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BIO120 Lecture 2 (Darwin's Impact (Mechanism of natural selection…
BIO120 Lecture 2
Darwin's Impact
Mechanism of natural selection
Variation
Heredity
Selection
Why inheritance of acquired characters is wrong
Inheritance only occurs via gametes (somatic cells don't function as agents of heredity
Genetic information flows from DNA to protein, never reverse
Key Ideas
Evolution occurs @ population level
Variation is due to random mutations and the environment is selective
Survival of the fitter not the fittest
Implications
Dynamic universe
Phenomenon without purpose --> did not sit well with many/loss of morality
Darwin's Process and Ideas
Discovered idea of natural selection w/ Wallace, defeating idea of "inheritance of acquired characters"
Developed idea of gradualism w/ Lyell (idea that universe is dynamic, not static) -- present-day geological processes can explain the history of earth
Developed idea of varying species w/ mockingbirds on Galapagos islands
Malthus discussed potential for exponential growth in human population, leading to struggle to survive
Darwin realized this applied to all populations
Realized that not all individuals will survive and reproduce as well as others (favourable variations are preserved; unfavourable are destroyed)
Accumulated evidence for 20 years; didn't publish until 1844 when he received work from Wallace
1859 - Origin of Species published --> became coffee table book; popular
Origins of evolutionary thought
Paley's argument - in a desert, a random rock serves no purpose, but a random watch does (it's complex and functional) --> trees possess complex adaptations to dry climates so it should have a designer
Lamarck was the first to talk about "evolution" but did so w/ the incorrect explanation "inheritance of acquired characters", i.e. what individuals do in their lifetime will be passed onto the next generation