
the realm of science.
• He developed a concept of the "unity
of type," a precursor of comparative
anatomy.
The Principle of Population
• Thomas Robert Malthus put forth his principle of
population in which he points out the problem of
unchecked population growth and its effects.
• On the subject of unchecked populations:
“The power of population is indefinitely greater than the power in the earth to
produce subsistence for man. Population, when unchecked, increases in a
geometrical ratio. Subsistence increases only in an arithmetical ratio.”
• And the consequences:
•
“The power of population is so superior to the power of the earth to produce
subsistence for man, that premature death must in some shape or other visit
the human race.”
Malthus argued that population was held within
resource limits by two types of checks: positive
ones, which raised the death rate, and preventative
ones, which lowered the birth rate.
• Darwin would use these ideas greatly in terms of
survival of the fittest.
Acquired Characteristics
• Lamarck was the first biologist to recognize the
role of the environment in the changing of a
species in his theory of acquired characteristics.
• In this he states that animals strive to survive
through the use or disuse of various parts of
their bodies. Those that are used will be
accentuated and become stronger while those
that are not used will whither and disappear.
• The enhanced traits will then be passed on to the
next generation.
• The problem is that Lamarck has the driving
force of change within the control of the
organism – not the environment. It is as if to say,
“If you want it bad, you can develop the traits
needed to survive.”
Next Stop…Evolution!
• Charles Darwin used parts or all of
these ideas to help him form his theory
of evolution through natural selection.
• As we go through the ideas Darwin put
forth, you will be able to make
connections back to these ideas.
That’s All I Got…