Assessment #2 next week
o Watch OWL for details
o Lecture 9-15
Hardy-Weinberg also assumes random mating with respect to genotype
o But mating is often non-random
inbreeding or inbreeding avoidance
assortative or disassortative mating
Non-random mating and evolution?
o If a population begins mating assortatively for a certain trait, but
all genotypes have the same fitness, what will happen?
2 alleles, 3 genotypes (AA, Aa, aa)
each genotype mates assortatively
250 AA, 500 Aa, 250 aa (mate with organism that have the
population of AA and aa will stay the same,
but the population of Aa will decrease over time because
they'll create 125 AA, 250 Aa, and 125 aa
so as it goes on, the heterozygous population will decrease
Why Evolution is True
"Humans evolved from earlier species of animals"
Evolution as a fact and a theory
o what do scientists mean by "a theory"?
o what do we mean by "true"?
o what is the theory of evolution
o and what empirical evidence supports this theory?
Evolution is "only a theory"...
o "an assumption based on limited knowledge... a conjecture"
(found in dictionaries)
o "a coherent set of testable hypotheses that attempt to explain
facts about the natural world" (scientific way)
theory has to be testable
one can show the theory to be wrong (if theory is false, we
can show its false)
Atomic theory of matter
Germ theory of infectious disease
What do scientists mean when we say that something is "true"?
o "an assertion for which there is so much evidence that it would be
perverse to deny it|" - SJ Gould
o Theories "graduate" to fact-hood after repeated testing fails to
o Assertions that cannot possibly be falsified are not sci