Transcript Evolution - Kent City School District

Evolution
Ideas That Shaped Darwin’s
Thinking
15-2
At the time…
• Most people believed the Earth was
only a few thousand years old
• Most believe species and the Earth has
NEVER changed
• Most, but not all! New fossil evidence
begins to shift many people’s veiwpoints
Geology Perspective
• Hutton- proposed that Earth changes
over time, including the rock cycle and
other natural forces shape the earth;
proposed the Earth is millions of years
old
• Lyell- proposed how volcanoes and
other geologic forces can build and
destroy landscapes
Darwin’s Take…
• Darwin thought if the Earth could
change, why couldn’t life change?
• Also, if the Earth is changing, plants and
animals MUST change to survive!
• This begins his new theory of evolution.
Economy/Ecology Perspective
• Malthus: reasoned that if the human
population continued to grow
unchecked, food and shelter will run out
(carrying capacity)
• This idea alone sprung forth the steps to
natural selection.
Other Evolution Hypotheses
• Lamarck: stated that selective use or
disuse of organs causes organisms to
acquire or lose certain traits…
• Then, these traits can be passed on to
offspring
• Ex:Crab Claw (pg. 376)
• Is this a valid hypothesis? Can you think
of your own example?