Animal Physiology

1. The increase in insulation that mammals gain when they increase their fur or hair density in preparation for winter aids in reducing heat loss through thermal radiation. Using the physics of heat transfer, EXPLAIN how this works. Piloerection (hair standing up from the skin) increases this layer of insulation highly effectively in terrestrial endotherms, but not aquatic endotherms who instead rely on blubber for insulation. EXPLAIN WHY.

2. Cichlid fish like Tropheus brichardi are unusual among fish because they are herbivorous. Using the figure below explain why gut length strongly correlates with food quality

3. Why is acclimatization important for freeze avoidance/ tolerance? For example, why can a summer acclimated tree frog not tolerate freezing?

4. When animals are faced with extreme environmental conditions they have two options: avoid or tolerate. Choose an extreme environmental condition (oxygen, water, temperature, etc.) and give a cost-benefit analysis for both strategies.

5. The veterinary hospital at the University of Franca in Sao Paulo, Brazil had five giant anteaters (Myrmecophaga tridactyla) needing surgical treatment under anesthesia for a variety of disorders. Unfortunately, there are no doses indicated on any anesthesia for application to anteaters. How did these surgeons handle this problem? Why should this work? What might make their solution not work?   

6. By varying the number of double bonds in the hydrophobic tails of phospholipids, animals can maintain the integrity of their cell membranes in the face of changes in TB. How do they achieve this?

7. Differentiate oxygen deficit and oxygen debt. Draw these on a labeled graph and explain what you’ve drawn. Why are they different (numerically)? Draw and explain how EPOC might be different if you compared a frog (primarily glycolytic) vs. toad (blend of glycolytic/ oxidative muscle fibers)

8. Suppose you discovered a previously unknown organism. How would you go about classifying this organism?

9. Science Magazine published a perspective on the genome sequence of sea urchins (https://www.sciencemag.org/cgi/reprint/314/5801/939.pdf) in which the importance of this species for genetic analysis is described. How can our knowledge of the sea urchin genome help us understand vertebrate genomics? (You do not have to read this article in order to answer the question though it may help you – it is an interesting paper and worth reading for its own sake).

10. Describe the negative feedback loop for nutrition. Give an example of how this feedback loop works effectively.

11. Why can we use oxygen consumption as a measure of metabolic rate? How do we know precisely how much oxygen is needed to burn each type of fuel?

12. Calorimetry is most directly measured as _____________ ___________________, but, as this is cumbersome, indirect calorimetry is normally used to estimate metabolic rate by measuring rates of _____________________ __________________.

13. Can an animal know what nutrients/minerals it needs to consume in its diet? How would you design an experiment to either support or disprove this? Draw a graph showing how your expected data would support your hypothesis. Defend your answer.

14. Draw a graph showing the temperature-dependence of metabolic rate on poikilothermic ectotherms and homeothermic endotherms. Explain why they are different

15. How do animals absorb food for which they are unable to make enzyme to break that food down?

16. Negative feedback mechanism maintains homeostatic control of physiological variables. Draw a feedback loop with the basic components identified and explain what happens when something perturbs the system. Explain the importance of gain in a feedback loop. You can use either a biological or non-biological example.

17. The solubility of oxygen is inversely proportional to temperature. How would this affect the pejus temperature for a freshwater fish? Draw a figure (graph) that illustrates your answer.

18. Hemoglobin, hemocyanin, hemerythrin, and chlorocruorin are four major types of ______that increase the ______ of oxygen carried in the blood

19. The P50 for hemoglobin saturation in diving emperor penguins, Aptenodytes forsteri, has been measured to be 28 mmHg at pH 7.5 compared with a normal P50 for the domestic chicken, Gallus gallus domesticus, of ~46 mmHg at pH 7.5 (standard conditions). Draw and label an oxygen dissociation curve that shows the affinities for both of these species. Why are these lines different? Based on the O2 dissociation curve you have drawn, explain the adaptive advantage of the lower P50 in the penguins.

20. In crocodilian hearts, an increase in pulmonary arterial resistance will cause what to happen to Pao2 in the systemic arteries? Why? How is this controlled?

21. Draw and explain a grapg showing the dependence of on body temperature for a bullfrog relative to that of netural watet. Hint:

22. Draw and label a graph showing how metabolic rate changes as a function of mass across the size range of monitor lizards from the genus Varanus. Explain your graph.

