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18 terms

Amniotes II

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Which of the following likely helped sauropods eat vast quantities of food?
lack of molars
It is estimated that sauropods lived on Earth for about how long?
140 million years
You are a paleontologist and discover a new species of sauropod. Which of the following convinced you to put it in that group of dinosaurs?
It had an extremely long neck.
Compared to a human, the heart rate of a sauropod was ______________.
very low
Metabolically, it is believed that sauropods were most similar to modern-day _____________.
mammals
Which of these are amniotes?

egg-laying mammals
amphibians
fishes
placental mammals
More than one of these is correct
More than one of these is correct
Which of the following is characteristic of most extant reptiles and most extant mammals?
rib cage ventilation
At the end of which period did most dinosaurs and pterosaurs become extinct?
Cretaceous
Which of the following are the only extant animals that descended directly from dinosaurs?
birds
Examination of the fossils of Archaeopteryx reveals that, in common with extant birds, it had
feathers
Why is the discovery of the fossil Archaeopteryx significant? It supports the
phylogenetic relatedness of birds and reptiles.
What is the single unique characteristic that distinguishes extant birds from other extant vertebrates?
feathers
Due to its system of nine air sacs connected to the lungs, the respiratory system of birds is arguably the most effective respiratory system of all air-breathers. Upon inhalation, air first flows into posterior air sacs, then into the lungs, and then into anterior air sacs on the way to being exhaled. Thus, there is one-way flow of air through the lungs, along thousands of tubules called parabronchi.


If the inner lining of the air sacs is neither thin nor highly vascularized, then what can be inferred about the air sacs?
They cannot be sites of gas exchange between air and blood.
Due to its system of nine air sacs connected to the lungs, the respiratory system of birds is arguably the most effective respiratory system of all air-breathers. Upon inhalation, air first flows into posterior air sacs, then into the lungs, and then into anterior air sacs on the way to being exhaled. Thus, there is one-way flow of air through the lungs, along thousands of tubules called parabronchi.


Some bird bones are hollow rather than honeycombed. The hollow bones mostly contain air sacs. The replacement of bone marrow with air sacs is properly understood as an adaptation to

reduce the weight of the bird.
facilitate flight.
eliminate the functions that marrow performs.
All three of the options listed are correct.
Only two of the options listed are correct.
Only two of the options listed are correct.
Due to its system of nine air sacs connected to the lungs, the respiratory system of birds is arguably the most effective respiratory system of all air-breathers. Upon inhalation, air first flows into posterior air sacs, then into the lungs, and then into anterior air sacs on the way to being exhaled. Thus, there is one-way flow of air through the lungs, along thousands of tubules called parabronchi.


Birds generate a lot of heat, especially during flight. Yet the adipose tissue under their skin and the feathers atop their skin make it difficult to eliminate excess heat across the skin. Which of the following alternatives can absorb body heat and eliminate it from the bird most effectively?
air in the air sacs
If Archaeopteryx had air sacs, then which of its features would have had the opposite effect on enabling Archaeopteryx to fly long distances from that provided by air sacs?
1. teeth
2. contour feathers
3. wing claws
4. long tail with many vertebrae
1, 3, and 4
Which type of bird is most likely to need air sacs to reduce its weight?
birds that migrate long distances
Which of the following is/are true
Craniates have a head and neural crest cells.
Animals have a cranium, fur, and mammary glands.
Reptiles can be defined as ectothermic amniotes.
Craniates have a head and neural crest cells