A species that occurs naturally in only one geographic area, such as a salamander found in a single spring, is described as what kind of species?
Endemic
✓
Invasive
Keystone
Exotic
Correct Answer
Endemic
An endemic species lives naturally in only one place, which makes species with tiny ranges especially vulnerable to local habitat damage. Invasive describes an introduced species that spreads and harms natives. Keystone describes a species whose removal collapses community diversity. Exotic describes a species moved by humans into a region where it did not evolve.
Category: Types and Patterns
Question 2
Across almost every group of organisms, species diversity tends to increase toward which part of the globe?
The poles
The equator
✓
The temperate mid-latitudes
The subarctic zone
Correct Answer
The equator
Biodiversity rises toward the equator in nearly every taxonomic group, a pattern called the latitudinal gradient. Proposed explanations include the greater age and stability of tropical ecosystems and the greater solar energy they receive. The poles have the fewest species. The temperate mid-latitudes are less diverse than the tropics. The subarctic zone is among the least diverse regions.
Category: Types and Patterns
Question 3
Forest A and Forest B contain the same 10 tree species. In Forest A each species makes up 10 percent of the trees, while in Forest B one species makes up 91 percent and each of the others makes up 1 percent. Which statement is accurate?
Forest B is more diverse
Both forests are equally diverse
Forest A is more diverse
✓
Diversity cannot be compared here
Correct Answer
Forest A is more diverse
Diversity depends on relative abundance as well as on the number of species, so a community where species are evenly common is more diverse than one dominated by a single species. Forest B is more diverse is wrong because one species overwhelms the rest. Both forests are equally diverse ignores relative abundance. Diversity cannot be compared here is wrong because the abundance data allow a direct comparison.
Category: Types and Patterns
Question 4
The drug vincristine, obtained from the Madagascar periwinkle, is used to treat which diseases?
High blood pressure and angina
Malaria and dengue fever
Bacterial pneumonia and sepsis
Leukemia and lymphoma
✓
Correct Answer
Leukemia and lymphoma
Vincristine is a plant-derived chemotherapy drug used against blood cancers such as childhood leukemia and lymphomas, showing how wild plants can supply valuable medicines. High blood pressure and angina are treated with heart and blood pressure drugs, not vincristine. Malaria and dengue fever are not treated with periwinkle compounds; malaria was historically treated with quinine from cinchona bark. Bacterial pneumonia and sepsis are treated with antibiotics, which come mostly from fungi and bacteria.
Category: Value to Humans
Question 5
The Irish potato famine of 1845 to 1852 illustrates the danger of which agricultural practice?
Relying on a single crop variety
✓
Overusing chemical fertilizers
Clearing forests for new fields
Irrigating crops with salty water
Correct Answer
Relying on a single crop variety
Ireland depended heavily on a genetically uniform potato variety, so when blight struck, nearly the whole crop was susceptible and failed. Overusing chemical fertilizers did not cause the famine. Clearing forests for new fields was not the cause of the crop failure. Irrigating crops with salty water played no role in the blight outbreak.
Category: Value to Humans
Question 6
What is the main purpose of the Svalbard Global Seed Vault in arctic Norway?
Breeding endangered arctic mammals
Backing up crop seed collections
✓
Storing frozen embryos of zoo animals
Monitoring the melting of sea ice
Correct Answer
Backing up crop seed collections
The vault stores duplicate seed samples as a backup for seed banks around the world, preserving crop genetic diversity in cold, stable rock. Breeding endangered arctic mammals is a captive breeding goal, not the vault's role. Storing frozen embryos of zoo animals is done by frozen zoo programs, not this seed vault. Monitoring the melting of sea ice is climate research, not the vault's purpose.
Category: Value to Humans
Question 7
Honeybees and many other insects provide which ecosystem service that many fruit, vegetable and nut crops depend on?
