1. Historic Context
Plato and Aristotle believed that organisms were perfectly formed and adapted to the world
Judeo Christian theology believed:
that the world is 6,000 years old
species were created individually
Natural Theologians searched for God’s plan through the study of nature

2. Carolus Linnaeus founder of taxonomy and binomial nomenclature
Clustered similar organisms into categories, he did not assume any evolutionary relationship based on this classification scheme
Paleontology developed by Cuvier ( )
He noticed that species appear and disappear in the fossil record
He did not use this to support evolution, but developed catastrophism

3. Principles of Populations
Thomas Malthus (1798) published that populations increase faster than environment can handle
Capacity to over-reproduce is seen in all species
Eventually populations stop increasing in size and reach a steady state (carrying capacity)

4. Geology
Hutton ( 1795) theory of gradualism that major changes are the result of slow small changes
Lyell (1830) geological changes throughout time have been subjected to the same forces
Conclusions:
If geological changes are slow earth is older than 6,000 years old
the slow changes can build and result in profound environmental changes over time

5. Relating geological evolution to biological evolution:
Theories of biological evolution begin in the late eighteenth century
Lamarck was the first to propose a mechanism that related environment to biological changes (1809)
Use and Disuse
Inheritance of Acquired Characteristics

6. Darwin Sails on Beagle at 22
Noted that flora and fauna of islands off of SA were more like continental species than those of other islands with similar climate and habitats
Contributions of Lyell and Malthus along with his observations lead him to his mechanism for evolution

7. Evolution What is evolution?
All of the accumulated changes that have occurred over time
Darwins definition: Descent with modification
Life’s history is a tree with different branches
Forks of the tree represent common ancestors
Most closely related organisms share common paths on the branching tree

8. Darwin used Linnaeus’ taxonomic classification scheme to connect diversity of life
Kingdom > phylum > class > order > family > genus > species

9. Mechanism : Natural Selection
Fact 1: Over-reproduction occurs in nature
Fact 2: Populations do not increase exponentially
Fact 3: There are limited natural resources (food, shelter)
These facts are seen in Malthus’ works on populations

10. Inference 1:
struggle for survival ensues
Fact 4: Variation exists in populations
Fact 5: Much of the variation is heritable
Fact 4 was physically observed. Darwin’s weakness was the 5th fact
Inference 2:
Organisms with the best variations survive the struggle for life
Inference 3:
Unequal survival of organisms with different variations leads to favorable variations accumulating over time

11. Key Concepts
What is the raw material necessary for the mechanism of Natural Selection?
Heritable variations
What is the smallest unit of evolution?
Populations
Darwin incorporated Lyell’s gradualism into biological evolution combined with Malthus’ observations regarding populations

12. Examples of Natural Selection
Grants on the island of Daphne Major
observed shifts in the frequency of beak sizes over short periods of time
Peppered moths
Antibiotic resistance in bacteria
How do the genetic variations arise in nature?

13. Evidence for Evolution
Artificial selection
Island biogeography
Fossil record
Taxonomy
Comparative Anatomy
Vestigial Structures
Comparative Embryology
Molecular Biology

22. Eye sockets in blind salamanders