Exam 5: Environmental Systems and Ecosystem Ecology

Give a brief overview of the carbon cycle. Include the source of carbon that enters ecosystems, how it moves through ecosystems, what it is used for, and where it is ultimately deposited. What part of this cycle is believed to contribute to global warming?

The majority of Earth's fresh water exists _______________

The process by which water moves from Earth's surface (such as in lakes or rivers)to the atmosphere

The largest pool of carbon in the carbon cycle is _______________

Water returns from the clouds to Earth's surface as this

The solid earth beneath our feet

Aquifers are _______________

What are Earth's structural spheres?

Humans have dramatically altered the rate of nitrogen fixation into forms usable by autotrophs _______________

In an aquatic ecosystem experiencing eutrophication, levels of dissolved macronutrients _______________ and dissolved oxygen levels _______________

Read the following scenario and answer the question below. In the early years of the 20th century there were lush stands of tall grasses in the valley on the east side of the Chiricahua Mountains in Arizona, stretching to Mexico on the south and New Mexico on the east. Dramatic summer rainstorms dumped huge amounts of water, very quickly, on the rocky upper slopes. The water ran down the slopes and into the grasslands, where it quickly soaked into the soft, porous soil where prairie dogs were active. Cattle ranching was in full swing, utilizing the rich grasses, but the ranchers did not appreciate the multitudes of prairie dogs that lived in the grasslands. Prairie dogs constantly dig through soil, making new burrows and eating grasses, roots and all. It was commonly believed that cattle would stumble in the prairie dog holes, break legs, and die of starvation. In addition, many ranchers were convinced that the prairie dogs would destroy the grasses because they directly competed with the cattle for food. The ranchers had already done away with most predators that might possibly affect cattle, and now they turned their attention to the prairie dogs. The ranchers became a part of a new federally sponsored movement to poison the grassland prairie dogs. This movement took root and spread through the 1920s and 1930s. -In a previous chapter you read about "keystone species." How do the prairie dogs in this story meet the definition of a keystone species?

The phosphorus in all biological tissues can traced back to _______________

Ecological modeling can help us _______________ ecosystem services.

The first essential step in changing atmospheric nitrogen into more usable NH₃ is called _______________

Release of water vapor by plants through their leaves

Use the accompanying figure to answer the following questions. -This graph helps to explain _______________

Prairie dog activities probably contribute to _______________

Human activity has affected every aspect of the nitrogen cycle. List the ways that humans have altered nitrogen content starting with how nitrogen becomes available to producers, where it goes, and what impacts it has. What are the ecological concerns regarding the dramatic changes people have made in the global nitrogen cycle?

Define the term emergent properties and give an example from a natural system.

What factors contribute to the "dead zone" in Chesapeake Bay?