Lecture 8- Evolutionary Mechanisms Flashcards
polygenic inheritance
multiple genes independently affect a single character (Ex. Height)
Pleiotropy
the ability of a single gene to have multiple effects
Genetic drift
chance events cause allele frequencies to fluctuate unpredictably
genetic drift is caused by
chance events associated with survival and reproduction
in genetic drift, the smaller the sample:
the greater the chance of random deviation from a predicted result
difference between natural selection and genetic drift is
natural selection is based on optimal phenotypes and evolution is carried out based on that while genetic drift is random
can genetic drift be predicted?
no, it’s random
founder effect
when a few individuals become isolated from the larger population, the new population’s gene pool will differ from the source population
Bottleneck effect
sudden change in the environment drastically reduces the size of the population
Are bottleneck effect and founder effect examples of genetic drift?
no, but they can RESULT in genetic drift
Genetic drift can limit the ability of a population to
adapt
adaptation definition
a feature that arose and was favored by natural selection for its current function
Gene flow
the movement of alleles among populations
alleles can be transferred through the movement of
fertile individuals or gametes
gene flow tends to reduce
variation among populations over time
