Download Dar win` s J our ney and R evolution

Dar win’ s J our ney and R evolution
BIO101 Fall 2011
Key Terms:
Evolution
Adaptation
Natural Selection
Evolutionary Tree
Heritable
Artificial Selection
Key Questions:
• How did Lyell’s ideas influence Darwin?
• In what ways were Lamark’s ideas revolutionary? In what way do Lamark’s ideas fail?
• Why is variation needed for evolution to happen?
• Can descent with modification explain the diveristy of life? How?
Lecture Outline:
Descent with Modification
Early ideas about living organisms
Made by God; no changes or extinctions
Georges Cuvier – extinctions and changes in fossil record
Charles Lyell – changes in geology
Georges Louis Leclerc de Buffon & Erasmus Darwin proposed species changes in 1700s
Thomas Malthus notes that human population increases geometrically
Jean-Baptiste de Lamarck's ideas that species change over time
“use and disuse”
“inheritance of acquired characteristics”
Charles Darwin and his voyage on the HMS Beagle, 1831-36
observations of many organisms in many places, notably the Galapagos islands
hypothesis: islands were colonized by ancestral bird from S America that then diversified
Alfred Russel Wallace proposed essentially the same ideas as Darwin
Observation #1: There is variation within a species
Observation #2: Many traits are inherited
Observation #3: Populations have the capacity to increase exponentially
Observation #4: Natural resources are limited, so populations maintain a fairly constant size
Deduction #1: Individuals with helpful variations are more likely to survive and reproduce
Deduction #2: Favorable traits accumulate over time.
Deduction #3: Accumulation of variation over many generations is evolution
Natural Selection
over time, organism’s adaptations make it a better fit for the environment
Artificial Selection
Individuals don’t evolve; populations evolve
No guiding “plan”