Exam 29: Energy Flow and Nutrient Cycling in Ecosystems

In 1956, people in Minamata, Japan, began to exhibit severe neurological disorders and birth defects. This problem was eventually attributed to methylmercury, a water-insoluble and breakdown-resistant chemical formed from mercury dumped into the adjacent bay by a local factory. Which of the following types of seafood would have the highest levels of methylmercury, and therefore cause the severest effects?

One of the basic principles of ecosystems is that __________moves through the ecosystems in a continuous one-way flow.

The amount of energy captured by plants and made available to consumers in an ecosystem is called

What are the sources of sulfur in the atmosphere?

What proportion of the solar radiation that reaches Earthʹs surface is visible light?

In the __________cycle, water is cycled among the atmosphere, oceans, and living organisms.

What is meant by the term trophic level?

__________are organisms such as earthworms, millipedes, and other scavengers that eat waste products and dead organic matter.

Bacteria that live in deep-sea thermal vents use energy from inorganic hydrogen sulfide (H 2S) to make organic molecules from carbon dioxide and are thus

Plants often grow poorly in sterilized soils because the soils lack nitrogen-fixing bacteria.

The first trophic level of an ecosystem consists of

As part of a research project, a graduate student creates an artificial environment in a sealed container. She sterilizes the soil and adds plants, snails, shrews, and a snake. After adding a small artificial pond, she seals the container. During the first several weeks, the plants are thriving and the animals are doing well. However, piles of dropping are beginning to accumulate, and the entire floor of the container becomes covered with a layer of plant debris several inches thick. One probable cause for the problems is that the graduate student didnʹt

In open-water marine ecosystems, the__________ occupy the same trophic level as the giant sequoias (redwoods) in the forests of California.

__________is (are) a crucial nutrient reservoir of phosphorus that is available to organisms.

Iron is a limiting factor in many aquatic ecosystems. If the iron level is increased, the amount of phytoplankton (which feed on iron) decreases.

The global phosphorus cycle is called a ʺcycle,ʺ yet it has no atmospheric component. Phosphorus weathers from rocks and enters the soil. Once phosphorus is incorporated into plants or animals, how is it returned to the rock phase?

Nitrogen is the most abundant element in the atmosphere, and a crucial component of proteins, vitamins, and nucleic acids. However, plants and other producers cannot use nitrogen in its natural form (N₂). Nitrogen has to undergo a process called nitrogen fixation. What does this process involve?

In an attempt to become more environmentally conscious, a woman changes her lifestyle. She begins to grow the majority of her own food in her yard without using pesticides or synthetic fertilizers, she walks rather than taking the car for trips shorter than 5 kilometers, and she uses solar and wind for her power. By taking these actions, she is

There is a school of thought that encourages humans to give up eating meat and become herbivores. What are the advantages to this?

The primary reservoir for the nutrient__________ is rock.