BIOLOGY 101 EXAM 4 2026 POPULATION
DYNAMICS AND COMMUNITY
INTERACTIONS REVIEW PAPER ANSWERS
COMPLETE LEARNING PACK
◉ A geneticist studied a grass population growing in an area of
erratic rainfall and found that plants with alleles for curled leaves
reproduce better and dryers, and plants with alleles for flat leaves
produced better in what years. This situation would
Answer: Preserve the variability in the grass population (both type
survive in approximately equal numbers over several years)
◉ birds with average sized wings survive severe storms more
successfully than birds in the same population that have longer or
shorter wings. This illustrates
Answer: Stabilizing selection
◉ a population of squirrels is preyed on by small hawks the smaller
squirrels can escape into burrows the larger squirrels can fight off
the Hawks. After several generations, the squirrels in the area tend
to be very small or very large. What process is responsible for this
outcome?
Answer: Disruptive selection
, ◉ Which of the following is an example of stabilizing selection?
Answer: The birth weight at which newborn humans are most likely
to survive and the average weight is about the same.
◉ Three species of North American frogs, leopard frogs, green frogs,
and wood frogs, all mate in the same ponds, but they pair off
correctly because they have different mating calls. This is a specific
example of a. Barrier called. .
Answer: Prezygotic barrier..... Behavioral isolation
◉ If two North American frog species, bullfrogs and green frogs
mate The offspring die early in embryonic development. This is an
example of
Answer: reduced hybrid viability
◉ two species of water lilies in the same pond do not interbreed
because one blooms at night and the other blooms during the day.
The reproductive barrier between them is an example of
Answer: Temporal isolation
◉ What is the name for the process by which species may be formed
if the population becomes separated by a geographic barrier?
Answer: Allopatric speciation or geographic isolation
DYNAMICS AND COMMUNITY
INTERACTIONS REVIEW PAPER ANSWERS
COMPLETE LEARNING PACK
◉ A geneticist studied a grass population growing in an area of
erratic rainfall and found that plants with alleles for curled leaves
reproduce better and dryers, and plants with alleles for flat leaves
produced better in what years. This situation would
Answer: Preserve the variability in the grass population (both type
survive in approximately equal numbers over several years)
◉ birds with average sized wings survive severe storms more
successfully than birds in the same population that have longer or
shorter wings. This illustrates
Answer: Stabilizing selection
◉ a population of squirrels is preyed on by small hawks the smaller
squirrels can escape into burrows the larger squirrels can fight off
the Hawks. After several generations, the squirrels in the area tend
to be very small or very large. What process is responsible for this
outcome?
Answer: Disruptive selection
, ◉ Which of the following is an example of stabilizing selection?
Answer: The birth weight at which newborn humans are most likely
to survive and the average weight is about the same.
◉ Three species of North American frogs, leopard frogs, green frogs,
and wood frogs, all mate in the same ponds, but they pair off
correctly because they have different mating calls. This is a specific
example of a. Barrier called. .
Answer: Prezygotic barrier..... Behavioral isolation
◉ If two North American frog species, bullfrogs and green frogs
mate The offspring die early in embryonic development. This is an
example of
Answer: reduced hybrid viability
◉ two species of water lilies in the same pond do not interbreed
because one blooms at night and the other blooms during the day.
The reproductive barrier between them is an example of
Answer: Temporal isolation
◉ What is the name for the process by which species may be formed
if the population becomes separated by a geographic barrier?
Answer: Allopatric speciation or geographic isolation