Nitrogen fixation
Water filtration
Pollination
✓
Decomposition
Correct Answer
Pollination
Pollination is the transfer of pollen that lets many flowering crops set fruit and seed, and insect pollinators are worth billions of dollars a year to U.S. agriculture. Nitrogen fixation is carried out by certain bacteria, not by bees. Water filtration is performed by soils and wetlands. Decomposition is carried out mainly by bacteria, fungi and other soil organisms.
Category: Value to Humans
Question 8
Orangutans on Borneo are threatened as rainforest is cleared for timber and palm oil plantations. Which threat to biodiversity does this represent?
Overharvesting
Exotic species
Toxic pollution
Habitat loss
✓
Correct Answer
Habitat loss
Clearing forest removes the habitat orangutans and thousands of other species need, which is habitat loss, one of the greatest threats to biodiversity. Overharvesting means taking individuals faster than populations can recover, as in overfishing. Exotic species are organisms introduced by humans into new ecosystems. Toxic pollution harms specific species but is not what clearing forest for plantations does.
Category: Major Threats
Question 9
When individuals overuse an open-access resource they do not own, such as an ocean fishery, because each gains by taking more, the result is called what?
Tragedy of the commons
✓
Founder effect
Competitive exclusion
Extinction debt
Correct Answer
Tragedy of the commons
The tragedy of the commons describes how users of a shared resource have little incentive to restrain their own harvest, so the resource is depleted. The founder effect is a loss of genetic variation when a few individuals start a new population. Competitive exclusion is when one species outcompetes another for the same niche. Extinction debt refers to species that are doomed to vanish after habitat loss but have not yet died out.
Category: Major Threats
Question 10
As the global climate warms, climate zones and the species ranges that track them are generally shifting in which direction?
Toward the equator
Toward the poles
✓
Down to lower elevations
Westward across continents
Correct Answer
Toward the poles
Warming moves suitable climates toward the poles and up mountainsides, and the ranges of many birds, butterflies and plants are already shifting poleward. Toward the equator is the opposite of the observed pattern. Down to lower elevations is wrong because mountain climate zones are moving upslope. Westward across continents is not a general pattern caused by warming.
Category: Major Threats
Question 11
Which introduced predator, accidentally carried to Guam in cargo after World War II, wiped out several of the island's native forest birds?
Cane toad
Burmese python
Brown tree snake
✓
Small Indian mongoose
Correct Answer
Brown tree snake
The brown tree snake arrived on Guam as a stowaway and, with no natural predators there, drove several bird and reptile species found only on Guam to extinction. Cane toad is a well-known invader of Australia, not the cause of Guam's bird losses. Burmese python is an invader of the Florida Everglades. Small Indian mongoose was introduced to islands such as Hawaii, not the predator behind Guam's extinctions.
Category: Exotic Species
Question 12
Lake Victoria's cichlid fishes declined drastically after the intentional introduction of which large predatory fish?
Common carp
Rainbow trout
Largemouth bass
Nile perch
✓
Correct Answer
Nile perch
The Nile perch was stocked in Lake Victoria for fishing and is largely blamed for the extinction of a large share of the lake's endemic cichlid species. Common carp is a widespread invader elsewhere but is not linked to the Lake Victoria losses. Rainbow trout is a cold-water fish not responsible for the collapse. Largemouth bass is a North American predator not tied to Lake Victoria's cichlid extinctions.
Category: Exotic Species
Question 13
By what route did zebra mussels reach the North American Great Lakes from Europe?
In ship ballast water
✓
Through aquarium releases
Through stocking for food
On migrating waterfowl
Correct Answer
In ship ballast water
Ships take on water for stability at one port and discharge it at another, releasing larvae and other organisms, and this is how zebra mussels arrived in the Great Lakes. Through aquarium releases is a route for some invaders but not for zebra mussels. Through stocking for food was not how they arrived, since zebra mussels were never stocked. On migrating waterfowl is not the documented route of their introduction.
