Exam 58: A Changing Biosphere

Of 85 invasive species entering the Great Lakes through the St.Lawrence Seaway, 54 have been linked to transport in and discharge from ships' ballast water.Included are the zebra mussel and the quagga mussel.This information suggests that the spread of invasive species in ballast water

Because giraffes are large and relatively friendly, they are still often seen on safaris, but conservationists say they are undergoing a "silent extinction." A recent study shows that giraffe populations have declined by at least 30 percent over the last 30 years (three giraffe generations).Due to their declining effective population size, giraffes in the coming years could show which change in population dynamics?

North America's largest flying bird, the California condor, survives today because of a preservation program called _______.

A person living in a small town has a large backyard in which she cultivates a vegetable garden and several flower gardens.She plants flowering shrubs, hangs birdhouses, and sets up a birdbath.She provides habitat for butterflies and other pollinators, and for toads and other insect predators.The resulting backyard can best be described as a

One strategy considered for preventing introduction of invasive species is deoxygenating ballast water.This strategy is

Coral reefs destroyed by dynamite fishing or other destructive practices are sometimes restored by building metal lattices, or "spiders," and attaching them to the seafloor.Pieces of living coral are attached to the lattices and eventually reproduce and grow, gradually increasing the size of the coral skeleton and restoring the coral reef habitat.In this situation, the ecological restoration process is aided by the use of a(n)

Refer to the graph. "Collapsed" fish taxa are species or groups of species that have declined to less than 10 percent of the biomass they had before they were fished.These low numbers represent commercial extinction, or levels too low to produce a profit when those taxa are fished.Changes in the numbers of collapsed taxa since 1950 are shown in the graph.The trend shown indicates that

A researcher is very concerned about organism extinctions and wants to address this problem by developing new methods for tracking and predicting extinctions.She develops a list of potential programs that might be implemented.Which new potential program would probably be most practical and most helpful in predicting extinctions?

Elevated atmospheric CO₂ concentration results in higher rates of plant photosynthesis.It also increases the plants' carbon-to-nitrogen ratio, causing a "nitrogen dilution" effect that decreases leaf protein levels and nutritional content.Herbivorous insects in elevated CO₂ conditions show a 22 percent decline in abundance, 17 percent increase in consumption rates, 4 percent increase in development time, 9 percent decrease in relative growth rate, and 5 percent decrease in pupa weight.These are average changes that vary by species and are most pronounced for chewing insects.These changes suggest that climate-induced increases in CO₂ levels will likely have

Costa Rica protects the country's high level of biodiversity by offering environmentally sensitive hiking and bird-watching trips to protected national parks.This maintenance of a noneconomic value (biodiversity) by the use of an economic-based industry is known as _______.

Emergence of a new endemic pathogen in an ecosystem (as opposed to a newly introduced pathogen) is most likely to occur by which method?

Ecologically, if an area cannot support viable populations of a species or it lacks its original ecosystem services and functions, it does not meet the qualifications to be considered a _______.

Ballast water from ships has been responsible for the intercontinental spread of a number of invasive species.One promising strategy proposed by conservationists to reduce this danger is to

Refer to the table. According to the table, do ocean organisms show the same general trends in response to climate change as are shown by terrestrial organisms?

Refer to the table. According to the table, the trend for land-based organisms as air temperatures increase is for

In Gabon, West Africa, the Wotango tree is harvested for its medicinal bark.The bark's chemical cannot be synthesized in the lab; it must be obtained from the bark itself.Before 1985, a French pharmaceutical company owned the rights to the chemical and harvested the tree sustainably.In 1985, the company began granting harvesting licenses to local businesses.Now, harvesting is described as "out of control," because villagers need the income.What does this information suggest about the current and future status of the Wotango tree?

What are nonmarket, or noneconomic, values of biodiversity? Give examples of these, and justify the importance of preserving biodiversity for these noneconomic values.

Aquatic species, such as ocean fish, are particularly vulnerable to overharvesting due to a concept called "tragedy of the commons." When everyone harvests a shared (common) resource, each person tends to harvest as much as possible, because no one owns the resource and there is no motivation to be restrained.This is a particular problem now, with the growing human population and constantly improving technology that makes harvesting fast and efficient.In this situation, which type of fish species would likely be most vulnerable to extinction?

Refer to the graph. The graph shows the breakdown by extinction risk category of the species assessed by the International Union for Conservation of Nature (IUCN).Based on the graph, what percentage of species in the world are considered threatened?

According to the categories set by the International Union for Conservation of Nature (IUCN), the species most highly threatened by extinction are classified as _______.