BIOS 280 Exam 2 Review; Questions and Answers Rated
A+
1. What does it mean to say that a signal is reliable? Why are sexually select signals expected
to be reliable? What might ensure that sexually selected signal is reliable? Correct Ans-
Reliable signal- costly to produce
Ex. Long call for a frog might cause easier predation
Long tail of bird might cause easier predation, more energy spent flying
Opportunity cost- time spent on a signal is wasted, could be eating, migrating etc.
2. Describe runaway sexual selection. Correct Ans-Male trait preferred by females that
doesn't indicate male quality Ex. stalk-eyed flies
3. What is sensory bias and how is it related to sexual selection? Describe some experimental
evidence of sensory bias. Correct Ans-Sensory bias- viability selection on female sensory
system, female attraction for male trait that is absent (preexisting bias), mutation produces a
rudimentary male display trait (exploitation
-hypothesis to how sexual selection might have started
Ex. Wild guppies (fish)- flower drops orange fruit, fish like to eat, male fish generate orange
spots, female guppies have strong preference for orange
, BIOS 280 Exam 2 Review; Questions and Answers Rated
A+
4. Why are "normal" sex roles and sexual dimorphism reversed in some species? Correct
Ans-Sea horses- males get pregnant, male choose for females
Sexual selection stronger on females
Males attracted to larger females with fewer spots
→ reversed sexual dimorphism
5. What is a species? Provide a general definition and two more specific definitions that
attempt to specify more precisely the meaning of the general definition. Correct Ans-
Species- smallest evolutionary independent unit
Biological Species Concept- species are groups of actually or potentially interbreeding natural
populations, which are reproductively isolated from other such groups
Phylogenetic Species Concept- whatever the smallest group that we can identify on a
phylogenetic tree is a species
6. What are some of the limitations and drawbacks of the biological species concept? Of the
phylogenetic species concept? Correct Ans-Drawbacks of Biological Species Concept-
Microbe are not sexually producing, extinct organisms, hybrids, Organisms that don't
naturally overlap
A+
1. What does it mean to say that a signal is reliable? Why are sexually select signals expected
to be reliable? What might ensure that sexually selected signal is reliable? Correct Ans-
Reliable signal- costly to produce
Ex. Long call for a frog might cause easier predation
Long tail of bird might cause easier predation, more energy spent flying
Opportunity cost- time spent on a signal is wasted, could be eating, migrating etc.
2. Describe runaway sexual selection. Correct Ans-Male trait preferred by females that
doesn't indicate male quality Ex. stalk-eyed flies
3. What is sensory bias and how is it related to sexual selection? Describe some experimental
evidence of sensory bias. Correct Ans-Sensory bias- viability selection on female sensory
system, female attraction for male trait that is absent (preexisting bias), mutation produces a
rudimentary male display trait (exploitation
-hypothesis to how sexual selection might have started
Ex. Wild guppies (fish)- flower drops orange fruit, fish like to eat, male fish generate orange
spots, female guppies have strong preference for orange
, BIOS 280 Exam 2 Review; Questions and Answers Rated
A+
4. Why are "normal" sex roles and sexual dimorphism reversed in some species? Correct
Ans-Sea horses- males get pregnant, male choose for females
Sexual selection stronger on females
Males attracted to larger females with fewer spots
→ reversed sexual dimorphism
5. What is a species? Provide a general definition and two more specific definitions that
attempt to specify more precisely the meaning of the general definition. Correct Ans-
Species- smallest evolutionary independent unit
Biological Species Concept- species are groups of actually or potentially interbreeding natural
populations, which are reproductively isolated from other such groups
Phylogenetic Species Concept- whatever the smallest group that we can identify on a
phylogenetic tree is a species
6. What are some of the limitations and drawbacks of the biological species concept? Of the
phylogenetic species concept? Correct Ans-Drawbacks of Biological Species Concept-
Microbe are not sexually producing, extinct organisms, hybrids, Organisms that don't
naturally overlap
