UCLA- EEB 100 Midterm 1 questions
and answers graded A+
True or False: Adaptations depend on the presence of others in a population. - correct answer
✔✔ True, fitness benefits of adaptations are relative to the fitness of others in a population.
True or False: Exaptation’s are evolved traits that, as a result of a changing environment, are no
longer adaptive. - correct answer ✔✔ False, exaptation’s are traits that evolved initially or one
purpose that later become co-opted for another
True or False: Natural Selection causes individuals to change when they need to adapt to
changes in envio. - correct answer ✔✔ False, natural selection cannot change existing
individuals
True or False: Descent with modification applies only to large animals and plants and not to
smaller organisms like bacteria or protozoans - correct answer ✔✔ False, descent with
modification applies to all living organisms
True or False: Natural selection theory provides a means for why some changes spread through
a species while others do not - correct answer ✔✔ True, if an adaption contributes to higher
reproductive fitness than an alternative trait, then that trait will spread through the population
True or False: Natural selection favors individuals that can survive the best - correct answer ✔✔
False, NS focuses on reproduction (fitness) rather than life time
Suppose female lizards with reddish throats produce more eggs than females with orange
throats. Why might the females with orangey throats persist in the population, is it possible that
the orangey throats are an evolved adaptation? - correct answer ✔✔ Yes, even though red
,throated lizards produce more eggs, orange throat lizards may be able to produce more
offspring that survive until they have the ability to reproduce
Lemmings leave when they are living when population densities get very high because they
have better chances of reproducing in places where the population density is lower - correct
answer ✔✔ Darwinian natural selectionist hypothesis: Lemmings are motivated by their own
individual reproductive potential
Lemmings leave when they are living when population densities get very high because as the
dispersing lemmings die off they leave the species in the hands of the best survivors - correct
answer ✔✔ Group selection hypothesis: Lemmings are leaving to ensure the survival of the
remaining population
Lemmings leave where they are living when population densities get very high because the risk
of inbreeding increases at high population densities, which favors males and females to find
genetically dissimilar mates in other areas - correct answer ✔✔ Darwinian natural selectionist
hypothesis: Lemmings are motivated to leave by their own individual reproductive potential
If a trait has an adaptive value then it: - correct answer ✔✔ Confers a reproductive advantage
on individuals
Male Red Backed spiders are dwarfed by their female counterparts. After mating, males will
sometimes summersault into the mouth of the mated female where he is devoured. Why has
copulatory suicide evolved in redback spiders? Is there a potential cheater problem?
Create a hypothesis based on group selection theory - correct answer ✔✔ By male spiders
participating in copulatory suicide it shows that male spiders perform suicide due to wanting to
reduce the overall egg fertilization rate and prevent over-population
Male Red Backed spiders are dwarfed by their female counterparts. After mating, males will
sometimes summersault into the mouth of the mated female where he is devoured. Why has
copulatory suicide evolved in redback spiders? Is there a potential cheater problem?
, Create a hypothesis based on individual selection hypothesis - correct answer ✔✔ By male
spiders participating in copulatory suicide due to the individual selection hypothesis it shows
that they are motivated by providing the female spider a free male which will then enhance the
overall rate of egg production
Male Red Backed spiders are dwarfed by their female counterparts. After mating, males will
sometimes summersault into the mouth of the mated female where he is devoured. Why has
copulatory suicide evolved in redback spiders?
Is there a potential cheater problem? - correct answer ✔✔ If non-suicidal males feritizlied more
eggs than those who do commit suicide then non suicidal genotypes will take over the
population
The behavior is learned - correct answer ✔✔ Genetic-developmental
Wing flipping scares some predators away - correct answer ✔✔ Adaptive value
The behavior is the product of a special set of muscle contractions - correct answer ✔✔ Sensory
motor
The activity of N2RB gene declines in older mice and causes a decline in learning ability." Some
have suggested that this is beneficial because it means older mice cannot forage as efficiently as
they once did, which frees up resources for the next generation. This hypothesis is based on
group selection because: - correct answer ✔✔ It is group selection due to the trait appearing
selfless to benefit the survival of the species as a whole
All primates appear to fear snakes before ever encountering a real snake - correct answer ✔✔
Phylogentic or historical due to it originating from shared primate ancestry
and answers graded A+
True or False: Adaptations depend on the presence of others in a population. - correct answer
✔✔ True, fitness benefits of adaptations are relative to the fitness of others in a population.
