BIOL 117 FINAL UPDATED ACTUAL HIGH-YIELD
CELL BIOLOGY AND GENETICS SUMMARY
2026
◉ Biological species concept- defining a species
Answer:
◉ prezygotic isolating mechanisms
Answer: when individuals of different species are prevented from
mating
Temporal-different mating times
Habitats
Behavioral, i.e. different mating calls
Mechanical-structurally incompatible
genetic-gametes wont fuse
◉ Postzygotic isolating mechanism
Answer: individuals of different species mate but the hybrid
produced has low fitness and may not survive or produce offspring
inviability-embryos may not develop properly
fertility-hybrids cannot produce offspring
,i.e. mules from horse and donkey
◉ Allopatric speciation
Answer: speciation due to geographic separation, when a population
becomes isolated by a physical barrier mutations arise and are
reproductively isolated if the species come into contact i.e. squirrels
on either side of grand canyon
◉ Vicariance
Answer: the physical separation of a species
◉ vicariance vs dispersal
Answer: Vicariance -> physical barrier
dispersal -> migration
◉ Sympatric speciation
Answer: speciation in same geographic location due to niches that
need to filled or behavioral changes that exacerbated into two
species over time i.e. flies in hawthorne berries and apples which
eventually led flies' birth cycles to align with fruit cycles
◉ Autopolyploidy in plants
Answer:
, ◉ Allopolyploidy in plants
Answer:
◉ Isolated populations coming into contact results in
Answer: if prezygotic barriers do not have an effect, populations
could breed
Reinforcement, hybrid zones, and speciation by hybridization could
also occur
◉ Reinforcement
Answer: offspring have lower fitness reinforcing genetic isolation,
occurs more in allopatric species
◉ Hybrid zones
Answer: intermediate between two species (parent population)
which can lead to extinction or a new species based on the fitness of
the hybrid
◉ Speciation by hybridization
Answer: creation of a third species with alleles from both parents
◉ Hardy-Weinberg Principle
CELL BIOLOGY AND GENETICS SUMMARY
2026
◉ Biological species concept- defining a species
Answer:
◉ prezygotic isolating mechanisms
Answer: when individuals of different species are prevented from
mating
Temporal-different mating times
Habitats
Behavioral, i.e. different mating calls
Mechanical-structurally incompatible
genetic-gametes wont fuse
◉ Postzygotic isolating mechanism
Answer: individuals of different species mate but the hybrid
produced has low fitness and may not survive or produce offspring
inviability-embryos may not develop properly
fertility-hybrids cannot produce offspring
,i.e. mules from horse and donkey
◉ Allopatric speciation
Answer: speciation due to geographic separation, when a population
becomes isolated by a physical barrier mutations arise and are
reproductively isolated if the species come into contact i.e. squirrels
on either side of grand canyon
◉ Vicariance
Answer: the physical separation of a species
◉ vicariance vs dispersal
Answer: Vicariance -> physical barrier
dispersal -> migration
◉ Sympatric speciation
Answer: speciation in same geographic location due to niches that
need to filled or behavioral changes that exacerbated into two
species over time i.e. flies in hawthorne berries and apples which
eventually led flies' birth cycles to align with fruit cycles
◉ Autopolyploidy in plants
Answer:
, ◉ Allopolyploidy in plants
Answer:
◉ Isolated populations coming into contact results in
Answer: if prezygotic barriers do not have an effect, populations
could breed
Reinforcement, hybrid zones, and speciation by hybridization could
also occur
◉ Reinforcement
Answer: offspring have lower fitness reinforcing genetic isolation,
occurs more in allopatric species
◉ Hybrid zones
Answer: intermediate between two species (parent population)
which can lead to extinction or a new species based on the fitness of
the hybrid
◉ Speciation by hybridization
Answer: creation of a third species with alleles from both parents
◉ Hardy-Weinberg Principle
