LS7B Week 10

Most climate models predict that, during the 21st century, mean global temperature will increase by:

2-5°C.

How many "cells" of circulating air are found around the Earth?

6

What is the approximate size of the human population today?

7 billion people

In general, what is the relationship between a country's ecological footprint and its overall standard of living?

As the standard of living increases, so does the ecological footprint.

Autotrophs remove _____ from the air and fix this into tissues providing _____ for secondary consumers.

CO2; energy

Nutrients from croplands are carried by the Mississippi River into the Gulf of Mexico. If nutrients are good for growth, why are scientists concerned about this nutrient influx?

Higher productivity may result in increased respiration on sinking algal material, depleting oxygen within gulf waters.

Why are microorganisms like fungi, bacteria, and archaeons so important to the carbon cycle? -These microorganisms generate the oxygen necessary for aerobic organisms. -These microorganisms form their own portion of the carbon cycle in case other areas of the carbon cycle fail. -Many of these microorganisms generate carbon dioxide, making it available for primary producers. -These microorganisms bridge the carbon cycle between terrestrial and marine environments.

Many of these microorganisms generate carbon dioxide, making it available for primary producers.

So-called "dead zones" in coastal oceans are associated with nutrient runoff and oxygen-depleted bottom waters. What causes the oxygen depletion? -Nutrient runoff causes population growth of cyanobacteria and algae which, in turn, support the growth of fish populations. Fish consume oxygen via aerobic respiration. -Nutrient runoff causes algae and cyanobacteria populations to grow. When they die, they are consumed by heterotrophic bacteria that consume oxygen via aerobic respiration. -Nutrient runoff causes population growth of algae, which consume oxygen via aerobic respiration. -Nutrient runoff causes population growth of cyanobacteria and algae, which consume oxygen via aerobic respiration. -Nutrient runoff causes the waters to warm, which causes them to lose oxygen.

Nutrient runoff causes algae and cyanobacteria populations to grow. When they die, they are consumed by heterotrophic bacteria that consume oxygen via aerobic respiration.

Which of the following statements explains how an oxygen-rich atmosphere was possible? -The number of plants has always outnumbered the animals. -All of these choices are correct. -Rates of carbon fixation and respiration have always been equal. -Rates of oxygen consumption were lower than rates of photosynthesis. -Photosynthetic organisms have existed on earth longer than heterotrophs.

Rates of oxygen consumption were lower than rates of photosynthesis.

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 most likely accounts for this increase in methane levels?

The release of methane from thawed permafrost.

Biologists who study biodiversity describe new species and monitor species of which we are aware. Why is the study of biodiversity important in the Anthropocene? -The study of biodiversity is important because it provides information about the number of species that go extinct every 1000 years. -The study of biodiversity is important because it helps quantify the effects of human actions on changes in the traits of many populations (size, density, distribution). -The study of biodiversity is important because if we don't count all the species on the planet, then we won't be able to identify more potential sources of -The study of biodiversity is important because many politicians are biologists and they can influence government policy.

The study of biodiversity is important because it helps quantify the effects of human actions on changes in the traits of many populations (size, density, distribution).

Rainforests have high tree species richness, but low density. In deciduous forests the pattern is the opposite. Which of the following is NOT a plausible explanation for this pattern? -Because there are fewer organisms that can adapt to higher latitudes, there are fewer "pest" species that could easily move between trees in close proximity. -There are fewer species in temperate regions because the number of trees per hectare is lower than in tropical rainforests. -Many deciduous tree species are pollinated by wind, so individuals must be more closely spaced to one another for fertilization to occur. -Organisms that are adapted to the variability in higher latitudes are able to achieve higher population sizes.

There are fewer species in temperate regions because the number of trees per hectare is lower than in tropical rainforests.

