Question 1

Explain why a species with a very limited niche is particularly susceptible to human influences.

Accepted Answer

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Question 2

If the number of fruits on 10 strawberry plants is sampled and E[χ] is found to be 6 and E[χ²] is 38, what is the sample variance?

Accepted Answer

The sample variance is calculated using the formula Var(χ) = E[χ²] - (E[χ])². Substituting the given values, Var(χ) = 38 - 6² = 38 - 36 = 2. Therefore, the sample variance is 2.

Question 3

Describe one specific successful solution to an environmental problem caused by human activity.

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Question 4

Explain the potential difficulties of using a natural experiment to test a hypothesis.

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Question 5

Explain why the sample variance is larger than the variance of the mean, especially for small samples.

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Question 6

Ecologists using global carbon-balance models were overestimating the rate of increase of atmospheric carbon dioxide. This discovery led these ecologists to

Accepted Answer

The discovery that ecologists were overestimating the rate of increase of atmospheric carbon dioxide led them to search for evidence of other carbon dioxide sinks in the global cycle of carbon. This is because despite the overestimation, it is still understood that the increase in atmospheric carbon dioxide is a serious environmental problem, and finding other carbon dioxide sinks would be crucial to better understanding and addressing the issue.

Question 7

Use the example of the California sea otter to explain why ecologists must study multiple hierarchical levels to understand most environmental problems.

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Question 8

Which would be the most informative about the reliability of data gathered in an experiment?

Accepted Answer

A low variance indicates that the data points are clustered closely together, suggesting that the experiment was controlled and produced consistent results. Conversely, a high variance indicates that the data points are more spread out, implying that there were confounding variables or inconsistencies in the experiment, compromising the reliability of the data. Mean alone does not provide information about data variability or reliability.

Question 9

Which of the following has NOT caused increased habitat destruction?

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Question 10

Scientists ask questions about how the natural world works. These can usually be classified as how questions or why questions. A scientist observes that an owl species can fly silently. Give an example of a how and a why question that the scientist might study and what the differences would be.

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Question 11

What is the mean of these data: 22, 19, 34, 24, 27, 20?

Accepted Answer

Mean is the sum of all values divided by the number of values in a dataset. In this case, the mean can be calculated as (22+19+34+24+27+20) / 6 = 144 / 6 = 24. Therefore, the mean of the given data is 24.

Question 12

Which is the best action if an experiment does not support a hypothesis?

Accepted Answer

If an experiment does not support a hypothesis, the best action is to revise the hypothesis. This allows for the incorporation of new information and a deeper understanding of the research question. Creating a mathematical model could be helpful in some cases, but it is not always necessary. Testing the hypothesis again may yield the same results and would be a waste of resources. Publishing the results is important, but it does not address the issue of the unsupported hypothesis.

Question 13

The formulation of hypotheses is a critical step in the scientific process. In the simplest terms, what is an hypothesis?

Accepted Answer

An hypothesis is an explanation or proposed explanation for a phenomenon or set of observations.

Question 14

A scientist hypothesizes that the larvae of a particular species of swallowtail butterfly uses olfaction (the sense of smell) to locate their preferred host plants in the carrot family. To test the hypothesis, the scientist uses extracts from various plants-including some from the carrot family-to moisten small pieces of paper arranged randomly under a wire screen. Swallowtail larvae are released on the wire screen but cannot come into direct physical contact with the pieces of paper. What is the advantage of this experiment compared with simply presenting the larvae with a choice among various plants?

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Question 15

Explain the role of ecology in efforts to reduce the damage humans do to the environment.

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Question 16

Most scientific investigations begin with a set of facts about nature. These facts are obtained by

Accepted Answer

Scientific investigations typically begin with observations and descriptions of natural phenomena. This provides a foundation of factual information from which hypotheses can be developed and tested through experimentation or the development of mathematical models.

Question 17

Because it is difficult to experiment on large ecological systems, researchers often replicate the essential features of a system in smaller, simplified laboratory or field settings known as

Accepted Answer

Microcosms are small-scale replicas of larger, more complex ecological systems. They allow researchers to manipulate and observe key variables in a controlled environment, providing insight into how the larger system may operate.

Question 18

Fishermen living along the North Pacific Rim felt threatened by increased populations of sea otters because sea otters consume commercially valuable abalone, sea urchins, and spiny lobster. What beneficial aspect of sea otter ecology did these fishermen ignore?

Accepted Answer

The fishermen ignored the beneficial aspect of sea otter ecology where they catch and eat sea urchins, thereby protecting kelps, which shelter populations of larval fish. This, in turn, contributes to the overall health of the ecosystem and the balance of marine life populations.

Question 19

If you wanted to understand the impact of an introduced species on existing species in an area, what ecological level should you examine?

Accepted Answer

In order to understand the impact of an introduced species on existing species in an area, we need to examine the interactions between the different species that make up a community. This would include analyzing how the new species interacts with the existing species in terms of competition for resources, predation, and any other ecological factors that may come into play. Therefore, the appropriate ecological level to examine would be the community level.

Question 20

An experimental control is

Accepted Answer

A control group is an experimental group that does not receive the manipulation or factor of interest. It is used to isolate the effects of the manipulation and observe the changes in the dependent variable that are due to the manipulation. Therefore, a manipulation without the factor of interest is the best description of an experimental control. The other options do not accurately describe an experimental control.

Quiz 1: Introduction: Ecology, Evolution, and the Scientific Method