The History of Evolutionary Thought
01-07-10 and 01-08-10
What is Science?
The Standard Scientific Method: A hypothesis is stated, data are collected, and the
hypothesis is supported or refused.
hypothesis:
observation: gathering of scientific information by watching the phenomenon.
experimentation: testing of a hypothesis.
deduction: a conclusion that follows logically from a set of observations.

Paradigm: a conceptual framework useful for understanding a body of evidence.
Theory:
Evolution:
“gradual process in which living organisms change so that over time, descendants differ
morphologically and physiologically from their ancestors” — Charles Darwin.
Charles Darwin

Gave the world mechanism of how evolution occurs.
Natural Selection: differential reproductive success over multiple generations.
European Medieval Paradigms
Special Creation: the Earth was created by God and nothing was created again.
Fixity of Species:
The Date: (J. Ussher) the Earth was created in 4004 B.C.

Undermining the Paradigms
Carolus Linnaeus
classification scheme for plants and animals.
taxonomy:
binomial classification system: a genus and a species. Homo sapiens
Compte de Buffon
Erasmus Darwin
Jean-Baptiste Lamarck
Inheritance of Acquired Characteristics: Individuals can evolve during their lifetimes
and pass on these characteristics to their offspring.
J. Cuvier
Paleontologist

catastrophism: theory that there have been multiple creations interspersed by natural
disasters.
James Hutton
proposed uniformitarianism:
Charles Lyell
“Principles of Geology”
Added more to uniformitarianism.
These processes acting on the Earth are slow and have shaped the crust gradually.

Summary of Undermining the Paradigms
challenged the idea of special creation and fixity of species.
dismantled the Great Chain of Being through catastrophism and extinction.
gave Earth a long history of slow, gradual change.
Charles Darwin
Sailed on the HMS Beagle to Galapagos Islands to study flora and fauna.
Charles Darwin
On Galapagos found different kinds of finches that were modified depending on habitat
and diet.
Adaptive Radiation:
Alfred Russel Wallace
In 1858 submitted to Charles Darwin a paper describing natural selection.

Evolution by means of Natural Selection
All species are capable of producing offspring faster than the food supply is able to
increase.
All living organisms show variation.
Individuals with favorable variations are most likely to survive and leave offspring,
known as differential reproduction.
Favorable variations are inherited and passed on to the next generation; less favorable
variations tend not to be. These individuals are said to have higher fitness.
Fitness: reproductive success. The ability to survive to reproduce.
Over long periods of time, these successful variations can produce great differences that
result in new species.
the key: an individual has to survive to reproduce not just survive.
Adaptation:
Evolution: occurs at the population level.
Population:
Natural Selection occurs at the level of the individual.