23. Why does the Red Sands desert have such a high diversity of lizard species?

24. The cheetah, Acinonyx jubatus, is one of the fastest land mammals. Cheetahs spend much of their time resting, but can run at very high speeds when hunting. What changes can occur in the oxygen transport cascade to accommodate this increase in metabolic rate? Distinguish acute changes (with the onset of exercise) from chronic changes (or acclimatization to increased O2 demand in any mammal).

25. Even though air flow is tidal into and out of avian tracheae, actual air flow across the parabronchial lung is both _____________________ and _______________________ because of changes in volume of the dorsal and ventral air sacs. Blood flow across the gas exchange surface runs perpendicular to airflow in a design called _______________________________________________.

26. When I open a bottle of Dr. Pepper, it fizzes and bubbles. Why?

27. The aquatic Lake Titicaca frog, Telmatobius culeus, is endemic to high Andean lakes (3812 meters above sea level) and has greatly reduced lungs, but elaborated skinfolds which are well perfused. It has one of the lowest recorded metabolic rates for amphibians at 14.1 μL g-1 h-1. It also has the smallest reported erythrocyte volume (394 μ3) for any amphibian, and a reduced O2 carrying capacity of its blood at 11.7 vol %. Based on your knowledge of the oxygen carrying capacity of blood, what might explain the low carrying capacity in T. culeus? When these frogs are submerged at the bottom of these alpine lakes, they occasionally bob by pushing off the lake bottom with their hind legs and floating back down again. What might be the function of this bobbing behavior? How would you quantify this bobbing function?

28. PB in my lab was 757mmHg this morning. What is the Po2 of the artificial cerebral spinal fluid (a salt solution equilibrated with room air) being perfused across the brainstem slices from which Mauricio is recording neural activity?

29. How does the Root effect change oxygen carrying capacity in fish? Draw this as a graph, label, and explain.

30. The aquatic Lake Titicaca frog, Telmatobius culeus, is endemic to high Andean lakes (3812 meters above sea level) and has greatly reduced lungs, but elaborated skinfolds which are well perfused. It has one of the lowest recorded metabolic rates for amphibians at 14.1 μL g-1 h-1. It also has the smallest reported erythrocyte volume (394 μ3) for any amphibian, and a reduced O2 carrying capacity of its blood at 11.7 vol %. Based on your knowledge of the oxygen carrying capacity of blood, what might explain the low carrying capacity in T. culeus? When these frogs are submerged at the bottom of these alpine lakes, they occasionally bob by pushing off the lake bottom with their hind legs and floating back down again. What might be the function of this bobbing behavior? How would you quantify this bobbing function?

31. Why are peptide hormones like insulin often stored in secretory vesicles?

32. Based on the figure below taken from JEB 2001 (204; 959-966), Why would crustaceans need ion transporters? How do they get them? How can a researcher know what transporters are available? Which ones are in use? Why might these be different?

33. The osmotic U/P ratio reflects the water balance strategy of an animal. Match the osmotic U/P ratios with their respective strategies below. AT WHAT COST________________

a. Osm U/P < 1 _____ urine hyperosmotic to plasma

b. Osm U/P = 1 _____ urine hyposmotic to plasma

c. Osm U/P > 1 _____ urine isosmotic to plasma

34. One of the important characteristic of bird eggs is that they are calcifies to provide a hard shell. Because the growing embryo needs to exchange respiratory gases (o2 and co2) across the shell, it has to have holes in it. How many holes are present (relative permeability) in the shell of the egg is called its porosity. Why is porosity not linearly related to altitude? Explain the confounding variables shown in the figure below.

35. Here in Dayton, our arterial Po2 is normally 100 torr. If we ascend in altitude to 6000 meters while climbing in Alaska, what will our inspired Po2 be? What physiological adjustments do we make to accommodate this new Po2? Note: 1 kPa=7.5 mmHg

36. The temperature-dependence of dive duration is shown below for two species of sea snakes. Data are from Vinay Udyawer et al. J Exp Biol 2016; 219:3447-3454. Explain why this temperature-dependence of dive duration is expected based on physiological principles.

Water Temperature (°C)

37. Draw and label and explain a graph describing the allometric scaling of gravitational forces.

Using the figure below, explain why the atrioventricular valve and the aortic valve are either open or closed when they are.

Examine the figure below. Explain why these lines are different from each other at higher [Na+]