Descent With Modification Lecture 18 Flashcards
what does natural selection result in
adaptive evolution
before Darwin, what did Aristotle think
– Viewed species as fixed and unchanging
– Life could be arranged on a scale of increasing complexity
* “scala naturale”
what did the old testament say regarding this
Holds that species were individually designed by God
what did Carolus Linnaeus say regarding this, who was she ?
– Was a founder of taxonomy,
– Did not attribute resemblances among species to evolutionary kinship,
* Attributed similarities rather to the pattern of their creation
what helped lay the groudwork for Darwin’s ideas
the study of fossils (paleontology)
where are remains or traces of the organisms usually found
- sedamentary rocks
- in layers (strata)
what do fossils show
succession of organisms have populated earth through time
what did cuvier note about stratas
the older the strata, the more dissimilar the fossils from modern life
what is catastrophism theory
speculating that boundaries between strata were due to local floods or droughts that destroyed the species present.
what did JB Lamarck propose before Darwin
Organisms pass traits to offspring through use and disuse
* parts of the body used extensively become stranger & larger, while those not used deteriorate
—- change in environment changes behavior
according to Lamarck, how did organisms pass traits to offsprings
disuse
what did Hutton propose before Darwin
proposed a theory of gradualism
– Gradualism: profound change can take place through the cumulative effect of slow but continuous processes
what did Lyell propose before Darwin
perceived that changes in Earth’s surface can result from slow continuous actions still operating today
– i.e. valleys formed by rivers wearing away at rocks
what did Darwin develop his theory on
i) Malthus’ essay: Struggle for existence
ii) Lyell’s Principles of Geology
iii) Principles of artificial selection also influenced Darwin’s theories
iv) His data (what he saw in the Galapagos)
explain how struggle for existence helped Darwin
Thomas Robert Malthus
* Population growth not always desirable
* Conflict between population growth and food supply generates famine, disease, war, which inevitably break population growth
explain how Lyell’s principle helped Darwin
- he experienced geologic change (earthquakes, rocks thrust upwards, earth not static)
- Reinforced Darwin’s acceptance of Lyell’s
ideas - doubt about the traditional view of a young and
static Earth.
explain how artificial selection helped Darwin
Humans have modified domesticated plants and animals in just a few generations by selecting individuals with the desired traits for breeding.
therefore, If artificial selection can achieve large change in a relatively short period of time, Darwin reasoned that natural selection should be capable of modification over thousands of generations.
what is Darwin’s data from the Galapagos
- voyage was the basis of the theory of evolution
- Darwin observed various adaptations of plants and animals that inhabited the many diverse environments
Compared animals on islands (ex: Galapagos) with those of mainland. - Impressed by similarities and ALSO distinct differences
how long was Darwin’s exploration
5 years
what did Darwin hypothesis during his voyage
that the islands had been colonized by plants and animals from the mainland that had subsequently diversified on the different islands.
when did Darwin write long essay on origin of species and naturel selection
1840s (relunctant to publish)
When did Alfred Russel Wallace (1823–1913), a young naturalist, send Darwin a manuscript containing a theory of natural selection essentially identical to Darwin’s
1858
when did Darwin publish the origin of species
1859
check how naturel selection works in slides **
