Biology 112 TAMU Exam 1- Lee
Questions with Actual Answers.
prezygotic barrier - Answer blocks fertilization from occurring
-impeding different species from mating
-prevents successful completion of mating
-hinders fertilization
forms of prezygotic barrier - Answer -habitat isolation
-temporal isolation
-behavioral isolation
-mechanical isolation
-gametic isolation
habitat isolation - Answer two species occupy different habitats and encounter each other
rarely, or never
temporal isolation - Answer species that breed at different seasons, years, or times of the day
behavioral isolation - Answer courtship rituals and behaviors unique to a species that are
effective mating barriers
mechanical isolation - Answer morphological (structural) differences can prevent successful
completion of mating
ex: left and right handed snails are physically incapable of mating
gametic isolation - Answer sperm of one species may not be able to fertilize the eggs of
another species
ex: species specific bindin proteins on sperm have to hit specific receptors on the cover of an
egg to fertilize
post-zygotic barriers - Answer prevent the hybrid zygote from developing into a viable, fertile
adult; hybrids are extant for short periods of time
,-fertilization, gestation, and organism is born
forms of post-zygotic barriers - Answer -reduced hybrid viability
-reduced hybrid fertility
-hybrid breakdown
hybrid - Answer offspring of crosses between different species
reduced hybrid viability - Answer genes of different parent species may impair the hybrid's
development and survival
reduced hybrid fertility - Answer even if hybrids are vigorous, they may be sterile
ex: mule
hybrid breakdown - Answer some first-generation hybrids are fertile, but offspring of the next
generation are feeble or sterile
ex: certain cotton species; first generation is fertile and offspring die or become defective
speciation - Answer the formation of two new species from one original one
-allopatric specitation
-sympatric speciation
biological species concept - Answer -group that can interbreed
-they do interbreed
-choose not to interbreed with other "groups"
-have viable offspring
species as groups of interbreeding populations that are reproductively isolated
allopatric speciation - Answer involves geographic isolation
-the greater a barrier subdivides a region, the greater the degree to which speciation will occur
, allopatric speciation pt.2 - Answer -dispersal
-vicarience
-adaptive radiation
dispersal - Answer (allopatric speciation) when a few member of a species move to a new
geographical area
vicariance - Answer (allopatric speciation) when a natural barrier arises to physically divide
organisms
ex: river splitting
adaptive radiation - Answer speciation when one species radiates to form other species
ex: honeycreeper bird and varying types of beaks
sympatric speciation - Answer occurs in the same geographical area
sympatric speciation pt 2. - Answer chromosomal errors in cell division
-aneuploidy
-autoploidy
-alloploidy
reproductive isolation
-prezygotic vs postzygotic barriers
aneuploidy - Answer having an extra or missing chromosome
ex: down syndrome
autoploidy - Answer more than two chromosome sets derived from a single species
alloploidy - Answer multiple sets of chromosomes derived from different species
Questions with Actual Answers.
prezygotic barrier - Answer blocks fertilization from occurring
-impeding different species from mating
-prevents successful completion of mating
-hinders fertilization
forms of prezygotic barrier - Answer -habitat isolation
-temporal isolation
-behavioral isolation
-mechanical isolation
-gametic isolation
habitat isolation - Answer two species occupy different habitats and encounter each other
rarely, or never
temporal isolation - Answer species that breed at different seasons, years, or times of the day
behavioral isolation - Answer courtship rituals and behaviors unique to a species that are
effective mating barriers
mechanical isolation - Answer morphological (structural) differences can prevent successful
completion of mating
ex: left and right handed snails are physically incapable of mating
gametic isolation - Answer sperm of one species may not be able to fertilize the eggs of
another species
ex: species specific bindin proteins on sperm have to hit specific receptors on the cover of an
egg to fertilize
post-zygotic barriers - Answer prevent the hybrid zygote from developing into a viable, fertile
adult; hybrids are extant for short periods of time
,-fertilization, gestation, and organism is born
forms of post-zygotic barriers - Answer -reduced hybrid viability
-reduced hybrid fertility
-hybrid breakdown
hybrid - Answer offspring of crosses between different species
reduced hybrid viability - Answer genes of different parent species may impair the hybrid's
development and survival
reduced hybrid fertility - Answer even if hybrids are vigorous, they may be sterile
ex: mule
hybrid breakdown - Answer some first-generation hybrids are fertile, but offspring of the next
generation are feeble or sterile
ex: certain cotton species; first generation is fertile and offspring die or become defective
speciation - Answer the formation of two new species from one original one
-allopatric specitation
-sympatric speciation
biological species concept - Answer -group that can interbreed
-they do interbreed
-choose not to interbreed with other "groups"
-have viable offspring
species as groups of interbreeding populations that are reproductively isolated
allopatric speciation - Answer involves geographic isolation
-the greater a barrier subdivides a region, the greater the degree to which speciation will occur
, allopatric speciation pt.2 - Answer -dispersal
-vicarience
-adaptive radiation
dispersal - Answer (allopatric speciation) when a few member of a species move to a new
geographical area
vicariance - Answer (allopatric speciation) when a natural barrier arises to physically divide
organisms
ex: river splitting
adaptive radiation - Answer speciation when one species radiates to form other species
ex: honeycreeper bird and varying types of beaks
sympatric speciation - Answer occurs in the same geographical area
sympatric speciation pt 2. - Answer chromosomal errors in cell division
-aneuploidy
-autoploidy
-alloploidy
reproductive isolation
-prezygotic vs postzygotic barriers
aneuploidy - Answer having an extra or missing chromosome
ex: down syndrome
autoploidy - Answer more than two chromosome sets derived from a single species
alloploidy - Answer multiple sets of chromosomes derived from different species
