Question 1

The variety of species in an area of interest is called
A) biomass.
B) biodiversity.
C) the trophic pyramid.
D) the ecological niche.

Accepted Answer

Biodiversity refers to the variety of species in a particular area or ecosystem. Biomass refers to the total mass of living organisms within an area, the trophic pyramid refers to the hierarchy of energy flow in an ecosystem, and the ecological niche refers to the specific role and habitat of a particular species within an ecosystem.

Question 2

The North Atlantic Right Whale, Eubalaena glacialis, was called the "right whale" because they were the best whale for early whalers to kill. They have long baleen and lots of blubber and oil. When killed, they could be towed back to land for processing because they float. They once numbered in the millions, but the entire population of the species is now less than 400. The history of the right whale is an example of
A) pollution.
B) overexploitation.
C) habitat destruction.
D) competition.

Accepted Answer

The history of the North Atlantic Right Whale is an example of overexploitation, as they were heavily hunted by whalers for their baleen, blubber, and oil. This led to a significant decline in their population, and they are now classified as endangered. While pollution and habitat destruction can also impact whale populations, these factors were not the primary cause for the decline of the North Atlantic right whale. Competition might be a factor in some situations, but it is not relevant to the history of this particular species.

Question 3

What law was passed to address the problem of rapid species loss in the United States?
A) the Endangered Species Act of 1973
B) the Wilson-Biophilia Act of 1994
C) the Biodiversity Act of 1975
D) the Human Intervention Act of 1979

Accepted Answer

This law provides protections for threatened and endangered species and their habitats, and has been instrumental in preventing many species from going extinct in the United States. It has also spurred conservation efforts and research into endangered species. The other options listed are not real laws.

Question 4

The estimated 10 million species that exist today are thought to represent approximately ________ of the species that have ever existed on Earth.
A) 80%
B) 10%
C) 1%
D) 0.0001%

Accepted Answer

It is estimated that over 99% of all species that have ever existed on Earth are now extinct, meaning the currently known 10 million species represent only around 1% of the total number of species that have ever lived.

Question 5

How does the rate of extinction today compare to the rates in the past?
A) The rate is much lower today than it has been, on average, in the past.
B) The rate is about the same today as it has been, on average, in the past.
C) The rate is much higher today than it has been, on average, in the past.
D) The extinction rate today can't be estimated or calculated.

Accepted Answer

The current rate of extinction is estimated to be 100 to 1,000 times higher than the natural background extinction rate, which is much higher than the rates seen in the past. This is largely due to human activities such as habitat destruction, pollution, and climate change.

Question 6

The current rate of extinction is estimated to be ________ times greater than the calculated background rate.
A) 100
B) 50
C) 10
D) 2

Accepted Answer

The current rate of extinction is estimated to be about 100 times greater than the natural background rate due to human activities.

Question 7

Fenway Park, home of the Boston Red Sox, is situated on land that was once a fen, a kind of wetland. The replacement of the fen is an example of
A) pollution.
B) overexploitation.
C) habitat destruction.
D) competition.

Accepted Answer

Fenway Park's construction and maintenance involved the destruction of the fen wetland habitat.

Question 8

Which of the following is an example of a nearly extinct animal in the United States?
A) black-footed ferret
B) mourning dove
C) striped skunk
D) coyote

Accepted Answer

Black-footed ferrets were once thought to be extinct, but a small number have been reintroduced into the wild. They are still considered a nearly extinct animal in the US. The other choices (mourning dove, striped skunk, and coyote) are not considered nearly extinct.

Question 9

What is the estimated "background rate" of extinction, as calculated by scientists?
A) 10% per year
B) 1% per year
C) 0.1% per year
D) 0.0001% per year

Accepted Answer

The estimated background rate of extinction, as calculated by scientists, is about 0.0001% per year. This rate represents the natural rate of species extinction in the absence of human influence.

Question 10

Although most biologists believe that many species are becoming extinct each year because of the activities of humans, relatively few species actually appear on compiled lists of extinct species. What is one reason why so few species are listed as extinct?
A) Many species are unknown to science and go extinct before they've been described.
B) There really aren't that many species that have become extinct.
C) Many species aren't listed because they aren't considered important.
D) Only extinctions that are naturally caused are listed.

Accepted Answer

Many species that become extinct are unknown to science and therefore not included on lists of extinct species. By the time they are discovered and described, they are already gone.

Question 11

There have been ________ mass extinctions experienced on a global scale before the alarming mass extinction that's now occurring.
A) six
B) five
C) two
D) no

Accepted Answer

According to scientific research, there have been five mass extinctions in the past.

Question 12

Purple loosestrife, Lythrum salicaria, is a beautiful, long-stemmed wetlands species brought to the United States from Europe as an ornamental plant. In the United States, it has no predators and crowds out cattails, Typha latifolia, another wetlands plant that's a valuable resource for many species. Purple loosestrife is an example of
A) an introduced species.
B) a parasite.
C) a predator.
D) overexploitation

Accepted Answer

Purple loosestrife is an introduced species, meaning it was brought to the United States from its native range and introduced to a new environment where it has no natural predators or controls. As a result, it can become invasive and outcompete native species, like cattails.

