evolution lecture 1 Flashcards
what was Darwin’s book in 1859 called?
the origin of species
what were the thoughts surrounding biology, before evolution?
- species were unchanging
- ladder of increasing perplexity
- more complex, the closer to divine/ god
Linneaus biological classification 1758
hiearchy of nested sets
- groups within groups
what is palentology based on?
Fossils
what did lamark see because of fossils?
progression in species
- suggested forms come into being by being modifications of previous forms
the two parts to Lamarks idea?
1) pattern
- each of the many seperate lineages of independant
origin strive to perfection/ complexity
2) Process/ mechanism
- “use and disuse of parts”
what is “larmarkism”?
the inheritance of acquired characters
In general, what were Lamark’s ideas?
- a poor fit to biological classification
- a meachnism that was not well supported
- however, it explains the variation among species
What did Darwin do before all this biological ideas and his book?
go to medical school
he was a medical school drop out
what were Darwins two main ideas?
1) the PATTERN of evolution
2) the PROCESS of evolution
what was darwins pattern evolution idea?
living things united in a single branching tree of relationships
- new lineages constatnly being created by existing ones being splitted in two
- “descent with modification” Species A and B are similar because they share common ancestor
- but A and B differ because of the changes after divergence from their last common ancestor
what was Darwin’s process of evolution idea?
- evolution happens mostly because of natural selection
What are the ingredients to natural selection?
- Heritable variation
- Excess production
- Differential success
natrual selectino thought heritable excess was differential success
KEY POINT: individuals of a species belong to populations
what is heritable variation?
- individuals are born with many varying traits
- many traits can be passed on to offspring from parents
what is excess production?
- in any population, more offspring are produced than needed
what is differential success?
-excess production leads to competition
- because of their differing traits, individuals will have varying levels of success
- some individuals will produce more offspring because of their traits being an advantage
This is the concept of FITNESS
- favourable traits increase in frequency in the population
- evolution
What does natural selection act on?
existing variation (it does not generate variation)
how does variation happen?
mutations in genome
what showed the plausibility of natural selection?
artificial selection
what does natural selection over time result in
adaptation!
- adaptive evolution
