Question 1

The most important threat to survival of polar bears at this time is

Accepted Answer

The warming of the Arctic has led to the shrinking of the winter ice pack which in turn has limited hunting opportunities for polar bears. This reduction in food sources threatens the survival of polar bears, making it the most important threat to their survival at present. While pollutants and hunting by native populations have been historically challenging to the polar bears' survival, the current critical threat is the rapidly changing climate. Tourism disruptions and normal population cycles are not significant factors affecting the survival of polar bears.

Question 2

_____ have estimated that up to 25% of the world's current animal and plant species could be gone by 2050, and 50% could be gone by the end of the century.

Accepted Answer

Edward O. Wilson and Stuart Pimm have estimated that up to 25% of the world's current animal and plant species could be gone by 2050, and 50% could be gone by the end of the century. The other options do not have any credible sources or evidence to suggest such estimates.

Question 3

An endangered species is any species that can

Accepted Answer

An endangered species is a species that is at risk of extinction in all or part of its range. Thus, option C is the best choice. Option A refers to genetic modification, which is not necessarily related to endangered species. Option B uses the term "rare," but being rare does not necessarily mean a species is endangered. Option D is partially correct, but it only describes a possible future outcome, rather than the current status of a species. Option E is incorrect because the economic importance of a species is not a determining factor in whether it is endangered or not.

Question 4

Wild species' instrumental value includes their use as

Accepted Answer

The answer of Wild species' instrumental value includes their use...

Question 5

The species area relationship concept suggests that if 90% of a coral reef is lost

Accepted Answer

The species-area relationship is a well-established ecological principle that suggests a logarithmic relationship between habitat area and species richness. A 90% loss in area typically results in a significant but not proportional loss of species, often around 50%.

Question 6

A biologist is most likely to say that the passenger pigeon is

Accepted Answer

The passenger pigeon is considered biologically extinct because there are no surviving individuals of the species and it is unlikely that they will ever naturally repopulate.

Question 7

An increase in the number of polar bears seen visiting human settlements indicates that

Accepted Answer

The increase in polar bears visiting human settlements could indicate that their natural food sources are being depleted, which could be due to limited hunting. This leads the bears to seek food in human settlements more frequently. It does not necessarily mean that polar bear populations are increasing, nor does it suggest that human food is more appealing to polar bears than wild seals. Therefore, option B is the best choice.

Question 8

While the hide of a male lion in Kenya will bring in $1,000, if the same male lion lives to age seven, he would bring in approximately ____ ecotourist dollars.

Accepted Answer

A male lion living to age seven can generate approximately $515,000 in ecotourist dollars, significantly more than the value of its hide.

Question 9

A bioprospector is most likely someone who

Accepted Answer

A bioprospector is someone who searches for natural resources in living organisms such as plants and animals. Option B best describes this activity as it involves testing plants and animals in various ecosystems for potentially useful chemicals, such as those that could be used in medicinal drugs. The other options (A, C, D, and E) do not accurately describe the role of a bioprospector.

Question 10

National parks can be viewed as habitat islands surrounded by

Accepted Answer

National parks are often isolated areas of natural habitat surrounded by human activities such as mining, logging, agriculture, and industrial activity, which can impact the ecosystems within the parks.

Question 11

In the year 1900, there were over 315,000 wild orangutans. What percentage of this number remains in the wild, and where are the majority of them located?

Accepted Answer

As of recent estimates, only about 10% of the original population of wild orangutans remains, and the majority are located in Indonesia.

Question 12

The greatest threat to most species is

Accepted Answer

Loss of habitat is the greatest threat to most species as it can cause displacement, food scarcity, and eventually extinction. Human activities such as deforestation, urbanization, and industrialization are major causes of habitat loss for many species. Water pollution, parasites, and sport hunting are localized threats to certain species, while climate change is a global threat that exacerbates habitat loss and affects multiple species.

Question 13

The greatest eliminator of species is habitat destruction of

Accepted Answer

Tropical forests are the most biologically diverse ecosystems on Earth and their destruction has resulted in the highest rates of species extinction. Deforestation and habitat destruction caused by human activities such as agriculture, mining, and logging are the primary causes of loss of tropical forests. The loss of these habitats has a cascading effect on the biodiversity of the entire planet.

Question 14

Causes of extinction and reduction in wild species' populations include all of the following except

Accepted Answer

Habitat loss, human population growth, pollution, and invasive species are all known causes of extinction and reduction in wild species' populations. Sustainable development, on the other hand, aims to balance economic growth with environmental protection and social responsibility to prevent these negative outcomes. Thus, sustainable development would not directly contribute to the decline in wild species' populations.

Question 15

The current rate of extinction is between _____ and _____ times the rate that existed before humans arrived on Earth.

Accepted Answer

The current rate of extinction is estimated to be between 100 and 1,000 times higher than the natural background rate due to human activities.

Question 16

Which one of the following statements about polar bears is not true?

Accepted Answer

There is no evidence to suggest that polar bears are a significant threat to wolf populations in Alaska. In fact, polar bears and wolves have been observed to interact and even scavenge from each other's kills.

Question 17

Some biodiversity experts advise us to focus our efforts on

Accepted Answer

Biodiversity hotspots are areas with high levels of species richness and endemism but are also threatened by habitat destruction and climate change. Focusing on slowing high rates of extinction in these areas can have the greatest impact on overall biodiversity preservation.

Option B, C, D, and E are not the best choices as slowing extinction in temperature deciduous forests, saving single important species, saving only the polar bear, or saving fish population alone may not necessarily preserve the overall biodiversity.

Question 18

Philip Levin, Donald Levin and other biologist have cautioned us that speciation rates can increase for opportunistic species such as

Accepted Answer

Opportunistic species like weeds, rodents, and cockroaches have high reproductive rates and adaptability, allowing them to thrive and speciate rapidly in changing environments.

Question 19

Geologic records indicate that the earth has experienced perhaps ________mass extinction(s) where up to ______________percent of the species disappeared.

Accepted Answer

Geologic records indicate that there have been 5 mass extinctions in the history of the Earth, with the most severe being the Permian-Triassic extinction event which resulted in the loss of up to 95% of species. Therefore, option B, which states that there have been 5 mass extinctions where up to 95% of species disappeared, is the correct answer.

Question 20

People who believe that wild species have an inherent right to exist generally believe in

Accepted Answer

People who believe in the inherent right of wild species to exist generally follow a stewardship view, which emphasizes the moral responsibility of humans to protect and preserve the natural environment for its own sake, rather than for any economic or utilitarian reasons. These individuals believe that all living organisms have an inherent value and a right to exist, and that it is the responsibility of humans to maintain and protect biodiversity.

Quiz 8: Sustaining Biodiversity: the Species Approach