Exam 15: Conserving Biodiversity: Community and Ecosystem Ecology

The entire species of North American right whales currently consists of less than 400 individuals. Through genetic testing, it has been determined that at some point in the past, probably around the time they were first protected in the beginning of the 20th century, the population had only three reproducing females. All individuals that exist today are thought to be descendants of those females. As a result, this species is vulnerable because of

Ants from the genus Pseudomyrmex live in bull's horn acacia trees, Acacia cornigera. The ants will attack any predators of the tree. In return, the ants live protected in the thorns of the tree and eat the nectar and protein-rich secretions of the tree. This is an example of

-According to this graph, when did the extinction rate in mammals exceed that of birds, if at all?

During the 1980s, wolves were reintroduced to Yellowstone National Park after decades of absence due to attempted extermination in the early part of the 20th century. Within 20 years, not only had the wolf population increased, but there was also a dramatic increase in other species, such as aspen, cottonwood, and willow trees, beavers, warblers, insects, and fish. These changes in Yellowstone Park are examples of how important a(n)________ can be to an ecosystem.

Life on Earth has experienced several mass extinctions. One or more of these extinctions was most likely caused by

The U.S. Endangered Species Act that mandates decisions about the management of endangered species can be based on

The current rapid loss of species is considered by many scientists to be another mass extinction. This increase in extinction rate, beyond background extinction, is thought to be due to

Scientists have used the fossil record to estimate the average length of time that a species inhabits the Earth. This estimate is useful for assessing the impact of humans on the Earth's biological diversity because it can

Teosinte is a wild grass in Mexico from which corn (maize)was originally domesticated. Corn that is grown commercially is probably

During the last decade, the U.S. Fish and Wildlife Service has worked to reestablish the critically endangered California condor in its last stronghold, the mountains of southern California. Recently, the service has also tried to establish a second population in the Grand Canyon region of Arizona. Why would the Fish and Wildlife Service consider it a high priority to establish two populations that are geographically distant from each other?

Which of the following is an example of a nearly extinct animal in the United States?

-According to this species-area curve for reptiles and amphibians on a West Indian archipelago, a 50% decrease in area will change the number of species living in the remaining area by

The greater fitness of individuals who carry one copy of the sickle-cell allele in areas where malaria is common is called

North America is currently experiencing an unprecedented and rapid loss of species. What is believed to be the main trigger of such events, either directly or indirectly?

Which group of organisms has the greatest percentage of species in danger of extinction, according to the IUCN?

The role a species plays in an ecosystem is called its

There is an article in your local newspaper about an upcoming "Biodiversity Day" event at your university. Because you understand why it's important to conserve biodiversity after studying biology, you plan to attend. Your younger brother tells you he doesn't understand how the loss of a few species or habitats in town can have any impact on anyone's life. You could tell him

A population of snakes lives in a valley. This population of snakes is 30% black and 70% brown in coloration. A dam is built to flood part of the valley, separating the snakes into two populations. West of the human-made lake, there's a very small population of all black snakes, while east of the lake, the population is much larger and retains the same percentage of black and brown coloration as before the dam was built. This is an example of

Many species have innate preferences for the habitat to which they're most adapted. These species show signs of stress when placed in a habitat different from that in which they naturally occur. Is there any evidence that humans might have innate habitat preferences that match the environment in which humans evolved?

Which of the following presents the greatest threat to biodiversity?