Ecology

1. From the BBC video on mycorrhizal fungi, when an older tree is about to die, what is one of the interesting ways it might respond through its mycorrhizal web?
2. The mycorrhizae may sense that the host tree is dying and uptake the resources for themselves.
3. It might dump its resources to neighboring related trees to help them survive.
4. It might feed on neighboring trees taking resources from them to increase its own survival.
5. The mycorrhizae can sense that the host tree is dying and switch to a new host.

2. Where does phosphorus originate in the phosphorus cycle?
3. rocks containing phosphate
4. ocean sediments
5. aqueous phosphate
6. the atmosphere
7. wastewater

3. Dead zones are formed when rivers that empty into oceans carry excess phosphorus and nitrate runoff. These dead zones are caused by
4. precipitates of nitrate and phosphorus forming in the water.
5. bacterial blooms.
6. algal blooms.
7. increased acidity due to nitrates and phosphorus.
8. nitrate and phosphorus poisoning.

4. What is the main avenue by which phosphorus returns to the ocean?
5. surface runoff
6. dust
7. dissolved in rainwater
8. wastewater

5. How do terrestrial ecosystems replace nongaseous nutrients lost to leaching and runoff?
6. weathering of bedrock
7. decomposition of organic matter
8. precipitation
9. atmospheric fixation

Short answer questions:

1. The above ground structures of mycorrhizal fungi are called ____________
2. What is the root-like structure of mycorrhizal fungi that gathers water and nutrients?
3. How does phosphorus lead to eutrophication of aquatic ecosystems?