Exam 29: Energy Flow and Nutrient Cycling in Ecosystems

Each summer, a large ʺdead zoneʺ devoid of fish and other animals develops where the Mississippi River flows into the Gulf of Mexico. What causes this?

If you are attempting to minimize the amount of mercury in your diet, you should eat

Organisms that produce their own food from inorganic compounds through reactions powered by sunlight are heterotrophs.

Deforestation decreases the levels of greenhouse gases in the atmosphere.

Plants absorb small amounts of carbon from the soil in the form of simple sugars or monosaccharides.

Detritus feeders remove nutrients from the food chain.

What would happen in an ecosystem without decomposers and detritus feeders?

A snake that eats a small rabbit that feeds on grass is classified as a(n)

When nitrogen oxides and sulfur dioxide combine with water vapor in the air, they are converted to nitric acid and sulfuric acid, respectively. This precipitation that then falls to the Earth is known as

The global hydrologic cycle begins with precipitation falling to Earth, and the cycle is completed by __________, driven by solar energy.

Which of the following terms correctly describes carnivores?

The photosynthetic bacteria that form the basis of the food chain in the Great Salt Lake are classified as

Tropical rain forests are near the equator; they stay warm all year and have high annual precipitation. Northern coniferous forests have four seasons and most of the precipitation falls during winter and spring. Which of these ecosystems would you expect to be more productive? Explain why.

The__________ are an important and often overlooked group of organisms that release nutrients into the soil or water.

Plants produce biomass by taking in energy, CO 2, and nutrients from the environment; consumers eat much of this biomass, but not all. However, ecosystems do not indefinitely accumulate large quantities of organic matter over time. Why not?

Once used by an organism, carbon- and nitrogen-based nutrients are unavailable for other organisms.

Explain how the worldʹs food supply may be affected by whether people eat primarily meat or vegetables.

Why is phosphorus so important to living organisms?

On a field trip with your class to mountain lakes in Vermont, you come across a beautiful clear lake that is deep, and you can see the pebbles at its bottom. Why does your classmate hypothesize that this lake has been subjected to acidic deposition?

If a couple was attempting to get pregnant, which foods should they eat to avoid ingesting high amounts of toxins?