Thinking Scientifically

1. Excess nutrients in a lake or in the ocean can greatly disrupt biological communities. Organisms die. How can this happen, if life depends upon a supply of nutrients?

2. Researchers and citizens in Prairie City, Iowa, are reconstructing the prairie by collecting seeds from remnants and reintroducing animals. Which biomes and aquatic ecosystems discussed in the chapter might be possible to reconstruct, and which not?

3. Cite two biomes or aquatic ecosystems where population bottlenecks might occur, and describe how this might happen.

4. How can a devastating fire be a natural part of a biome’s dynamics? Give an example of a biome in which fires occur regularly?

5. Some scientists are currently attempting to catalog all of the world’s biodiversity. What are some of the technical problems they may encounter?

Additional Questions and Terms

1. What does the plant Atriplex have in common with the plants of a mangrove swamp?

2. The central Himalayan forest is a biome not discussed in this chapter. It stretches from about 25o to 35o north latitude, with annual precipitation of 50 to 350 centimeters, and a mean annual temperature of 54o F to 63 o F (12o to 17o C). This biome stretches over a million square kilometers and includes mountains, valleys, and plains. From June to September it is a monsoon season of warm torrential rains, which follows a warm and dry pre-monsoon season. At other times, the forest often experiences drought. Leaf litter is abundant, like in the tropics, and decomposes quickly, adding rich nutrients to the soil. What adaptations would enable organisms to live in this forest?

3. Why would cutting down the trees of mangrove swamp drastically alter the area?

4. Why are tundra and coral reefs very fragile ecosystems?

5. Would a highly polluted and stagnant lake be oligotrophic or eutrophic?