©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
EEB 184 Units 5 & 6 Exam Questions And
Answers (Guaranteed A+)
Define "developmental plasticity" and describe two examples of instances of developmental
plasticity in animals - answer✔- adjustment of gene expression to produce a phenotype in
utero that will likely be most appropriate for postnatal environment
- bicyclus anyana and spea vs scaphipous spadefoot toads
Explain how individuals in a population can exhibit different developmental responses to the
same environmental stimuli - answer✔preexisting phenotypic plasticity in ancestral lineage
could lead to certain genotypes within a community of individuals to eventually branch off into
its own species, or genetic accommodation
Explain how developmental plasticity can evolve using the terms variation, developmental
process, gene, population, heritable environment, and natural selection. - answer✔
Some scientists have argued that developmental plasticity inhibits evolutionary change, while
others have argued that developmental plasticity facilitates evolutionary change. Defend one of
these arguments. - answer✔Developmental plasticity facilitates evo change as seen in spea vs
scaphiopus toads that were derived from the same common ancestor.
plasticity - answer✔- refers to the property by which the same genotype produces distinct
phenotypes depending on the environmental conditions under which development takes place
- plasticity itself is an heritable trait that is under selection and can evolve but on the other
hand plasticity has been proposed to impact adaptive evolution
Bicyclus anyana - answer✔- wet vs dry season
- Eyespots help divert attention of predators
- Helps it survive attacks and incidentally lay more eggs
- Preying mantis would attack butterflies with eyespots more frequently but would be less
successful in their attack (bc they aim for eyespot not body)
- temperature is the environmental cue that drives phenotypic change in butterfly wing
-ecdysteroid is the factor that regulates the eyespot size (incr before eyespot when temp incr)
1|Page
, ©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
- change ventrally, no change dorsally
inductive environment - answer✔genotypes
selective environment - answer✔alternative phenotypes
ecdysone - answer✔the major steroid hormone in insects and plays essential roles in
coordinating developmental transitions such as larval molting and metamorphosis through its
active metabolite 20E
enabling mutation - answer✔refers to a genetic alteration conferring environmental sensitivity
to a phenotype that was originally not plastic. this allows the expression of plasticity which can
thereafter be shaped by selection
genetic accommodation - answer✔refers to the process by which selection shapes the
properties and/or magnitude of a plastic response
genetic assimilation - answer✔refers to the process of genetic accommodation by which there
is the fixation of what were previously induced phenotypes
tobacco hornworms - answer✔only green
tomato hornworms - answer✔green when >28C, black otherwise
black mutant tobacco hornworms - answer✔show green when heat shocked
abdomina and thoracic ligations - answer✔- ligation behind the first abdominal segment, the
anterior compartment of larvae from the polyphenic line changed color upon heat shock, but
the posterior did not. monophenic line remained black
- ligation placed behind the neck, no color change response to heat shock was observed in
either line
corpora allata - answer✔produces JH
prothoracic gland - answer✔produces ecdysone
sensitivity to JH - answer✔monophenic lines differ in sensitivity to JH
Buying time hypothesis - answer✔suggests that when a colonizing a new habitat or facing
environmental perturbation, a "plastic population" can first adjust to the new conditions by
expressing distinct plastic phenotypes and thereby persist enough time for new mutations to
happen and fuel adaptive evolution
Plasticity-first hypothesis - answer✔proposes that plasticity can initiate and accelerate the rate
of phenotypic change in that plastic adaptive phenotypes can emerge earlier and faster than
phenotypic changes due to genetic mutation
2|Page
ALL RIGHTS RESERVED.
EEB 184 Units 5 & 6 Exam Questions And
Answers (Guaranteed A+)
Define "developmental plasticity" and describe two examples of instances of developmental
plasticity in animals - answer✔- adjustment of gene expression to produce a phenotype in
utero that will likely be most appropriate for postnatal environment
- bicyclus anyana and spea vs scaphipous spadefoot toads
Explain how individuals in a population can exhibit different developmental responses to the
same environmental stimuli - answer✔preexisting phenotypic plasticity in ancestral lineage
could lead to certain genotypes within a community of individuals to eventually branch off into
its own species, or genetic accommodation
Explain how developmental plasticity can evolve using the terms variation, developmental
process, gene, population, heritable environment, and natural selection. - answer✔
Some scientists have argued that developmental plasticity inhibits evolutionary change, while
others have argued that developmental plasticity facilitates evolutionary change. Defend one of
these arguments. - answer✔Developmental plasticity facilitates evo change as seen in spea vs
scaphiopus toads that were derived from the same common ancestor.
plasticity - answer✔- refers to the property by which the same genotype produces distinct
phenotypes depending on the environmental conditions under which development takes place
- plasticity itself is an heritable trait that is under selection and can evolve but on the other
hand plasticity has been proposed to impact adaptive evolution
Bicyclus anyana - answer✔- wet vs dry season
- Eyespots help divert attention of predators
- Helps it survive attacks and incidentally lay more eggs
- Preying mantis would attack butterflies with eyespots more frequently but would be less
successful in their attack (bc they aim for eyespot not body)
- temperature is the environmental cue that drives phenotypic change in butterfly wing
-ecdysteroid is the factor that regulates the eyespot size (incr before eyespot when temp incr)
1|Page
, ©FYNDLAY EXAM SOLUTIONS 2024/2025
ALL RIGHTS RESERVED.
- change ventrally, no change dorsally
inductive environment - answer✔genotypes
selective environment - answer✔alternative phenotypes
ecdysone - answer✔the major steroid hormone in insects and plays essential roles in
coordinating developmental transitions such as larval molting and metamorphosis through its
active metabolite 20E
enabling mutation - answer✔refers to a genetic alteration conferring environmental sensitivity
to a phenotype that was originally not plastic. this allows the expression of plasticity which can
thereafter be shaped by selection
genetic accommodation - answer✔refers to the process by which selection shapes the
properties and/or magnitude of a plastic response
genetic assimilation - answer✔refers to the process of genetic accommodation by which there
is the fixation of what were previously induced phenotypes
tobacco hornworms - answer✔only green
tomato hornworms - answer✔green when >28C, black otherwise
black mutant tobacco hornworms - answer✔show green when heat shocked
abdomina and thoracic ligations - answer✔- ligation behind the first abdominal segment, the
anterior compartment of larvae from the polyphenic line changed color upon heat shock, but
the posterior did not. monophenic line remained black
- ligation placed behind the neck, no color change response to heat shock was observed in
either line
corpora allata - answer✔produces JH
prothoracic gland - answer✔produces ecdysone
sensitivity to JH - answer✔monophenic lines differ in sensitivity to JH
Buying time hypothesis - answer✔suggests that when a colonizing a new habitat or facing
environmental perturbation, a "plastic population" can first adjust to the new conditions by
expressing distinct plastic phenotypes and thereby persist enough time for new mutations to
happen and fuel adaptive evolution
Plasticity-first hypothesis - answer✔proposes that plasticity can initiate and accelerate the rate
of phenotypic change in that plastic adaptive phenotypes can emerge earlier and faster than
phenotypic changes due to genetic mutation
2|Page
