BIOL 290 Lecture 5: Other Factors that Effect the Population
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Published on 21 Sep 2018
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Other Factors that Effect the Population
Friday, September 21, 2018
9:14 AM
• Recombination:
• Pairing of homologous chromosomes during meiosis
• Humans have 23 pairs of chromosomes, and humans have 46 all together
• People will use the "proof" that we have different numbers of chromosomes than other primates,
we can't be related to them
• Telomeres & centromeres; telomeres are protective caps, and centromeres are in the middle; they
fuse together at the telomeres; and some scientists say that’s why we have 46, while other
primates have 48
• Random Genetic Drift
• Random subsampling of populations
• Ex: brown rabbits reproduce faster than white rabbits, in the second generation there will be
more brown, third all brown
• Random event; wipeout, natural disaster, etc.,
• Gene Flow:
• Movement of alleles, genes, gametes between populations
• Happens through immigration/emigration, and migration
• Hybridization: two species interbreed and give rise to a new hybrid species with different genetic
information
• Two species interbred and gave rise to a new species
• Populations are units of evolution
o A population is a group of individuals of the SAME species living in the SAME place at the
SAME time
o A species: made up of a group of populations whose individuals have the potential to
interbreed and produce fertile offspring
• Individuals do not evolve
• Evolution is a process; that has many mechanisms
o Evolution by natural selection is a genetic change in a population that occurs between, or
over the course of generations
• Evolution acts on existing heritable (genetic) variation
• Involves changes in the frequency of particular traits due to differential success
among individuals
• Natural selection does not cause mutation; variations are ALREADY there; it just
selects the best variation
1. Natural selection involves individuals trying to adapt to current environmental conditions: FALSE
2. What is evolution?: Process
3. How can we depict evolution: Evolution is a gradual branching of lineages