Question 1

If you were studying the effects of climate change on the geographic ranges of species living in the mountains and your climate records showed that mean temperatures were increasing, which species would you be MOST concerned about from a conservation standpoint?

Accepted Answer

A habitat specialist living at the highest elevations would have limited options for moving or adapting to the changing climate. They are already living at the edge of their tolerance range, and any increase in temperature would push them beyond what they can handle. This makes them most vulnerable to the consequences of climate change and in need of immediate conservation measures.

Question 2

A number of plant species have declined in abundance around Boston, Massachusetts, since Thoreau's time. These tend to be the plants that:

Accepted Answer

Plants that are least able to change their flowering time have declined in abundance since Thoreau's time, likely due to their inability to adapt to changing climate conditions.

Question 3

Using records taken by Henry David Thoreau in the 1840s, scientists have documented what pattern of change in flowering plants around Boston, Massachusetts?

Accepted Answer

Thoreau's records show that as temperatures have warmed over time, flowering has occurred earlier in many species of plants around Boston, Massachusetts.

Question 4

When the ecological footprints of every human on Earth are summed, this number corresponds exactly to the land area of Earth.

Accepted Answer

The statement is false. Currently, the ecological footprint of the average human exceeds their share of the Earth's bio-capacity, meaning that humans are using more resources and producing more waste than the Earth can sustain. As a result, the total ecological footprint of humanity exceeds the land area of Earth.

Question 5

Examine Figure 49.7 below and compare the projected change in temperature in central South America and central Africa at the equator (draw an imaginary line across the globe at its widest point and examine a spot in the middle of each continent along that line). Which of the following BEST describes the predicted changes?

Accepted Answer

Looking at the map, the color scale shows that the projected temperature change in central South America is around 7-8 degrees Celsius, while in central Africa it is around 3-4 degrees Celsius. Therefore, the best choice is A, where central South America will warm by an average of 7-8 degrees and central Africa will warm by around 3-4 degrees.

Question 6

Humans have a nearly ubiquitous influence on physical environments throughout the world. Looking back through geologic history, which type of organism can claim a comparable impact on physical environments?

Accepted Answer

Cyanobacteria, also known as blue-green algae, were responsible for the oxygenation of Earth's atmosphere through photosynthesis, dramatically altering the physical environment and paving the way for the evolution of more complex life forms.

Question 7

Carbon dioxide combines with water to form a weak _____; this has caused the pH of seawater to go _____.

Accepted Answer

When carbon dioxide combines with water it forms carbonic acid, hence it is an acid. This has caused the pH of seawater to go down or become more acidic.

Question 8

Geoengineering consists of a suite of widely debated proposals to mitigate global warming by actively managing Earth's radiation budget or greenhouse gas concentrations. Nobel laureate Paul Crutzen has proposed injecting sulfate aerosols into the stratosphere, which would reflect more incoming solar radiation away from the Earth, decreasing surface temperatures. Imagine we adopted this strategy for 100 years and then stopped. How would climate react at the end of the experiment?

Accepted Answer

Injecting sulfate aerosols into the stratosphere would temporarily cool the Earth by reflecting solar radiation away. However, once the intervention stopped, the aerosols would eventually settle out of the atmosphere, and the climate would quickly return to its warming trajectory, assuming greenhouse gas concentrations continued to increase as before.

Question 9

Giant sequoia trees (Sequoiadendron giganteum) are among the largest and longest-living organisms on Earth. These trees grow in weight by up to 1000 pounds of wood per year. As these trees are growing, they:

Accepted Answer

Giant sequoia trees, like all plants, incorporate CO2 into their biomass through photosynthesis, act as a net sink for CO2 by absorbing more than they emit, and generate CO2 through cellular respiration as part of their metabolic processes.

Question 10

About _____ of the CO₂ produced by humans during the past century has been absorbed by the ocean.

Accepted Answer

About one-third of the CO2 produced by humans during the past century has been absorbed by the ocean, significantly impacting its chemistry and contributing to ocean acidification.

Question 11

As oceans acidify, carbonate ions in the ocean:

Accepted Answer

As oceans acidify, the pH decreases, which causes the concentration of carbonate ions to decrease, making them less available to organisms that build calcium carbonate skeletons. This can lead to difficulties for these organisms to build and maintain their shells and skeletons, which can have cascading effects throughout marine ecosystems.

Question 12

Researchers have found that:

Accepted Answer

The answer of Researchers have found that:
...

Question 13

Oceans are about _____% more acidic than they were in the 1960s.

Accepted Answer

Oceans have become about 30% more acidic since the 1960s due to the absorption of excess carbon dioxide from the atmosphere, leading to ocean acidification.

Question 14

Which of the following statements about the growth of the human population is CORRECT?

Accepted Answer

None of the answer options are correct. The human population first reached 1 billion in the early 1800s, and it has been growing at an increasingly rapid rate since then. The doubling time of the human population has decreased from over 1,000 years at the beginning of the Common Era to approximately 61 years today. The human population is currently estimated to be around 7.9 billion.

Question 15

Examine Figure 49.5 below. According to this figure, mean temperature changes from 1940-1980 and 1999-2008 have been GREATEST:

Accepted Answer

The answer of Examine Figure 49.5 below. According to this...

Question 16

Which of the following statements about the concept of an ecological footprint is FALSE?

Accepted Answer

The statement that countries with the largest population sizes have the largest ecological footprints is not necessarily true. Ecological footprints can vary widely depending on factors like consumption behavior and resource availability. A country with a smaller population may have a higher ecological footprint if its citizens consume more resources per capita than a country with a larger population.

