Forces of Evolutionary Change Part 1 Flashcards
What is evolution
change over time; ‘descent with modification’
where does evolution occur?
in a population - individuals don’t evolve, the population changes over multiple generations
What are evolutionary changes based on?
the gene pool’s allele frequencies
allele frequencies
number of copies of that allele divided by the total number of alleles in the population; determines characteristics for a population - why populations look different
What ship did Charles Darwin sail on and how long?
the HMS Beagle and a 5 year voyage
Charles Darwin was a
naturalist
What book did he write and when?
1859: On the Origin of Species
Notes on finches
ornithologist: ate a variety of seeds; different beak types; 14 different types of finches; shared characteristics with those from the mainland
Wrote notes about Galapagos tortoise’s…
neck length
“Descent with Modification”
gradual change from an ancestor
Thomas Malthus
wrote Essay on the Principle of Population - Food availability, disease and war limit population size…
Darwin’s analysis on Malthus’ findings
this should be the same for all species right?
natural selection
occurs when environmental factors cause the differential reproductive success of individuals with particular genotypes
artificial selection
choosing of desired traits
Modern Evolutionary Synthesis
Genetic mutations create heritable variation and this variation is what natural selection acts on (acts on the phenotype)
Theory of Evolution by natural selection
all organisms use the same genetic code, the same chemical reactions and many of the same proteins - homologous structures and embryonic development similarities; descent from a common ancestor
Adaptations
Features that provide a selective advantage and improve survival and reproduction; it is heritable and becomes more common with each generation
Natural selection is not a
random process
Natural selection…
eliminates phenotypes by ‘weeding out’ certain phenotypes and as environment changes, so must those in it; those who change change to have the ‘best’ phenotype
natural selection does not have a goal. why?
no way of ‘telling’ DNA to mutate; no way of knowing future; if you don’t have a certain allele for a change, you may go extinct
survival of the fittest
fitness is one’s reproductive contribution to the next generation; survival is not enough… it’s how many alleles you can pass on.
