Question 1

Erwin and Scott used an insecticidal spray to remove insects from the top section of an L. seemannii tree and collect them from the forest floor. Using the data collected, Erwin projected that this entire tree, from top to bottom, is host to about 600 unique arthropod species, which were not found on any other tree species. While the researchers also identified 900 beetle species from the top section, the vast majority of them were known to be found on many other tree species. If there are approximately 50,000 species of tropical trees, and assuming that every tree hosts a similar number of unique species, which of the following would be the best quantitative method to roughly estimate the total number of arthropod species, globally?
A) Estimate the species density and then multiply by 50,000.
B) Multiply 600 by 50,000.
C) Multiply 50,000 by 900.
D) Add 900 to 600, and then multiply by 50,000.

Accepted Answer

Since the question asks for an estimate of the total number of unique arthropod species globally, based on the assumption that every tree hosts a similar number of unique species (600), multiplying the number of unique species (600) by the total number of tropical tree species (50,000) provides the best estimate.

Question 2

A parasitic fungus, Geomyces destructans, has decimated millions of bats in the United States since it was first observed in upstate New York in 2006. The disease has been named white-nose syndrome because of the white fungal hyphae that cover the bat upon infection. It is believed that this fungus was introduced from Europe by tourists entering into caves with hibernating bat populations. Which prediction most likely reflects changes that will occur in natural communities as a result of massive bat mortality?
A) increased animal populations as a result of niche availability
B) increased rodent populations as a result of an increase in flying insect populations
C) increased flying insect populations
D) decreased bird populations as the spread of the fungus infects other closely related species

Accepted Answer

With the decline in bat populations due to white-nose syndrome, there would likely be an increase in flying insect populations, as bats are major predators of these insects.

Question 3

Suppose you attend a town meeting at which some experts tell the audience that they have performed a cost-benefit analysis of a proposed transit system that would probably reduce overall air pollution and fossil fuel consumption. The analysis, however, reveals that ticket prices will not cover the cost of operating the new system. As a biologist, you know that if ecosystem services had been included in the analysis, the experts might have arrived at a different conclusion. Which of the following best explains why ecosystem services are rarely included in economic analyses?
A) Federal laws of the United States exclude their inclusion in any cost benefit analysis.
B) They have a low value and are usually not cost effective.
C) Ecosystem services only take into account abiotic factors that affect local environments.
D) Their cost is difficult to estimate, and people take them for granted.

Accepted Answer

Ecosystem services are often overlooked in economic analyses because their value is hard to quantify, and they are generally taken for granted. This makes it challenging to incorporate them into cost-benefit analyses, even though they can significantly impact the overall evaluation of projects like transit systems.

Question 4

Which of the following terms includes all of the others?
A) species diversity
B) biodiversity
C) genetic diversity
D) ecosystem diversity

Accepted Answer

Biodiversity encompasses all forms of life and their variations, including species diversity, genetic diversity, and ecosystem diversity.

Question 5

Which of the following observations provides the best evidence of a biodiversity crisis?
A) the incursion of a non-native species
B) increasing pollution levels
C) high rate of extinction
D) climate change

Accepted Answer

The high rate of extinction directly indicates a loss of biodiversity, as it means species are disappearing at an alarming rate. This is a direct measure of biodiversity loss, making it the best evidence of a biodiversity crisis among the options provided.

Question 6

If all individuals in the last remaining population of a particular frog species were all highly related, which type of diversity would be of greatest concern when planning to prevent the species from going extinct?
A) global diversity
B) local diversity
C) ecosystem diversity
D) genetic diversity

Accepted Answer

Genetic diversity is crucial for the survival of a species, especially in small, highly related populations, as it affects the population's ability to adapt to changing environments and resist diseases.

Question 7

Philippe Bouchet and colleagues conducted a massive survey of marine molluscs on the west coast of New Caledonia. For 20% of the total species that were located and identified, only a single specimen was found. Which of the following claims about the diversity of molluscs in this area is best supported by the evidence?
A) The west coast of New Caledonia is not an appropriate habitat for molluscs.
B) Many of the species from this 20% are probably rare.
C) They were not sampling uniformly throughout the area.
D) Many of the species from this 20% are most likely just dispersing through the area.

