Exam 20: Communities and Ecosystems

Movement corridors ________.

-Refer to the accompanying figure. Together, all of the living components of the coral reef represent a(n)________.

The organisms that can convert atmospheric nitrogen gas to a form that can be utilized by plants are ________.

A traveler was crossing the border from Canada to the United States and with a bag of Washington State apples. The customs officer at the border would not let the traveler take the apples into the United States, despite the apples originating from the United States. Why did the customs officer refuse to allow the traveler to cross the border with the apples?

Scenario In East Java, Indonesia, a mud volcano has been erupting since 2006. One controversial hypothesis is that the mud volcano in East Java is erupting because a gas mining company was drilling a deep hole nearby. When a mud volcano erupts, hot water deep below the earth's surface mixes with various minerals, and this mud spews out over the surface of the earth. The hot mud flow destroys organismal habitats, including the homes and livelihoods of people. -When the mud volcano stops erupting, the disturbed area will be colonized by a variety of species. This process of colonization is called ________.

Scenario Malaria is an infectious disease caused by a unicellular eukaryotic organism belonging to the genus Plasmodium. These eukaryotic organisms are transmitted from one person to another by the female Anopheles mosquito when it feeds on human blood. Within humans, the Plasmodium species destroy red blood cells and, without effective treatment, serious infections can lead to death. Currently, more than 400 million people are afflicted with malaria and between 1 and 3 million people die from it each year. Historically, a chemical compound called quinine has been used in developing effective drugs against malaria. In its natural environment, quinine is produced by certain trees native to South America. This chemical is synthesized in the outer layer of tree trunks and acts as an herbivore deterrent. -Despite being used for many years, quinine-based drugs have not led to the eradication of malaria and currently there are parasites that are resistant to the compound. What process was likely important in the development of this resistance to quinine?

In Yellowstone National Park, wolves were hunted to extinction in the 1920s. A current restoration project has reintroduced wolves to Yellowstone National Park. Predict the response of the Yellowstone ecological community if wolves are a keystone species.

If there were an additional trophic level in this figure that consisted of organisms that prey on snakes, about how much energy would be available to organisms at that trophic level?

This graph shows the results of a study on black-legged tick nymphs that are infected with the Lyme disease bacterium. The density of infected nymphs was calculated for forest fragments of different sizes (area in hectares). Answer the following questions using this graph. -Humans can be infected with the Lyme disease bacterium. According to the graph, a hiker has the highest risk of encountering an infected black-legged tick nymph in forests that are ________ in area.

-The figure shows the results of an experiment where sea stars were removed from communities. What is the sea star's role in the community?

In an aquatic food chain, small fishes that eat zooplankton are ________.

Species that require large areas to survive are disappearing as their habitat is destroyed. Researchers have found that increased forest fragmentation is associated with a higher risk of Lyme disease, which is carried by white-footed mice and transmitted from mice to humans by black-legged ticks. The researchers hypothesized that communities with higher biodiversity contain hosts for the Lyme disease bacteria that do not spread the bacteria to humans. Propose an alternative hypothesis that uses energy flows in ecosystems to explain their findings.

The rate at which an ecosystem's producers convert solar energy to chemical energy stored in biomass is called ________.

In order to assess the species diversity of a community, you would need to know the number of different species present as well as ________.

Scenario Malaria is an infectious disease caused by a unicellular eukaryotic organism belonging to the genus Plasmodium. These eukaryotic organisms are transmitted from one person to another by the female Anopheles mosquito when it feeds on human blood. Within humans, the Plasmodium species destroy red blood cells and, without effective treatment, serious infections can lead to death. Currently, more than 400 million people are afflicted with malaria and between 1 and 3 million people die from it each year. Historically, a chemical compound called quinine has been used in developing effective drugs against malaria. In its natural environment, quinine is produced by certain trees native to South America. This chemical is synthesized in the outer layer of tree trunks and acts as an herbivore deterrent. -Based on the relationship between Plasmodium spp. and humans, Plasmodium would be considered ________.

Approximately what percentage of the visible light that reaches Earth's producers is converted to chemical energy?

As a result of a severe disturbance, a community will ________.

-Examine the figure. Which statement correctly compares the biomass of different trophic levels to the concentrations of PCB contained in each level.

Organisms that consume producers are ________.

Bears eat berries, humans, and large fish; large fish eat smaller fish and insects; humans eat bears, large fish, and berries. The scenario described here is an example of ________.