KEY--Test 2 Practice

1. If your blood hemoglobin is 60% saturated with oxygen gas, what is the partial pressure of oxygen in solution?

According to the class handout, 60% oxygen saturation of hemoglobin (Y axis) occurs at 35 mm oxygen pressure in the blood,

2. Compare and contrast the sandworm and the camel in terms of desert adaptation. Include (1) water use, (2) heat avoidance, (3) digestive chemistry.

3. Based on your graph of water saturation: Suppose air that is raining at 40 degrees F warms up to 80 degrees F. What is the percent water saturation? How does the air feel?

At 40 degrees F, if it is raining the air must be saturated with water; that is, 0.75% of the air consists of water vapor.

At 89 degrees F, the air can hold up to 2.3% water vapor.
So the relative humidity = 0.75% / 2.3% = 0.32 = 32%
Be careful when interconverting percent with a fraction!
32% saturation feels somewhat dry, though less dry than a desert.

4. Sketch the main cycle of carbon dioxide, water, and other necessary components in an ecosystem on Earth. Explain how the cycle differs from that proposed for Dune.

5. This table shows the percent relatedness of several pairs of dinosaur species. If the dinosaur mutation rate is 0.13% per million years, draw a tree of phylogeny (divergence) including all the species.

 Dinosaur species
A
B
C
D
E
F
A
 Dilphosaurus
100
70
90
70
85
85
B
 Hadrosaurus
70
100
70
80
70
70
C
 Procompsognathus
90
70
100
70
85
85
D
 Stegosaurus
70
80
70
100
70
70
E
 Tyrannosaurus
85
70
85
70
100
95
F
 Velociraptor
85
70
85
70
95
100

6. What is the proportion of bicarbonate to CO2 in your blood, if your blood pH is: pH 7.2?  pH 7.4?  pH 7.6?  What is the consequence of each pH level for your body ?

7. Suppose you measure the hydrogen ion concentration of a soil sample (1.2 x 10-5 Molar) and of lemon juice (8.3 x 10-2 Molar). Are they acidic or basic? Which has greater acidity?

The soil sample pH  is: -log10(1.2 x 10-5 Molar) = pH 4.92
The lemon juice pH  is: -log10(8.3 x 10-2 Molar) = pH 1.08
The lemon is stronger acid than the soil sample.
(Note: This particular lemon is more acidic than usual.)

8. The main weak acid in citrus fruits is citric acid (Ka = 7.5 x 10-4). If an orange contains 10-3 Molar citric acid, what is the pH of the orange juice?

We actually didn't quite get to this topic this year, so don't worry about it.

9. Explain how the Sharers used lifeshaping of animals and plants to accomplish aims that we accomplish with machines.

10. Compare and contrast the adaptation of Fremen and of Sharers to their respective environments. Which adaptations are genetic, and which are cultural? Which adaptations involve cooperation with other life forms? How do the Fremen and the Sharers use their adaptations to resist foreign invasion?

11. Describe a typical ecosystem of each type: intertidal zone (marsh); coastal shelf; open ocean; sea floor and vent community. Explain how the types are similar, and how they differ. How do they relate to the ecosystem of Shora?

12. In the film Avatar, explain how organisms compete, and how they work together. Describe real-life examples of symbiosis between different species that act similarly to those in Avatar.

13. Explain how symbiosis works in ecosystems. How does evolution favor symbiosis? How do symbionts maintain their partnership without each destroying the other?

14. The phylogeny and divergence of life forms on Pandora implies what assumptions about inheritance of genetic information? The function of neural extensions suggests another possiblity for how genes are inherited. How can both these models be correct? What are real-life examples of horizontal gene transfer?

15. Suppose that a type of dew collector collects 50 liters water per meter squared, per year. What size area of collector would be needed to collect water continually for a household of ten people?

16. The Fremen face a problem in the "watering" of Arrakis. Where does the water come from? What will happen if they succeed? How do their problems relate to ours in our use of water in agriculture?

17. Explain why and how evolution generates many divergent species of a given class of life form. Why does evolution not produce the "one" fittest species?  Describe specific examples.

18. Suppose that even without the unobtainium miners, Pandora's herd of sturmbeasts have declined from 15,000 to 12,000 in the past three years. If their exponential decline continues at the present rate, how many will remain ten years from now?  Propose a hypothesis to explain their decline, and an experiment to test your hypothesis.

19. In The Devil in the Dark, we saw a creature that lives in extreme acid. Suppose that a creature whose blood is at pH 7.4 tries to live in an environment at pH 2 or at pH 12. What problems would this creature have to solve?