True or False: Exaptation’s are evolved traits that, as a result of a changing environment, are no
longer adaptive. - correct answer ✔✔ False, exaptation’s are traits that evolved initially or one
purpose that later become co-opted for another
True or False: Natural Selection causes individuals to change when they need to adapt to
changes in envio. - correct answer ✔✔ False, natural selection cannot change existing
individuals
True or False: Descent with modification applies only to large animals and plants and not to
smaller organisms like bacteria or protozoans - correct answer ✔✔ False, descent with
modification applies to all living organisms
True or False: Natural selection theory provides a means for why some changes spread through
a species while others do not - correct answer ✔✔ True, if an adaption contributes to higher
reproductive fitness than an alternative trait, then that trait will spread through the population
True or False: Natural selection favors individuals that can survive the best - correct answer ✔✔
False, NS focuses on reproduction (fitness) rather than life time
Suppose female lizards with reddish throats produce more eggs than females with orange
throats. Why might the females with orangey throats persist in the population, is it possible that
the orangey throats are an evolved adaptation? - correct answer ✔✔ Yes, even though red
,throated lizards produce more eggs, orange throat lizards may be able to produce more
offspring that survive until they have the ability to reproduce
Lemmings leave when they are living when population densities get very high because they
have better chances of reproducing in places where the population density is lower - correct
answer ✔✔ Darwinian natural selectionist hypothesis: Lemmings are motivated by their own
individual reproductive potential
Lemmings leave when they are living when population densities get very high because as the
dispersing lemmings die off they leave the species in the hands of the best survivors - correct
answer ✔✔ Group selection hypothesis: Lemmings are leaving to ensure the survival of the
remaining population
Lemmings leave where they are living when population densities get very high because the risk
of inbreeding increases at high population densities, which favors males and females to find
genetically dissimilar mates in other areas - correct answer ✔✔ Darwinian natural selectionist
hypothesis: Lemmings are motivated to leave by their own individual reproductive potential
If a trait has an adaptive value then it: - correct answer ✔✔ Confers a reproductive advantage
on individuals
Male Red Backed spiders are dwarfed by their female counterparts. After mating, males will
sometimes summersault into the mouth of the mated female where he is devoured. Why has
copulatory suicide evolved in redback spiders? Is there a potential cheater problem?
Create a hypothesis based on group selection theory - correct answer ✔✔ By male spiders
participating in copulatory suicide it shows that male spiders perform suicide due to wanting to
reduce the overall egg fertilization rate and prevent over-population
Male Red Backed spiders are dwarfed by their female counterparts. After mating, males will
sometimes summersault into the mouth of the mated female where he is devoured. Why has
copulatory suicide evolved in redback spiders? Is there a potential cheater problem?
, Create a hypothesis based on individual selection hypothesis - correct answer ✔✔ By male
spiders participating in copulatory suicide due to the individual selection hypothesis it shows
that they are motivated by providing the female spider a free male which will then enhance the
overall rate of egg production
Male Red Backed spiders are dwarfed by their female counterparts. After mating, males will
sometimes summersault into the mouth of the mated female where he is devoured. Why has
copulatory suicide evolved in redback spiders?
Is there a potential cheater problem? - correct answer ✔✔ If non-suicidal males feritizlied more
eggs than those who do commit suicide then non suicidal genotypes will take over the
population
The behavior is learned - correct answer ✔✔ Genetic-developmental
Wing flipping scares some predators away - correct answer ✔✔ Adaptive value
The behavior is the product of a special set of muscle contractions - correct answer ✔✔ Sensory
motor
The activity of N2RB gene declines in older mice and causes a decline in learning ability." Some
have suggested that this is beneficial because it means older mice cannot forage as efficiently as
they once did, which frees up resources for the next generation. This hypothesis is based on
group selection because: - correct answer ✔✔ It is group selection due to the trait appearing
selfless to benefit the survival of the species as a whole
All primates appear to fear snakes before ever encountering a real snake - correct answer ✔✔
Phylogentic or historical due to it originating from shared primate ancestry