Accepted Answer

Finding only a single specimen of 20% of the species suggests that these species are rare in the area, rather than indicating issues with habitat suitability, sampling methods, or that these species are merely passing through.

Question 8

Which of the following threats to biodiversity impacts a specific species at one time, but also has the capacity to impact many other species due food-web interactions?
A) introduced species
B) habitat destruction
C) increased levels of atmospheric carbon dioxide, a cause of global warming
D) overharvesting

Accepted Answer

The answer of Which of the following threats to biodiversity...

Question 9

Which of the following statements regarding extinction is the most accurate?
A) A large percentage of species are immune from extinction; however, rates of extinction may increase with continued human impacts.
B) Extinctions occur only periodically, separated by long time spans with no extinctions.
C) Extinction is occurring at a similar rate now as compared to historical fossil evidence.
D) The small-population approach is inferior to the declining-population approach if the goal is to conserve the maximum number of species in a given region.

Accepted Answer

The small-population approach focuses on species that are already at great risk of extinction due to their small population sizes, while the declining-population approach aims to identify and mitigate the factors causing populations to decline before they reach critically low levels. The declining-population approach is generally considered more effective for conserving the maximum number of species because it addresses problems earlier in the process of population decline, potentially preventing species from becoming critically endangered in the first place.

Question 10

Researchers have been studying a rare population of 87 voles in an isolated area. Ten voles from a larger population were introduced into this isolated population. Besides having ten more individuals, which of the following is another benefit of the addition?
A) Increasing the consumption of producers.
B) Strengthening competition between voles and thereby increasing the survival of the fittest.
C) Increasing the beneficial effects of genetic drift.
D) Increasing genetic diversity.

Accepted Answer

Introducing new individuals into a small, isolated population can increase genetic diversity, which is beneficial for the health and adaptability of the population. Genetic diversity helps in reducing the risks associated with inbreeding and can enhance the population's ability to adapt to environmental changes.

Question 11

Overharvesting encourages extinction and is most likely to affect?
A) animals that occupy a broad ecological niche
B) large animals with low intrinsic reproductive rates
C) most organisms that live in the oceans' coral reefs
D) edge-adapted species

Accepted Answer

Large animals with low intrinsic reproductive rates are most likely to be affected by overharvesting because their populations recover more slowly from reductions, making them more vulnerable to extinction.

Question 12

Which of the following is necessary in order to better comprehend the magnitude of current extinctions?
A) differentiate between plant extinction and animal extinction numbers
B) focus on identifying more species of mammals and birds
C) identify more of the yet unknown species of organisms on Earth
D) use the average extinction rates of vertebrates as a baseline

Accepted Answer

Identifying more of the yet unknown species of organisms on Earth is crucial for comprehending the magnitude of current extinctions because it provides a more accurate picture of biodiversity loss. Without knowing how many species exist, it's difficult to understand the full extent of species disappearing.

Question 13

Which of the following criteria must be met for a species to qualify as invasive?
A) endemic to the area, spreads rapidly, and displaces foreign species
B) introduced to a new area, spreads rapidly, and displaces native species
C) introduced to a new area, spreads rapidly, and displaces other invasive species
D) endemic to the area, spreads slowly, and displaces native species

Accepted Answer

An invasive species is one that is not native to a specific location (introduced to a new area) and has a tendency to spread to a degree believed to cause damage to the environment, human economy, or human health. The key aspects of an invasive species include its introduction to a new area, rapid spread, and the displacement of native species.

Question 14

Which of the following best describes how introduced species can have deleterious effects on the biological communities they invade?
A) competing with native species for resources and displacing them
B) spreading rapidly in their new region
C) reducing erosion
D) increasing the biodiversity in their new region

Accepted Answer

Introduced species can outcompete native species for resources such as food, space, and light, leading to the displacement or extinction of native species, which can disrupt the ecosystem balance.

Question 15

Which of the following best describes the biological significance of genetic diversity between populations?
A) Genes for traits conferring an advantage to local conditions are unlikely.
B) The population that is most fit would survive by competitive exclusion.
C) Genetic diversity reduces the probability of extinction.
D) Diseases and parasites are not spread between separated populations.

