Ch. 18 Evolution 1
Idea to explain biodiversity
• Creation: was the only idea for several millennium
• 1619: Lucilio Vanini
• Darwinian evolution: accumulated inherited changes in a population over time
• He didn’t come up with it, he came up with the mechanism of natural selection, not
evolution itself. Natural selection is what projected it to what it is today
• Darwin, Malthus,
• Lyell: principles of geology, suggested that the earth was not 4,000 years old, but
beyond what we can imagine in age. It just evolved.
• Influenced darwin.
• Lamarck: came up with first theory of evolution. Species do change over time, becuase
they have acquired traits of time
• The ancestrial giraffes were short necked...when food became scarce and they had
to reach higher and higher in the trees for food, the neck began to stretch over the
....however, Jewish people remove foreskin, yet have not evolved the complete
• If your parents were good at bio, does that mean you will be?
• Fluched idea
• Darwin: giraffes have long necks because there used to be long and short necks, but when
food became scarce, the shorter necked ones could not reach the food, and thus became
extinct, unlike the long necked who reached the food and maintained their life
• Individuals born with traits that make them best adapted for their environment are also
the ones most likely to survive and produce offspring
• Overproduction: organisms produce more offspring that can survive to
• Limits on population growth: growth is logarithmic, not exponential. Resources
are limited so there is a “struggle for existence”
• Variation: individuals within species vary (some are more ‘fit’ than others).
The raw material for evolution
• Differential reproductive success: natural selection acts on variation
← ** reproduction is the key to natural selectionL the most fit individuals produce the most