Development of Evolutionary Theory
Served as both a guide and justification for human actions
Origin myths are critical to a society's self-definition
So when threatened, there's a strong reaction
All humans are descendent of Adam and Eve
Created by God
9AM, October 23rd, 4004 BCE
Humans are considered separate from the natural world
6000 yr chronology leaves no time for evolution
Should be no extinct ancestral species
Development in Biology/Geology
Classification of plants and animals
Placed humans in the order Primates
Progressionism and natural theology
Tried to fit biology to a religious framework
"Ladder of Creation"
Order of creation of "races"
Western Europeans at the top
God, angels, heaven, humans, beasts, plants, flame, rocks/dirt
Theory of acquired characteristics
e.g. Giraffe that stretches its neck and thus offsprings have longer necks
Evolution had to be put within 6000 yrs
"Principles of Geology"
Idea that the earths form was derived from SLOW and GRADUAL processes
of uplift, erosion, and deposition
Earth forms were created by cataclysmic floods, volcanic eruptions,
Had a strong influence on Darwin
Earth was estimated to be a whole million years old
Failed med school
Worked on the Beagle as a biologist
Mapped the coast of South America
Observed geographical variation in related species
Refined his concept of observation Collection of fossil Glyptodons
Observed geological processes of uplift and erosion
Married a very rich lady
Influenced by Thomas Malthus
Struggle for existence
More offspring are born than what can survive
"Population grow exponentially, while food production grows arithmetically"
***5 major points of Darwinian evolutionary theory***
1. Organisms produce more offsprings that can survive to reproduce
2. Because of high numbers in individuals in a species, there must be a high
3. Individuals in each species vary in their characteristics
4. Variants that fit their environment better will be favoured over those less fit.
Fitness is defined by differential reproductive success. By inheritance,
better fit individuals will pass their beneficials characteristics to their
offsprings, which will survive and reproduce in greater quantity.
5. Following generations will continue to exhibit and refine adaptations realized
by their ancestors.
Origins of Species
Two unanswered questions
What is the source of individual variation?
How are characteristics are inherited?
False idea of "blending inheritance" where characteristics from each parents
are mixed like liquids
Alfred R. Wallace
Developed similar theory as Darwin, from his work in Southeast Asia
They jointly publish a paper on evolution in 1858
Major scientific challenges