Nature of Diversity
Study questions for Exam 2
Birds:
1. What is the working hypothesis for the sequential steps in the evolution of flight feathers?
Ornamentation à endothermy à flight
2. How did the evolution of flight by birds affect Pterosaur evolution?
Pterosaurs increased in size
3. Which niches did birds colonize after dinosaurs went extinct?
Niche of top terrestrial predators in South America
4. Name some of the Paleognath birds, and a couple distinguishing characteristics.
Elephant bird, ostrich, emu; jaw is primitive and reptilian, omnivore
5. Among the Neognaths, which groups have a penis?
Galloanserae
6. What is the presumed relationship between mate selection by females, reduction of the penis, and
enhancement of courtship displays in birds?
No penis is adaptive and reinforces courtship; females select for most extravagant courtship =
those males reproduce
7. Why do hummingbirds have such high energy demands, and how do they meet/reduce these
demands?
Heart beats quick, wings flap quick, travel far; gain 25-40% body weight before migration, fly at
day when nectar is more abundant, use tail winds
8. What is ‘nest parasitism’ and which birds are named for this behavior?
Lay eggs in another’s nest; Eurasian common cuckoo/yellow billed cuckoo
9. How does wing size change as bird mass increases; proportionately or disproportionately? Why?
Proportionate increase to maintain same wing loading
10. How does the shape of the wing influence the aerodynamics of speed and maneuverability?
Higher aspect (L:W) ratio = less maneuverable = less drag (long and skinny)
Lower aspect (L:W) ratio = more maneuverable = drag (short and fat)
11. What is vortex drag and how do birds reduce it and exploit it (in v formation?)
, Vortex drag from wing tip vertices; vortex drag off leading bird creates updraft that lifts behind
birds; negatives downdraft and turbulence
12. What is a ‘ring species complex” and why is it such a good example of how continuous genetic
variation can lead to the formation of new species?
Can interbreed; populations diverged but maintained enough gene flow to produce new
intermediates
13. What adaptations do kingfishers and woodpeckers have to their unique lifestyles?
Hybrid bone wraps around skull to absorb shock
14. Which group of birds has the most species?
Passeriform (perching bird)
16. A recent article on birds decline suggested that bird numbers had decreased by 30% over the last 40
years. Although this is a staggering number, why might it not indicate dramatic species loss?
Most loss is in abundant species without threat of extinction
17. What are some likely reasons for this decline?
Loss of habitat (especially prairie/forest), overexploitation of species
18. What does it mean that ‘Reptilia’ is a polyphyletic clade?
Does not contain all descendants from an ancestor; crocodiles more closely related to birds but
grouped with reptiles
Herps!
1. The first forests evolved in the Carboniferous. What effect did this (and their sequestration of carbon
in sediments) have on the environment?
Many amphibians; sequestration of carbon became coal deposits
2. What are the primary benefits for vertebrates like Tiktaalik of colonizing land?
After Pangaea, world became drier; fewer predators on land, less resource competition
3. For modern frogs, what is another likely benefit of colonizing land, especially at the egg stage? How
does the use of temporary pools for egg-laying support this idea?
World became drier after Pangaea, jelly protein on eggs, temporary pools to keep eggs moist
4. Approximately 20% of frog species have eliminated the tadpole stage and have direct development or
even viviparity. What is the tradeoff involved here, between number of offspring the female can
produce and the probability of offspring survival?
No tadpole stage = fewer offspring = higher probability of survival
Study questions for Exam 2
Birds:
1. What is the working hypothesis for the sequential steps in the evolution of flight feathers?
Ornamentation à endothermy à flight
2. How did the evolution of flight by birds affect Pterosaur evolution?
Pterosaurs increased in size
3. Which niches did birds colonize after dinosaurs went extinct?
Niche of top terrestrial predators in South America
4. Name some of the Paleognath birds, and a couple distinguishing characteristics.
Elephant bird, ostrich, emu; jaw is primitive and reptilian, omnivore
5. Among the Neognaths, which groups have a penis?
Galloanserae
6. What is the presumed relationship between mate selection by females, reduction of the penis, and
enhancement of courtship displays in birds?
No penis is adaptive and reinforces courtship; females select for most extravagant courtship =
those males reproduce
7. Why do hummingbirds have such high energy demands, and how do they meet/reduce these
demands?
Heart beats quick, wings flap quick, travel far; gain 25-40% body weight before migration, fly at
day when nectar is more abundant, use tail winds
8. What is ‘nest parasitism’ and which birds are named for this behavior?
Lay eggs in another’s nest; Eurasian common cuckoo/yellow billed cuckoo
9. How does wing size change as bird mass increases; proportionately or disproportionately? Why?
Proportionate increase to maintain same wing loading
10. How does the shape of the wing influence the aerodynamics of speed and maneuverability?
Higher aspect (L:W) ratio = less maneuverable = less drag (long and skinny)
Lower aspect (L:W) ratio = more maneuverable = drag (short and fat)
11. What is vortex drag and how do birds reduce it and exploit it (in v formation?)
, Vortex drag from wing tip vertices; vortex drag off leading bird creates updraft that lifts behind
birds; negatives downdraft and turbulence
12. What is a ‘ring species complex” and why is it such a good example of how continuous genetic
variation can lead to the formation of new species?
Can interbreed; populations diverged but maintained enough gene flow to produce new
intermediates
13. What adaptations do kingfishers and woodpeckers have to their unique lifestyles?
Hybrid bone wraps around skull to absorb shock
14. Which group of birds has the most species?
Passeriform (perching bird)
16. A recent article on birds decline suggested that bird numbers had decreased by 30% over the last 40
years. Although this is a staggering number, why might it not indicate dramatic species loss?
Most loss is in abundant species without threat of extinction
17. What are some likely reasons for this decline?
Loss of habitat (especially prairie/forest), overexploitation of species
18. What does it mean that ‘Reptilia’ is a polyphyletic clade?
Does not contain all descendants from an ancestor; crocodiles more closely related to birds but
grouped with reptiles
Herps!
1. The first forests evolved in the Carboniferous. What effect did this (and their sequestration of carbon
in sediments) have on the environment?
Many amphibians; sequestration of carbon became coal deposits
2. What are the primary benefits for vertebrates like Tiktaalik of colonizing land?
After Pangaea, world became drier; fewer predators on land, less resource competition
3. For modern frogs, what is another likely benefit of colonizing land, especially at the egg stage? How
does the use of temporary pools for egg-laying support this idea?
World became drier after Pangaea, jelly protein on eggs, temporary pools to keep eggs moist
4. Approximately 20% of frog species have eliminated the tadpole stage and have direct development or
even viviparity. What is the tradeoff involved here, between number of offspring the female can
produce and the probability of offspring survival?
No tadpole stage = fewer offspring = higher probability of survival