Question 13

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
A) help determine how long the human species might survive.
B) determine which species might become extinct soon, even if humans aren't involved.
C) estimate how many species extinctions are caused by human activity.
D) assure us that human activity is not the cause of most species extinctions.

Accepted Answer

By estimating the average length of time a species inhabits the Earth, scientists can compare it to the current extinction rates and determine how many of these extinctions are likely caused by human activity. This information can help us understand the impact of humans on biological diversity and make informed conservation decisions. Option A and D are not supported by the information given, and option B is partially correct but does not fully capture the usefulness of the estimate.

Question 14

How many species "normally" go extinct each year, as estimated by scientists?
A) 1 species per thousand per year
B) 1 species per million per year
C) 1 species per billion per year
D) 1 species per year

Accepted Answer

The answer of How many species "normally" go extinct each...

Question 15

Global climate change is likely to increase the rate of extinction worldwide. The pollutant most implicated in this problem is
A) nitrous oxides.
B) carbon dioxide.
C) sulfur dioxides.
D) chlorofluorocarbons.

Accepted Answer

Carbon dioxide is the most common greenhouse gas emitted by human activities and is considered the main pollutant responsible for global climate change. As temperatures increase, many species may not be able to adapt fast enough, leading to increased extinction rates.

Question 16

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
A) a recent increase in earthquakes worldwide.
B) human population growth and the resulting habitat changes worldwide.
C) global climate change.
D) changes in the number of solar flares observed recently.

Accepted Answer

The current rapid loss of species is mainly due to human activities such as deforestation, pollution, overfishing, hunting, and climate change resulting in habitat destruction, fragmentation, degradation, and alteration. Earthquakes, solar flares, and other natural phenomena can impact biodiversity but are not the primary cause of the current mass extinction.

Question 17

Approximately 200 of the 300 native species of fish in Lake Victoria haven't been observed since the 1960s and are therefore probably extinct. Using the estimate of the background extinction rate, how many species of Lake Victoria fish would one expect to have naturally become extinct during the last 50 years?
A) less than 1
B) 1-10
C) 11-50
D) more than 50

Accepted Answer

The background extinction rate is the rate at which species would become extinct without human intervention or other major disturbances to the environment. This rate is estimated to be 0.1-1 extinction per million species per year. With about 300 species of fish in Lake Victoria, we would expect 0.03-0.3 extinctions per year due to natural causes. Over a period of 50 years, we would expect about 1-15 extinctions. Therefore, it is reasonable to conclude that less than 1 species of Lake Victoria fish would naturally become extinct during the last 50 years. The fact that approximately 200 species are believed to be extinct suggests that human activities, such as introduction of non-native species, overfishing, pollution, and habitat destruction, have had a significant impact on the fish populations in the lake.

Question 18

In order to be considered extinct, a species can't be found
A) at all, in the wild or in captivity at the present time.
B) at all, presently or during the past 10 years.
C) at all, presently or during the past 50 years.
D) in the wild presently but may exist in captivity.

Accepted Answer

The answer of In order to be considered extinct, a...

Question 19

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?
A) continental drift
B) increased human population
C) climate change
D) increased predation by wild carnivores

Accepted Answer

The increased human population has led to habitat destruction, fragmentation, and pollution which are direct drivers of species loss in North America.

Question 20

Life on Earth has experienced several mass extinctions. One or more of these extinctions was most likely caused by
A) an asteroid impact.
B) worldwide drought.
C) genetic drift.
D) an increase in large predatory mammals.

Accepted Answer

The most widely accepted theory for one of Earth's mass extinctions is an asteroid impact, specifically the Chicxulub impact that occurred about 66 million years ago and is believed to have caused the extinction of the dinosaurs.

Quiz 15: Conserving Biodiversity: Community and Ecosystem Ecology

The variety of species in an area of interest is called

What law was passed to address the problem of rapid species loss in the United States?

The estimated 10 million species that exist today are thought to represent approximately ________ of the species that have ever existed on Earth.

How does the rate of extinction today compare to the rates in the past?

The current rate of extinction is estimated to be ________ times greater than the calculated background rate.

Fenway Park, home of the Boston Red Sox, is situated on land that was once a fen, a kind of wetland. The replacement of the fen is an example of

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

What is the estimated "background rate" of extinction, as calculated by scientists?

Although most biologists believe that many species are becoming extinct each year because of the activities of humans, relatively few species actually appear on compiled lists of extinct species. What is one reason why so few species are listed as extinct?

There have been ________ mass extinctions experienced on a global scale before the alarming mass extinction that's now occurring.

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

How many species "normally" go extinct each year, as estimated by scientists?

Global climate change is likely to increase the rate of extinction worldwide. The pollutant most implicated in this problem is

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

In order to be considered extinct, a species can't be found

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?

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