Question 17

There is a giant sequoia (Sequoiadendron giganteum) named Washington (after George Washington) that was believed to be the second largest tree in the world (253.7 ft. in height!) until it was struck by lightning in 2003. The lightning strike caused a fire at the top of the tree that reduced Washington's height to about 229 feet. Carbon released from the tree due to that fire could have:

Accepted Answer

Carbon released from the tree as CO2 could be taken up by nearby plants, including sequoias, through photosynthesis (A). It could also travel through the atmosphere and dissolve into the ocean (D).

Question 18

If a person wanted to change Earth's climate and came up with a way to add copious amounts of water vapor to the atmosphere, how would the climate be affected?

Accepted Answer

Water vapor is a potent greenhouse gas, so adding large amounts of it to the atmosphere would likely increase Earth's temperature. Additionally, altering the concentration of water vapor can change weather patterns, as it plays a crucial role in the formation of clouds and precipitation.

Question 19

A group of scientists in Alaska notices that not only have atmospheric CO₂ levels increased at their sampling site but so too have methane levels. What could account for this increase in methane levels?

Accepted Answer

The increase in both atmospheric CO₂ and methane levels suggests that the source of the methane is likely from a natural source rather than human activity. The melting of permafrost in Alaska can release large amounts of methane trapped beneath the surface, as it was formed by decomposing organic matter which can continue to decompose and release methane when exposed to warmer temperatures. Therefore, choice C, the release of methane from thawed permafrost, is the best option to account for the observed increase in methane levels.

Question 20

Which of the following statements about patterns of energy use among countries is NOT true?

Accepted Answer

This statement is not true. The size of a country does not necessarily correlate with the amount of energy its individuals use. Factors such as population density, industrialization, and standard of living play a larger role in determining energy use.

Quiz 49: The Anthropocene: Humans As a Planetary Force

If you were studying the effects of climate change on the geographic ranges of species living in the mountains and your climate records showed that mean temperatures were increasing, which species would you be MOST concerned about from a conservation standpoint?

A number of plant species have declined in abundance around Boston, Massachusetts, since Thoreau's time. These tend to be the plants that:

Using records taken by Henry David Thoreau in the 1840s, scientists have documented what pattern of change in flowering plants around Boston, Massachusetts?

When the ecological footprints of every human on Earth are summed, this number corresponds exactly to the land area of Earth.

Humans have a nearly ubiquitous influence on physical environments throughout the world. Looking back through geologic history, which type of organism can claim a comparable impact on physical environments?

Carbon dioxide combines with water to form a weak _; this has caused the pH of seawater to go _.

Giant sequoia trees (Sequoiadendron giganteum) are among the largest and longest-living organisms on Earth. These trees grow in weight by up to 1000 pounds of wood per year. As these trees are growing, they:

About _____ of the CO₂ produced by humans during the past century has been absorbed by the ocean.

As oceans acidify, carbonate ions in the ocean:

Researchers have found that:

Oceans are about _____% more acidic than they were in the 1960s.

Which of the following statements about the growth of the human population is CORRECT?

Examine Figure 49.5 below. According to this figure, mean temperature changes from 1940-1980 and 1999-2008 have been GREATEST:

Which of the following statements about the concept of an ecological footprint is FALSE?

If a person wanted to change Earth's climate and came up with a way to add copious amounts of water vapor to the atmosphere, how would the climate be affected?

A group of scientists in Alaska notices that not only have atmospheric CO₂ levels increased at their sampling site but so too have methane levels. What could account for this increase in methane levels?

Which of the following statements about patterns of energy use among countries is NOT true?

Quiz 49: The Anthropocene: Humans As a Planetary Force

If you were studying the effects of climate change on the geographic ranges of species living in the mountains and your climate records showed that mean temperatures were increasing, which species would you be MOST concerned about from a conservation standpoint?

A number of plant species have declined in abundance around Boston, Massachusetts, since Thoreau's time. These tend to be the plants that:

Using records taken by Henry David Thoreau in the 1840s, scientists have documented what pattern of change in flowering plants around Boston, Massachusetts?

When the ecological footprints of every human on Earth are summed, this number corresponds exactly to the land area of Earth.

Humans have a nearly ubiquitous influence on physical environments throughout the world. Looking back through geologic history, which type of organism can claim a comparable impact on physical environments?

Carbon dioxide combines with water to form a weak _____; this has caused the pH of seawater to go _____.

Giant sequoia trees (Sequoiadendron giganteum) are among the largest and longest-living organisms on Earth. These trees grow in weight by up to 1000 pounds of wood per year. As these trees are growing, they:

About _____ of the CO2 produced by humans during the past century has been absorbed by the ocean.

As oceans acidify, carbonate ions in the ocean:

Researchers have found that:

Oceans are about _____% more acidic than they were in the 1960s.

Which of the following statements about the growth of the human population is CORRECT?

Examine Figure 49.5 below. According to this figure, mean temperature changes from 1940-1980 and 1999-2008 have been GREATEST:

Which of the following statements about the concept of an ecological footprint is FALSE?

If a person wanted to change Earth's climate and came up with a way to add copious amounts of water vapor to the atmosphere, how would the climate be affected?

A group of scientists in Alaska notices that not only have atmospheric CO2 levels increased at their sampling site but so too have methane levels. What could account for this increase in methane levels?

Which of the following statements about patterns of energy use among countries is NOT true?

Carbon dioxide combines with water to form a weak _; this has caused the pH of seawater to go _.

About _____ of the CO₂ produced by humans during the past century has been absorbed by the ocean.

A group of scientists in Alaska notices that not only have atmospheric CO₂ levels increased at their sampling site but so too have methane levels. What could account for this increase in methane levels?