Preview Material - Exam 1 Spring 2007

Preview Material for Exam 1 - Spring 2007
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Considering the hazardous driving conditions after the recent ice storm, Fred decided to walk to all of his classes from Morrison Hall. Thinking it might be cold, he put a sweatshirt on over a T-shirt and grabbed a jacket as well. He wore jeans and a thin pair of tennis shoes to round out his wardrobe. He slung his backpack over his shoulder and started off on his adventure. While walking on McElroy, he was surprised by the brisk (20 mph), 18°F wind coming from his left and noticed the left side of his face getting cold. As he turned onto Monroe, he noticed that the cold did not affect the back of his head nearly as much as it had the side of his face. When he left his next class, he stood near the wall of the library to talk to a friend. He noticed he was warmer than during his earlier wait even though the outside temperature was still 18°F.

Scientists have observed population declines of the mountain yellow-legged frog (Rana muscosa) in southern California over a period of time. Researchers and wildlife activists are seeking to explain the disappearance of the yellow-legged frog, among other frog species. Several years ago, a bullfrog species (Rana catesbeiana) was introduced to the area. The bullfrog is a non-native species and a known predator of other, smaller frogs.

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You lead a team of field biologists to collect data in a small region of Southern California over a period of 3 years. Your results are found in the table below.

Collection Date	Number of Bullfrogs	Number of Yellow-Legged Frogs
1. January 2, 2004	10	20
2. August 1, 2004	16	24
3. January 1, 2005	22	18
4. August 1, 2005	26	14
5. January 3, 2006	30	9
6. August 2, 2006	34	8

Among other places, the Arctic Cod (Boreogadus saida, a fish) resides off the coast of northern Russia where water temperatures remain a fairly constant 3º C year round. Orca or Killer Whales (Orcinus orca) occupy the same coastal waters as the Arctic Cod. These marine mammals are shaped similar to the Arctic Cod but are much, much larger. Killer Whales are endotherms; Arctic Cod are ectotherms..

Killer Whales source

Arctic Cod source

Lymphocytic choriomeningitis virus (LCMV) can lead to severe birth defects in humans. Pregnant women contract it from pet rodents (e.g. hamsters) that have contacted wild ones (e.g. house mice).

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A scientist was interested in the effect of different commercial fishing methods on fish size. He examined the methods used in three different lakes (A,B,C). In Lake A, the boats use nets that catch the largest 50% of the adult fish, in Lake B, the boats use nets that catch the smallest 50% of the adult fish, and in Lake C, they use electrofishing boats that catch fish of all sizes. None of these methods are 100% effective (i.e. some fish of each size are left behind). After several years, the fish in Lake A are plentiful, but very small and those in Lake B are very large, even those that hatched AFTER the fishing began. The fish eat snails. Bigger snails are more difficult to eat and only larger fish can eat larger snails. If snails are large enough, no fish can eat them.

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