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32 Cards in this Set
- Front
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When did the idea of species changing over time arise? |
It arose even before Darwin. Example: 1. Anaximander (610-546 BC): Early humans burst from the insides of other animals. Humans could not have survived extended infancy in the primordial world. 2. Augustine of Hippo (354-430 AD): To suppose that God formed man from the dust with bodily hands is very childish. "Plant, fowl and animal life aren't perfect...but created in a state of potentiality" |
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Non-Western cultures thoughts on evolution |
Taoism in the 4th century BC China: Humans, nature and the heavens exist in a state of constant transformation. Islamist Philosopher: Animals engage in a struggle for existence. Environmental factors influence organism to develop new characteristics to ensure survival, thus transforming into new species. |
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Essentialism and the Theory of Forms |
- Theory of forms based on idea of essentialism. - Highest form of reality - Every natural object is an imperfect manifestation of the ideal (explains natural variation among species) - compatible with special creation of fixed species - included all conceivable forms (living/nonliving) |
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Allegory of the Cave |
Reality is not directly observed. Objects we see are reflections or shadows of real things. They only mimic real forms |
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Artistotle and The Great Chain of Being |
Artistotle was the earliest natural historian whose written works were preserved. He made empirical observations to inform his ideas, as opposed to plato who relied mostly on logic. Aristotle believed in a chain of beings (dirt at the bottom, animals in middle, God at top). He ranked organisms based on structural complexity and ability to move |
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Immutable Species |
Plato's concept of the ideal form: Immutable essence of all things, nothing directly observed. Natural variation is just accidental imperfection of imitations. |
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Christianity and nature |
Christians believe in special creation and embraced the great chain of being. Had the idea that species must be permanent and unchanging. Change would imply imperfection of the creator. |
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Carl Linnaeus and Classification + Taxonomy |
Swedish Botanist/Zoologist who came up with the formal classification of living organisms that formed the basis of modern taxonomy. |
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How does linnaean taxonomy differ from current taxonomy. |
Linnaeus used relations based on physical similarities, NOT common descent. BUT many of these relationships have proven to be consistent with common descent. |
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G.L.L Buffon and the Enlightenment Era (Mid-Late 18th Century) |
Proposed Earth and life formed according to laws of physics and chemistry - Comet struck the sun, debris cooled to form the Earth - Life made up of same minuscule particles as rocks (now called atoms/molecules) - One set of laws governs attraction of atoms to form larger objects & organisms, another the interaction of these objects with each other. He also said nature in the new world was inferior to Eurasia. |
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James Hutton and the age of Earth (1726-1797) theories |
Plutonism: Volcanoes build mountains, which erode, form layers of rock in the bottom of ocean Uniformitarianism: Natural laws operating today have always/consistently operated Catastrophism: Earth shaped by violent, global events (Hutton opposed this) |
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What were early opinions on fossils? |
In the middle ages, people thought they were geometric impressions in rock, not remnants of life. |
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Steno and fossils |
Fisherman brought Steno a big shark in 1666. He noticed teeth looked like "tongue stones" He suggested they started as teeth and gradually turned to stone after sharks died. |
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The law of superposition |
If stones shaped like tongues/seashells were actually fossilized ocean animals, why were they found on mountain tops. Steno argued mountains were once covered with oceans, animals fell to the bottom when they died, then covered with sediments. New stuff falls on top of old stuff, so bottom layers are older than the top. |
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William Smith and fossil layers |
Smith discovered different layers contained distinct fossils. He matched fossils across different regions of Britain to create the first geologic map. |
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Mary Anning |
Mary Anning (1799-1847) discovered several species of extinct animals, including some dinosaurs. No formal education, but helped her family collect fossils to sell to collectors. She knew more about fossils than men who bought them, but men published them. Discovered pterosaur |
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George Cuvier |
Established the fields of paleontology and comparative anatomy. Examined fossils of elephant-like bones & teeth from Siberia and North America. He concluded they came from species that no longer roamed the Earth. He established extinction as accepted scientific fact |
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What didn't Cuvier accept? |
The idea that organisms changed over time. He asserted that new fossil forms appear abruptly in the rock record and then disappear (catastrophism). Pointed to mummified cats and humans as examples of fixed species. |
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Striving to Evolve + Lamarck (1744-1829) |
Each species is spontaneously generated from non-living matter at the bottom of the chain of being. "Nervous Fluid" causes each species to progress up the chain. Assumed organisms were guaranteed to evolve into a more complex form. Organs/structures that are exercised attract more "nervous fluid" causing those organs to become more developed (Giraffe evolved long neck due to stretching). The concept doesn't invoke common ancestry. Inheritance of acquired characteristics |
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Charles Darwin (1809-1882) |
Supposed to be doctor, but didn't. Went on 5 year expedition on HMS Beagle to South American coast). |
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Charles Lyell (1797-1875) |
Wrote "Principles of Geology" which was given to Darwin by the captain of their voyage. Lyell popularized Hutton's idea of uniformitarianism. |
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What did Darwin observe? |
He made many geological and biological observations. Saw land raised after an earthquake in Chile (saw as demonstration of uniformitarianism). Inspired his hypothesis of the formation of atols (observed intermediate formation of islands) Also saw variation in finches, tortoises and other animals on Galapagos. |
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Similarity as Variation on an Archetype |
Some early anatomists argued that modification was created. Related species created by making tweaks to an archetype (like how iphones are just moderately tweaked every year). |
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Descent from a common ancestor |
Darwin argued that similarities between were due to common ancestry. Descent from these common ancestors, with modification, explains the origin of new species, with homology describing a particular feature that is shared between two species by common descent. One ancestor existed in the past, different from all it's descendants. |
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Where are similarities most apparent? |
They are most apparent in early development (embryos). |
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Influence from an Economist |
An essay on the principle of Population by Thomas Malthus. Population growth exceeds the ability of Earths resources to sustain it. Growth is eventually checked by famine or disease. |
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4 points to Darwin's Theory of Natural Selection |
1. Resource limitation prevents populations from realizing their potential to grow exponentially. 2. Variation among individuals exists in populations 3. Resource limitation + variation = differential survival 4. Heritability of variation causes populations to change over time |
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On the Origin of Species |
Darwin sat on his theory for years, communicating ideas to friends. Lyell urged him to publish the book because Wallace seemed to have similar ideas. Darwin began writing, anticipating criticism. Wallace and Darwin published a paper about natural selection together in 1858. Decided on a presentation at Linnaean Society giving both men credit. Darwin continued working on his big book and published it in 1859. It was widely popular but reactions were mixed. Richard Own agreed evolution occurred, but dismissed Darwin as being overly simplistic. Thomas Huxley vigorously agreed with him. |
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Problem's With Darwin's Theory |
Lacked a mechanism for inheritance and he recognized this as a problem. BUT only in a sense that it presented a challenge in presenting his theory completely. Darwin was convinced offspring inherited characteristics from parents, but didn't know how it happened. |
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Predictive Power of Darwin's Theory |
Much of evolution is a very slow process that is impossible to observe directly. BUT some isn't (Bacteria/Viruses reproduce quickly, new vaccine every year which eventually lead to antibiotic resistance). We can then extrapolate what we learn to more long-term processes of evolution. Macroevolution is microevolution writ large. |
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Haeckel (1834-1919) |
Did art to demonstrate Darwins Theory |
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Key Points |
1. Evo is consistent with known genetics 2. Evo is gradual 3. N.S is the main mechanism of change 4. Genetic Drift (random) is minimal 5. Think in terms of pop not individuals 6. Extrapolation from micro to macro |
