Charles Darwin
Modified: 2025-01-08 6:46 PM
- Another poor student
- Dropped out of medical school at the University of Edinburgh
- The grisly operations sickened him
- He then went to Christ's College Cambridge to become a minister
- There, he met John Stevens Henslow who helped arrange passage on the HMS Beagle
- Darwin's father objected but relented
- HMS Beagle
- Captain Robert FitzRoy (last captain had committed suicide)
- Darwin was supercargo-could talk to Darwin
- The rules and regulations of the Royal Navy prohibited captains from engaging in any personal interactions with officers and crew. Because naval captains were the supreme authorities on their vessels, the British Admiralty believed that any personal relationships would undermine discipline. Darwin (or any other civilian) was exempt from that regulation. In fact, Darwin and FitzRoy were amiable dinner companions throughout the Beagle’s nearly five years at sea.
- Five year voyage: South America, the Galapagos, New Zealand, Australia, South Africa, South America, England
- Darwin collected specimens and mailed them back to England when he could
- Back in England he tried to make sense of his observations
- Could not use creationist or directive mechanisms
creationism: the belief that God created all things in substantially the same form as they presently exist and that they did not evolve from distant ancestors.
- Human populations could grow more quickly than food supply
- Darwin came up with natural selection
natural selection: the competitive process by which organisms that are better adapted to survive the environmental conditions around them survive, and thus, reproduce more successfully leaving more offspring, and gradually altering the population characteristics of their own species.
- Natural selection depends on random change not directed change
- Darwin had been taking his time thinking about evolution
- Alfred Russel Wallace sent Darwin a letter about his own ideas about evolution
- Darwin's friends and colleagues worried about Darwin losing scientific priority
- So they arranged for both papers to be read at the:
- Linnean Society 1858 (neither Wallace nor Darwin were there)
- No one really took notice
- But next year, Darwin published:
- Origin of the Species by Means of Natural Selection (1859)
- Sold out in 1 day! (1250 copies) One sold for $170,000 in 2009
- This is the point in class where I offer to buy any first editions you may have at home for $10 :-)
- Lord Kelvin did not agree (Earth too young, he thought)
- He was wrong about the age of the earth (see above)
- Mechanism of evolution unknown in Darwin's day
- The modern synthesis (see above) had not yet occurred
- Darwin and Mendel did not know about each other's work
- Darwin waffled in later editions, uses Lamarckism
- Thomas Huxley, (Darwin's bulldog) however, fought to preserve, promote, and revise Darwin's theory
- Modern Synthesis of Biology: Evolution AND Genetics
- Modern Evolutionary Theory
- Reproduction as key to natural selection
- Spencer's "survival of the fittest" is NOT the mechanism
- Simply surviving will not get genes from one generation to the next
- Reproduction will move genes across generations
- Other Selective Mechanisms (Price & Perez, 2016)
- Genetic Drift
- variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce (Oxford Languages)
- Dominance
- genetic mechanism where in certain alleles the presence of one allele determines the phenotype
- Relationships Among Allelic Pairs
- Evolutionary Developmental Biology
- The interaction of evolution and development that posits the presence and action of highly conserved genes across widely divergent species
- Sexual Selection
- The use of extreme characteristics or behaviors by males that improve their fitness but but them at risk for predation.
- Kardas PhD Dissertation title (a sexual selection experiment): Female preference for male coloration and size in the guppy, Poecilia reticulata.
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