BIO 212 Exam 4 Questions with Correct Answers Latest Update 2025/2026
Reciprocal evolutionary change between interacting species, driven by natural selection. -
Answers Coevolution
A relationship between species in which both species benefit. - Answers Mutualism
Nutritious, lipid-rich appendages on seeds that attract ants. - Answers Elaiosomes
Ants collect seeds that have elaiosomes, eat the elaiosomes, and plants have their seeds
dispersed. - Answers Seed Dispersal
Some wrass species clean mouths of moray eels, providing food for wrass and removing debris
for eels. - Answers Cleaners
Joshua Trees are only pollinated by yucca moths, which feed on Joshua tree seeds. - Answers
Pollinators
A relationship in which one species benefits and the other species is harmed. - Answers
Antagonism
Example: Black bear (Ursus americanus) with a salmon. - Answers Predator/prey
Example: Desert cottontail (Sylvilagus audubonii) eating vegetation. - Answers Herbivore/plant
Orchids mimic female wasps to attract male wasps for pollen transfer. - Answers Deceptive
pollination
Example: Brown-headed cowbirds lay eggs in nests of other birds. - Answers Parasite/host
Some hosts incubate cowbird eggs and feed cowbird young; behaviors can change based on
frequency of brood parasitism. - Answers Brood Parasitism
A relationship between species in which one species benefits and the other species neither
benefits nor is harmed. - Answers Commensalism
Benefits by being transported to new feeding grounds; nudibranch is not harmed. - Answers
Emperor shrimp
Both species are harmed because they are using the same limited resource (food, space, mates,
etc.). - Answers Competition
Two species of finches competing for the same seed size. - Answers Example of Competition
One species is harmed, while the other is unaffected. - Answers Amensalism
A plant releasing chemicals that kill nearby seedlings but gaining no direct benefit. - Answers
Example of Amensalism
, Both species have no significant effect on one another. - Answers Neutralism
An evolutionary outcome caused by competition, leading to traits diverging in species. -
Answers Character displacement
Many species evolve from a common ancestor and specialize on different niches. - Answers
Adaptive radiation
The classification of an interspecific interaction (mutualism, commensalism, antagonism, etc.)
is not fixed and can change over time as more information is gathered. - Answers Interspecific
interaction
Environmental changes can shift costs and benefits, altering the interaction type. - Answers
Environmental changes
Parasite-host coevolution occurs through a repeating cycle of adaptation and counter-
adaptation, often described as a coevolutionary arms race or cyclic (Red Queen) dynamics. -
Answers Parasite-host coevolution
When a parasite infects a host population, it reduces host fitness, creating strong selection for
host individuals that carry defensive traits. - Answers Host fitness
These mutations spread, increasing the frequency of resistant genotypes. - Answers Beneficial
host mutations
Describes the strength of selection that occurs in two species due to their interactions with one
another. - Answers Reciprocal selection
The selective value of a trait depends on its abundance. - Answers Frequency dependent
selection
Fitness decreases when a trait is common; example: brood parasites. - Answers Negative
frequency dependent selection
Fitness increases when a trait is common; example: Mullerian mimicry (bees/wasps). - Answers
Positive frequency dependent selection
Coevolution requires genetic variation on which selection can act. - Answers Genetic variation
Populations vary in the strength of reciprocal selection across their geographic range. - Answers
Geographic variation in coevolution
When traits are costly, they often go away when selective pressures are removed. - Answers
Costs of traits
Success of parasitoid wasp was heritable when tested on clonal aphids, had genetic variation
among lines. - Answers Example of parasitoid wasps
Reciprocal evolutionary change between interacting species, driven by natural selection. -
Answers Coevolution
A relationship between species in which both species benefit. - Answers Mutualism
Nutritious, lipid-rich appendages on seeds that attract ants. - Answers Elaiosomes
Ants collect seeds that have elaiosomes, eat the elaiosomes, and plants have their seeds
dispersed. - Answers Seed Dispersal
Some wrass species clean mouths of moray eels, providing food for wrass and removing debris
for eels. - Answers Cleaners
Joshua Trees are only pollinated by yucca moths, which feed on Joshua tree seeds. - Answers
Pollinators
A relationship in which one species benefits and the other species is harmed. - Answers
Antagonism
Example: Black bear (Ursus americanus) with a salmon. - Answers Predator/prey
Example: Desert cottontail (Sylvilagus audubonii) eating vegetation. - Answers Herbivore/plant
Orchids mimic female wasps to attract male wasps for pollen transfer. - Answers Deceptive
pollination
Example: Brown-headed cowbirds lay eggs in nests of other birds. - Answers Parasite/host
Some hosts incubate cowbird eggs and feed cowbird young; behaviors can change based on
frequency of brood parasitism. - Answers Brood Parasitism
A relationship between species in which one species benefits and the other species neither
benefits nor is harmed. - Answers Commensalism
Benefits by being transported to new feeding grounds; nudibranch is not harmed. - Answers
Emperor shrimp
Both species are harmed because they are using the same limited resource (food, space, mates,
etc.). - Answers Competition
Two species of finches competing for the same seed size. - Answers Example of Competition
One species is harmed, while the other is unaffected. - Answers Amensalism
A plant releasing chemicals that kill nearby seedlings but gaining no direct benefit. - Answers
Example of Amensalism
, Both species have no significant effect on one another. - Answers Neutralism
An evolutionary outcome caused by competition, leading to traits diverging in species. -
Answers Character displacement
Many species evolve from a common ancestor and specialize on different niches. - Answers
Adaptive radiation
The classification of an interspecific interaction (mutualism, commensalism, antagonism, etc.)
is not fixed and can change over time as more information is gathered. - Answers Interspecific
interaction
Environmental changes can shift costs and benefits, altering the interaction type. - Answers
Environmental changes
Parasite-host coevolution occurs through a repeating cycle of adaptation and counter-
adaptation, often described as a coevolutionary arms race or cyclic (Red Queen) dynamics. -
Answers Parasite-host coevolution
When a parasite infects a host population, it reduces host fitness, creating strong selection for
host individuals that carry defensive traits. - Answers Host fitness
These mutations spread, increasing the frequency of resistant genotypes. - Answers Beneficial
host mutations
Describes the strength of selection that occurs in two species due to their interactions with one
another. - Answers Reciprocal selection
The selective value of a trait depends on its abundance. - Answers Frequency dependent
selection
Fitness decreases when a trait is common; example: brood parasites. - Answers Negative
frequency dependent selection
Fitness increases when a trait is common; example: Mullerian mimicry (bees/wasps). - Answers
Positive frequency dependent selection
Coevolution requires genetic variation on which selection can act. - Answers Genetic variation
Populations vary in the strength of reciprocal selection across their geographic range. - Answers
Geographic variation in coevolution
When traits are costly, they often go away when selective pressures are removed. - Answers
Costs of traits
Success of parasitoid wasp was heritable when tested on clonal aphids, had genetic variation
among lines. - Answers Example of parasitoid wasps