Accepted Answer

Genetic diversity within and between populations increases the resilience of those populations to environmental changes, diseases, and other threats, thereby reducing the probability of extinction. This diversity ensures that some individuals may possess traits that allow them to survive changing conditions or challenges, thus preserving the survival and adaptability of the population as a whole.

Question 16

Tropical forests are being converted to farm or pasture land at an alarming rate. The impact of the deforestation on the biodiversity of the ecosystem is a major focus of research and conservation efforts. Which of the following is a direct benefit to humans that best explains why these forests need to be preserved?
A) Biodiversity in the tropics increases the potential to store more carbon from the atmosphere.
B) Natural and undisturbed areas are important wildlife habitats.
C) The diversity could contain novel medications for consumers.
D) The plant diversity provides unique areas for ecotourism.

Accepted Answer

The diversity in tropical forests could contain novel medications for consumers, providing a direct benefit to humans through potential medical discoveries.

Question 17

Which of the following can be caused by nitrogen and sulfur oxide air pollutants, which are released during the burning of fossil fuels?
A) the death of fish in lakes
B) precipitation with a pH as high as 8.0
C) eutrophication of lakes
D) global temperature decrease

Accepted Answer

Nitrogen and sulfur oxides can lead to acid rain, which lowers the pH of water bodies, harming aquatic life and potentially causing the death of fish in lakes.

Question 18

Of the following ecosystem types, which have been impacted the most by humans?
A) wetland and riparian
B) desert and high alpine
C) taiga and second-growth forests
D) tundra and arctic

Accepted Answer

Wetland and riparian ecosystems have been significantly impacted by human activities such as agriculture, urban development, and pollution, leading to habitat destruction and degradation.

Question 19

Loss of biodiversity matters not only with regard to mammals or other vertebrates, but also to microbes. Which of the following best explains the importance of discovering and protecting microbes from extinction?
A) Microbes play a role in digestion.
B) Microbes may produce unique proteins useful in genetic research.
C) Microbes are much greater in species number than any other taxa on Earth.
D) Microbes may be the most sensitive to the next large extinction event.

Accepted Answer

Microbes may produce unique proteins useful in genetic research, which highlights their potential importance in scientific and medical advancements.

Question 20

Which of the following is an ecosystem service that includes processes that increase the quality of the abiotic environment?
A) Keystone predators have a marked effect on species diversity.
B) Green plants and phytoplankton produce the oxygen we breathe.
C) Bees, flies, and wasps pollinate many plants.
D) The presence of dams improves flood control.

Accepted Answer

Green plants and phytoplankton contribute to the production of oxygen through photosynthesis, which is a process that directly increases the quality of the abiotic (non-living) environment by enriching the atmosphere with oxygen necessary for the survival of many organisms.

Quiz 56: Conservation and Global Ecology

Which of the following terms includes all of the others?

Which of the following observations provides the best evidence of a biodiversity crisis?

If all individuals in the last remaining population of a particular frog species were all highly related, which type of diversity would be of greatest concern when planning to prevent the species from going extinct?

Which of the following threats to biodiversity impacts a specific species at one time, but also has the capacity to impact many other species due food-web interactions?

Which of the following statements regarding extinction is the most accurate?

Researchers have been studying a rare population of 87 voles in an isolated area. Ten voles from a larger population were introduced into this isolated population. Besides having ten more individuals, which of the following is another benefit of the addition?

Overharvesting encourages extinction and is most likely to affect?

Which of the following is necessary in order to better comprehend the magnitude of current extinctions?

Which of the following criteria must be met for a species to qualify as invasive?

Which of the following best describes how introduced species can have deleterious effects on the biological communities they invade?

Which of the following best describes the biological significance of genetic diversity between populations?

Which of the following can be caused by nitrogen and sulfur oxide air pollutants, which are released during the burning of fossil fuels?

Of the following ecosystem types, which have been impacted the most by humans?

Loss of biodiversity matters not only with regard to mammals or other vertebrates, but also to microbes. Which of the following best explains the importance of discovering and protecting microbes from extinction?

Which of the following is an ecosystem service that includes processes that increase the quality of the abiotic environment?