Which of the following statements reflects an evolutionary change that is in line with the Red Queen hypothesis? -a species of beetle that begins to hybridize with another species of beetle in its habitat -a species of beetle that goes extinct when farmers start spraying insecticide -a species of beetle that switches to production of offspring solely through parthenogenesis -a species of beetle that has two new mutations that confer resistance to an insecticide

a species of beetle that has two new mutations that confer resistance to an insecticide

Which of the following factors likely contributed to the accumulation of O2 within Earth's atmosphere? -the evolution of cyanobacteria -the fact that there is a slight "de-coupling" between photosynthesis and respiration -the fact that oxygen is also cycled during the carbon cycle -the fact that photosynthesis releases O2 as a product -All of these choices are correct.

all are correct

Which of the following statements about coral bleaching is TRUE? -Increased seawater temperature is one cause of coral bleaching. -All of these choices are correct. -Bleached corals die more rapidly than unbleached corals. -Coral bleaching results from the loss of algal symbionts from the coral tissue. -Corals appear white after bleaching because their white calcium carbonate skeletons are visible through their translucent tissue.

all are correct

An individual's ecological footprint is equivalent to the:

amount of land required to provide all the resources used by that individual.

If a scientist wanted to determine if a forest environment had been polluted, which of the following groups of organisms typically would be the BEST indicator for the presence of pollutants?

amphibians

On land, _____, which are broad, ecologically uniform areas, are recognized by their characteristic vegetation that reflects adaptation of form and physiology to climate.

biomes

In addition to burning fossil fuels, humans return CO2 to the atmosphere faster than it can be removed by: -clearing forests for agriculture. -expanding rice production. -polluting the oceans. -generating nutrient pollution.

clearing forests for agriculture

Sustainable development plans are designed to allow: -conservation of species used by humans so that decreases in population size can be easily monitored and reversed. -conservation of species that are only found in regions of high human population because those are most likely to decline in population through human use. -conservation of species used by humans without causing the decline or extinction of that species. -conservation of species that are only found in the oceans because population sizes are easier to maintain in marine species.

conservation of species used by humans without causing the decline or extinction of that species.

The high specific heat of water means that land masses near the equator are: -cooler than predicted because of all the heat carried by ocean waters from low to high latitudes. -the same temperature regardless of the presence of water because it is only the amount of solar radiation on the land mass that affects temperature. -warmer than predicted because of all the heat in the water being released into the air.

cooler than predicted because of all the heat carried by ocean waters from low to high latitudes.

Moderate temperatures and precipitation, as well as nutrient-rich soil due to annual leaf fall, characterize this biome.

deciduous forest

In terrestrial ecosystems, nitrogen is returned to the atmosphere by:

denitrifying bacteria

Which of these biomes receives the least amount of rainfall, and therefore has low primary production, nutrient-poor soil, and plant species that are adapted for water-storage?

desert

In deeper waters, nutrients primarily come from:

detritus from more productive shallower waters.

Increased phosphate levels in the Everglades has led to: -increased plant growth and diversity. -displacement of native plants by phosphate-loving introduced plants. -expansion of native plants into adjacent ecosystems. -eutrophication followed by declines in fish and alligator populations. -declining populations of low-phosphate adapted cattails.

displacement of native plants by phosphate-loving introduced plants.

In marine ecosystems phosphorus is added to the ecosystem primarily from: -fixation of atmospheric phosphorus. -erosion of rocks on land. -dead organisms that fall to the bottom of the ocean. -glacial ice melt.

erosion of rocks on land

Nitrogen runoff leads to large increases in the populations of algae and cyanobacteria in lakes and oceans in a process known as:

eutrophication

If all of the tertiary consumers were removed from an environment, the associated food web (and thus the carbon cycle) would collapse. (T/F)

false

Most of Earth's primary production comes from tropical rainforests. (T/F)

false

In which of the following regions would you expect to find river biomes with HIGH levels of oxygen in the water? -fast-moving, muddy rivers in the Amazon -slow-moving, muddy rivers in the Amazon -fast-moving, clear-water rivers in the Rockies -slow-moving, clear-water rivers in the Rockies

fast-moving, clear-water rivers in the Rockies

Genetic variation within species is important to conservation because: -genetic variation provides material for natural selection to "act upon" in changing environments. -low levels of genetic variation may make hybrid species more likely, so neither species will go extinct. -species with low genetic variation go extinct. -high levels of genetic variation will result in more populations' speciating, so biodiversity will be maintained.

genetic variation provides material for natural selection to "act upon" in changing environments.