Category: Exotic Species
Question 14
The fungal disease chytridiomycosis is linked to severe population declines worldwide in which group of animals?
Bats
Amphibians
✓
Coral polyps
Songbirds
Correct Answer
Amphibians
Chytridiomycosis, caused by a chytrid fungus, infects the skin of frogs and other amphibians and has been tied to a global amphibian decline. Bats are being killed by a different fungal disease, white-nose syndrome. Coral polyps are threatened by ocean warming and bleaching. Songbirds are not the group affected by chytrid fungus.
Category: Exotic Species
Question 15
The mass extinction that ended the age of the non-avian dinosaurs is widely attributed to which event?
A sudden ice age
A global disease outbreak
A large asteroid impact
✓
The rise of flowering plants
Correct Answer
A large asteroid impact
Most scientists attribute this extinction to a large asteroid striking the area of today's Yucatan Peninsula, followed by dust and climate disruption. A sudden ice age is not the accepted cause. A global disease outbreak has no supporting evidence as the cause. The rise of flowering plants happened over millions of years and did not cause the sudden extinction.
Category: Extinction Through Time
Question 16
The background extinction rate is about 1 extinction per million species per year. If Earth has 10 million species, about how many species would be expected to go extinct each year at the background rate?
1
100
1,000
10
✓
Correct Answer
10
Ten million species is 10 groups of one million, and each group loses about 1 species per year, so about 10 extinctions per year are expected. 1 results from forgetting to scale up from one million to ten million species. 100 is ten times too high. 1,000 is a hundred times too high and is closer to some estimates of today's accelerated rate.
Category: Extinction Through Time
Question 17
Which international agreement restricts cross-border trade in listed endangered plants and animals and products made from them?
CITES
✓
Kyoto Protocol
Montreal Protocol
Ramsar Convention
Correct Answer
CITES
CITES, the Convention on International Trade in Endangered Species, controls international trade in tens of thousands of listed species. Kyoto Protocol set targets for greenhouse gas emissions. Montreal Protocol phased out chemicals that deplete the ozone layer. Ramsar Convention protects wetlands of international importance.
Category: Conservation Strategies
Question 18
Which U.S. law, passed in 1973, requires the government to protect listed threatened and endangered species and plan for their recovery?
Clean Water Act
Endangered Species Act
✓
Lacey Act
Wilderness Act
Correct Answer
Endangered Species Act
The Endangered Species Act of 1973 protects listed species and requires recovery plans, though critics note it often focuses on single species rather than whole ecosystems. Clean Water Act regulates pollution in U.S. waters. Lacey Act, passed in 1900, bans trade in illegally taken wildlife and plants. Wilderness Act, passed in 1964, protects designated wild lands.
Category: Conservation Strategies
Question 19
To be named a biodiversity hotspot, a region must hold many plant species found nowhere else and must also meet which condition?
It is already a protected preserve
It has never been settled by humans
It has lost most of its original habitat
✓
It is free of exotic species
Correct Answer
It has lost most of its original habitat
Hotspots combine high numbers of endemic plants with heavy human disturbance, originally defined as having lost at least 70 percent of their original habitat, so they mark places where conservation is most urgent. It is already a protected preserve is not a criterion. It has never been settled by humans is the opposite of the requirement. It is free of exotic species is not part of the definition.
Category: Conservation Strategies
Question 20
A species whose removal causes a sharp drop in a community's diversity, as with the gray wolf in Yellowstone, is called what?
Pioneer species
Indicator species
Endemic species
Keystone species
✓
Correct Answer
Keystone species
A keystone species has an effect on its community far out of proportion to its numbers, and returning wolves to Yellowstone restored streamside plants and many other species. Pioneer species are the first to colonize bare ground during succession. Indicator species reveal environmental conditions such as pollution. Endemic species are found in only one place.
Category: Conservation Strategies