L02 Darwin Flashcards
How long was the change over (from not believing in evolution to believing)
10-20 years
What did Darwin kill in biology
- essentialism
- teleological explanation
what was Darwin’s reasonable mechanism for evolution?
natural selection
-unlike Lamarck and chambers who had a good reason to think evolution happened but didn’t have good mechanisms
How did Darwin explain design and purpose of organisms
- in a natural way
- movement of function and purpose
- banished teleological explanation
What did his father send him to school for?
- University of Edinburgh to study medicine
- he was horrified by surgery and lectures
- liked chemistry
What did Darwin then become interested in?
- natural history
- geology
Tried to become part of the ____
clergy (cambridge)
-did not take this seriously but read Paley’s natural history. This started his interest in functional biology
What was his role on the Beagle?
- said that he was the ships naturalist
- this was doubted, might just have been the captains social companion
Why did the captain need a companion?
- captain would not interact with the crew much due to intellectual gaps
- high suicide rates
Who did he marry and where did he move to
Emma Wedgewood, moved to Down House (London)
What did he publish while in london?
- The Voyage of the Beagle
- 5 volume work on the vertebrates he collected
- The Structure and Distribution of Coral Reefs
What was evolution called when Darwin started thinking about it (secretly)
species transmutation
Possible causes for Darwin’s Sickness
- Chagas’ Disease: transmitted from a beetle that he recorded as biting him
- Crohn’s Disease
- Psychosomatic: caused by internal conflict/stress. Terrified of the response to his ideas.
What kind of scientist did Darwin consider himself as
-Geologist, not Biologist
What was his first scientific book on
-structure/distribution of coral reefs
What did Darwin study for 8 years at Down House
barnacles
Darwin’s main book on evolution
The origin of species
how long before the publication of “the origin of species” did Darwin start thinking about evolution
23 years
- July 1873
- Darwin began a notebook on species transformation, the observations and material he had gathered on his voyage convinced him that evolution occurs
How did he search for a cause of evolutionary change
-wondered what natural phenomenon could select for certain inherited traits the way artificial selection (plant/animal breeding by humans) could
What did Darwin decide was the cause for evolutionary change
- adaptation to the environment
- called it ‘natural selection’ or ‘contrast artificial selection’
Why did Darwin keep sketch and essay a secret?
- was too short wanted it to be longer
- wanted to become expert before publishing such a radical idea
- same year Chamber’s vestiges was published, didn’t want to be the centre of arguments
Who encouraged Darwin to write 1000 page book “Natural Selection”
Hooker and Lyell
Hooker: convinced
Lyell: not convinced but thought that evolutionary ideas were important
What did Alfred Russel Wallace do?
- wrote brief outline of evolution and sent it to Darwin for his opinion
- unaware that Darwin had been working on same issue
- Darwin realized he had been scooped
What was Alfred Russel Wallace’s outline on
- a discontinuity of the flora and fauna past a specific area
- now understand that this is continental drift
What 3 papers were read at a meeting after Darwin had realized he had been scooped
- 5 page summary of Darwin’s ideas
- Copy of Darwin’s letter to Asa Gray from 1857 to show he had not stolen Wallace’s ideas
- Wallace’s paper
What did Darwin write when he abandoned “Natural Selection”
“The Origin of Species”
-shorter presentation, written when he was in bad health
What was the “Origin of Species” mainly about
- artificial selection
- natural selection
- common descent explaining similarities in systematic groupings, embryological similarities, vestigial organs, geographic distribution of organisms and fossil sequences in the stratigraphical column
What did Darwin propose as causes of evolutionary change
- Natural selection
- -> seen lots of different breeding
- -> did not know anything about genetic variance so what caused variance was a mystery to him - Use and Disuse
- -> accepted some of Lamarckian inheritance. Didn’t think it was the main force but thought it was possible to lose traits based on disuse
Types of variation
- Sports: large and conspicuous barriers.
- -> an animal that is different from another in its species - Individual Variation: refers to variation that is small and incremental (now referred to as continuous variation)
Darwin’s view on heredity
- thought there were hereditary particles in the body called gemmules
- carried the experience of parents
- his genetics were the weak part of the argument
Two debates that arose because of Darwin
- Whether Darwin was correct or not
2. If he was correct, what the meaning of evolution might mean for society, morality, and philosophy
Fleeming Jenkin
Said that Darwinian evolution is inconsistent with what is known about heredity and the nature of species
-thought heredity couldn’t vary past a limit of an average like the centre of a sphere (essentialism thinking)
Fleeming Jenkins view of large genetic variants (sports)
- Blended inheritance, didn’t think that selection could happen as there would be no organisms that resembled the parent as they would all move to uniformity.
- Large genetics spots blended out
Darwins responses to Fleeming Jenkin
-refuted analogy of spare as perhaps the sphere can move so maybe so that the variation was not outside the limit
A.W Bennet
- Natural selection cannot fashion complicated adaptations requiring many steps
- Depended on each variance having advantage over existing variance
Darwin’s Response to A.W Bennett
- wrote book on the butterflies in the amazon river
- pierids butterflies living with toxic heliconid butterflies. Pierids mimicked the heliconid butterflies (over all variation)
A.W Bennets response to the butterfly rebuttal
- how long would it take to go from one phenotype to the other
- would each step confer with selective advantage to the mimic?
Darwin couldn’t rebuttal this but was later shown that these small events would be important
Sir William Thomson (Lord Kelvin)
- Earth has not been habitable for long enough for Darwin evolution to have occurred to reach the variation that is currently seen
- Sun doesn’t have enough energy reserves to have existed for that long
- estimated that gravitational collapsed (causing sun to burn) has been occurring for 20-40 million years
Darwin rebuttle to Lord Kelvin
-maybe if the earth was more violent in its early life then evolution would have been accelerated
What happened in 1900’s
-Darwinism is dead. Darwinism refers to natural selection (not evolution, evolution was accepted)