A dead zone has been documented off the coast of Oregon. Which of the following could contribute to the formation of the dead zone? -high carbon dioxide levels in the area -high phosphate levels in the area -high nitrogen levels in the area -high oxygen levels in the area

high nitrogen levels in the area

Remember that, as a rule, temperatures decrease with an increase in altitude. 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, you would predict that species ranges would show a shift toward:

higher elevations

If phosphorus concentrations were to suddenly increase in a marine ecosystem, which of the following would likely occur? -increased primary productivity -decreased primary productivity -no change in the rate of primary productivity

increased primary productivity

As a young field biologist, you are walking through a patch of grassland where you notice that there is a very common, well-established species of grass. Further research shows that this grass is native to an area in another part of the world. This species of grass would be classified as a(n) _____ species.

invasive

Which of the following statements is TRUE regarding the process of eutrophication? -All of these choices are correct. -It can result in "dead zones" devoid of aquatic animal life. -It increases the species diversity and health of bodies of water. -It is the result of the natural accumulation of nitrogen in bodies of water. -It increases the oxygen content of water by promoting bacterial growth.

it can result in dead zones

Warm air is _____ dense than cold air, and warm air holds _____ moisture than cold air.

less; more

Given models of population growth, which model would be the BEST to use for determining estimated sustainable yield?

logistic

Ultimately, the nitrogen cycle is dependent on: -microorganisms that convert atmospheric N2 into usable forms. -addition of fertilizers to the soil. -nitrogenous waste production in different environments. -respiration rates of heterotrophs.

microorganisms that convert atmospheric N2 into usable forms.

In either freshwater or marine biomes, which regions would you expect to have the HIGHEST productivity? -in the middle depths of the biome -at the deepest depth of the biome -near the surface where sunlight penetrates -just below the deepest level where sunlight penetrates

near the surface where sunlight penetrates

Some biologists have suggested that overexploitation in the harvesting of some sharks (i.e. top predators) has caused drastic changes in marine communities. Which of the following would you expect after removal of a top predator from a community?

population growth of prey species

Which of the following organisms can incorporate atmospheric carbon directly into C6H12O6, thereby playing a major role in a food web? -consumers -primary producers -carnivores -decomposers -grazers

primary producers

Eutrophication describes the:

process in which added nutrient levels lead to the growth of algae and cyanobacteria populations, eventually causing oxygen availability to decline.

What is one "low-tech" method currently available to actively remove CO2 from the air?

reforestation of previously cleared landscapes

Decomposers are vital components of a food web because they: -incorporate the carbon contained in atmospheric CO2 into C6H12O6. -return carbon (as CO2) to the atmosphere. -serve as primary producers. -immediately provide tertiary consumers with usable forms of carbon.

return carbon (as CO2) to the atmosphere.

If Earth had no oceans, would temperatures at the equator be hotter or colder than they are now?

temperatures would be hotter

Biological reserves are an important tool in maintaining biodiversity because a reserve: -that is designed to protect the species there will always be maintained as a reserve. -will not change over time so all the species will be conserved as long as the reserve exists. -will generate income when people visit to see the biodiversity protected in the reserve. -that is designed for a single species will also protect other species in the reserve.

that is designed for a single species will also protect other species in the reserve.

The hypothesis that species diversity is greater at lower latitudes than higher latitudes because low-latitude habitats are older would be supported if speciation rates were: -higher at low latitude than at high latitude. -more variable at low latitude than at high latitude. -more variable at high latitude than at low latitude. higher at high latitude than at low latitude. -the same at high and low latitudes.

the same at high and low latitudes.

As you hike from the base of a mountain to the top of a mountain, you would expect see decreasing levels of biodiversity. (T/F)

true

If all other aspects of their lifestyles were equivalent, a vegetarian would have a smaller ecological footprint than someone who consumes a large amount of meat. (T/F)

true

Increased overfishing on predators of crown-of-thorns starfish is likely to result in continued increase in crown-of-thorns starfish population sizes. (T/F)

true

Some forms of M. tuberculosis are very difficult—or even impossible—to treat with antibiotics. (T/F)

true

The evolution of biodiversity on the planet can be linked to patterns in the carbon cycle over time. (T/F)

true

This biome is the coldest, with the lowest biodiversity and a permanent layer of ice beneath the soil. -savanna -alpine -tundra -temperate coniferous forest -taiga

tundra