Exam 58: A Changing Biosphere

As sea levels rise because of climate change, some shallow-water marine ecosystems such as coral reefs and seagrass beds will be located in deeper water.What effect will the deeper water likely have on these ecosystems?

In tropical regions such as Malaysia and Indonesia, huge swaths of rainforest are cut and replaced with palm oil plantations.Species such as orangutans, tigers, elephants, and rhinoceroses are isolated, and their sources of food and shelter are declining.The best description of the pressure on biodiversity in this situation is _______.

In the nineteenth and early twentieth centuries, the major cause of species extinction was _______.

When protected areas or restored ecosystems are too small, they are unable to restore the high diversity present in the original ecosystem.One example of this is seen in the remnants of the tallgrass prairies, which once supported massive herds of bison, elk, deer, pronghorn, and their predators.Now, these massive herds have been reduced to very small populations.When populations reach such low numbers, they become difficult to maintain because of their lack of

Twenty-eight species of migratory birds on the East Coast are nesting earlier than they did 50 years ago.This piece of evidence is associated with which type of response of organisms to climate change?

A protected area is designed to meet all of the following criteria except that it

Prairie potholes are small, shallow lakes in the north-central United States that are essential breeding habitat for most species of North American waterfowl and for many amphibians.Climate change is making this region warmer and drier, causing many prairie potholes to dry up and disappear.How will this change in the environment most likely affect future waterfowl and amphibian populations in the region?

Consider species currently in the three "threatened" categories, as defined by IUCN.In what ways are humans responsible for these threats to species? Which of these threats are likely to increase in the future, and why?

Up to 90 percent of saltwater fish caught for the aquarium trade are captured by dousing coral reefs with sodium cyanide.Many fish die, but those that receive only low doses are temporarily incapacitated, so they are easily captured.The coral reef, which cannot swim away, receives most of the cyanide.Many corals and other reef animals die, and the cyanide effects ripple through the food web.This information suggests that cyanide is hazardous to

Due to melting polar ice and warming oceans, coastal ecosystems around the world are at risk from rising _______.

Which statement is both correct and supports ecologists' view that amphibian species extinctions are increasing?

In which of these situations was an organism introduced to a new environment but would likely not be considered an invasive species?

The Lord Howe Island stick insect was thought extinct about 1930, after introduced mice and rats eliminated it from the Australian island, its only known habitat.Then, in 2001, scientists found 24 individuals living under a single shrub on an extremely isolated islet in the Pacific.They produced about 1,000 adults and 20,000 eggs through captive breeding, and a captive colony was established on Lord Howe Island.The individuals cannot be released to their former habitat until the rodents have been eradicated, and the Australian government has now initiated a program to do this.The best conclusion that can be drawn from this story is that

After pumas were hunted to extinction in a region of North America, the deer population soared, leading to indirect effects on lower levels of the food web.This suggests that pumas were a keystone species and that their removal led to an interruption in the _______ of the ecosystem.

According to the International Union for Conservation of Nature (IUCN), the factor responsible for the most amphibian declines is

Blue whales, the world's largest animal, occur in all oceans except the Arctic.Before whaling, there were more than 250,000 blue whales.By 1967, when the species received worldwide protection, they were nearly all gone.Blue whale populations are recovering slowly compared with other whale species, such as humpbacks.This is most likely because

When populations become smaller and lack genetic diversity, they are more likely to become _______.

According to evolutionary biologist Edward O.Wilson, the world is currently losing approximately _______ species to extinction every year.

Poaching of endangered species such as rhinoceroses and elephants is an increasing problem.Poaching is one example of the type of biodiversity loss known as _______.

A species is highly endangered, with a very small breeding population in the wild and a polluted habitat.People interested in preventing the extinction of this species would most likely institute a(n)