LS 7b post midterm 2

Oxygenic photosynthesis is carried out by which of the following types of bacteria?

bacteroidetes
E. coli
firmicutes
cyanobacteria
Streptococcus

cyanobacteria

What causes amoeboid feeding cells of cellular slime molds to aggregate into a large multicellular "slug" form?

low nutrient levels
proximity to other cells of the same species
increased sunlight
low moisture levellow

nutrient levels

The terms algae and protozoa have significant phylogenetic meaning. T/F

false

A researcher has discovered a new species of bacteria that is remarkably similar to E. coli in its morphology and rRNA sequences. How should the bacteria be classified?

as a gram-positive bacterium
as a proteobacterium
as an acidobacterium
as a firmicute
as a cyanobacterium

as a proteobacterium

You may know that scientists are able to synthesize new strands of DNA through a process known as PCR, which utilizes a DNA polymerase derived from bacteria. By repeatedly heating the reaction products to 70°C, researchers can create new DNA from a template DNA strand. What does this tell you about bacteria compared to archaeons?

that some bacteria can survive at high temperatures, although archaeons can survive in much hotter environments
that bacteria and archaeons can likely both survive at temperatures of 122°C
that archaeons prefer colder environments compared to bacteria
that some bacteria can survive at higher temperatures compared to archaeons

that some bacteria can survive at high temperatures, although archaeons can survive in much hotter environments

Methanogens are important in the carbon cycle because they help remove methane gas from the atmosphere. T/F

false

A student is carrying out a science experiment. She takes battery acid and introduces several different types of microorganisms into it. Which of the following organisms would MOST likely survive?

nanoarchaeote archaeons
thaumarchaeote archaeons
euryarchaeote archaeons
korarchaeote archaeons
both thaumarchaeote and nanoarchaeote archaeons

euryarchaeote archaeons

It is commonly thought that life originated in hot waters near marine hydrothermal vents. Which of the following provides evidence in support of this hypothesis?

Early diverging branches on the archaeon tree gave rise to Thaumarchaeota.
Thaumarchaeota have high abundance in deep ocean waters.
Euyarchaeota are extremely diverse.
Some bacterial lineages also have thermophilic members.

Some bacterial lineages also have thermophilic members.

Most eukaryotic cells contain mitochondria, but a few single-celled eukaryotic organisms found in oxygen-free environments do not. Which of the following observations led biologists to reject the hypothesis that these mitochondria-free eukaryotes evolved BEFORE the endosymbiotic event that established mitochondria in other eukaryotes?

All eukaryotes exhibit some sort of energy utilization.
Some eukaryotes don’t have mitochondria; they have chloroplasts instead.
All eukaryotes have remnant chloroplast genes.
The nuclear genome of these mitochondria-free eukaryotes contains relics of mitochondrial genes.

The nuclear genome of these mitochondria-free eukaryotes contains relics of mitochondrial genes

Chloroplasts are thought to have evolved from cyanobacteria. Which of the following observations support this hypothesis? (Select all that apply.)

They both have the capability of movement through flagella.
They both have cell walls.
They both have similar internal membranes that organize the light reactions of photosynthesis.
They both have small circular DNA genomes.

They both have similar internal membranes that organize the light reactions of photosynthesis. They both have small circular DNA genomes.

Organelles have their own genomes. When chloroplast DNA is sequenced and compared to genomes from members of the cyanobacteria, the sequence is nested within cyanobacteria. This is strong evidence for the hypothesis that:

photosynthesis evolved only once on the eukaryotic tree.
cyanobacteria are so diverse that any organelle genome would nest within the group.
cyanobacteria are descended from chloroplasts.
the chloroplast originated as a symbiotic cyanobacterium that became permanently incorporated into its host.

the chloroplast originated as a symbiotic cyanobacterium that became permanently incorporated into its host.

What is the main difference between the two hypotheses for the origin of the eukaryotic cell?

One hypothesizes that engulfment of a proteobacterium occurred after formation of the nuclear envelope rather than before.
Only one involves the conversion of a proteobacterium to a mitochondria.
One attributes the formation of the endoplasmic reticulum and nuclear envelope to infolding of the plasma membrane.
One hypothesizes that eukaryotic cells evolved from an archaeon rather than a bacterium.

One hypothesizes that engulfment of a proteobacterium occurred after formation of the nuclear envelope rather than before.

The last common ancestor of gymnosperms and angiosperms possessed which of the following characteristics? (Select all that apply.)

flowers
pollen
seeds
vascular tissues
double fertilization

pollen seeds vascular tissues

Which taxonomic group of land plants still in existence today was the dominant group of land plants when the angiosperms began their rapid increase in speciation and distribution?

bryophytes
gymnosperms
ferns and horsetails
lycophytes

gymnosperms

Recent climate simulations suggest that angiosperms may have been necessary for the formation of tropical rainforests as we know them today. T/F

true

Without the higher rates of transpiration exhibited by angiosperms, many tropical regions would:

have lower temperatures and lower rainfall.
have higher temperatures and higher rainfall.
have higher temperatures and lower rainfall.
have lower temperatures and higher rainfall.
be deserts.

have higher temperatures and lower rainfall.

Choanoflagellates are the closest protistan relatives of animals. T/F

true

Green algae are most closely related to:

diatoms.
brown algae.
red algae.
land plants.

land plants

What feature of animals enabled them to diversify in ways that plants, fungi, algae, and protozoans have not?

bilateral symmetry
organ systems
phylogenetic analysis
radial symmetry

organ systems

Early scientists used morphological characteristics to create a phylogeny of animals, but recently, DNA sequence data have helped in the revision of phylogenies of taxa within the larger groups (i.e., bilaterians, sponges, cnidarians). Why are morphological characteristics like "fate of the blastopore" or "body symmetry" relatively good at predicting larger-scale branching patterns on phylogenies?

These features reflect adaptations to life on land.
The development of these characteristics is controlled genetically, therefore similarities in DNA sequence would be expected in more closely related taxa.
All animals are descended from a common ancestor that had the traits described above.
Characteristics like those described are necessary for living, therefore all organisms must have those traits.

The development of these characteristics is controlled genetically, therefore similarities in DNA sequence would be expected in more closely related taxa.

Frogs, birds, rabbits, and lizards all have different forelimbs, which makes sense when you consider their different lifestyles. Interestingly, all of their forelimbs share the same set of bones the ulna, the radius, and the humerus. These same bones are also seen in fossils of the extinct animal Eusthenopteron, which demonstrates common ancestry among these four groups of animals. Hence, these forelimbs are an example of:

analogies.
homologies.
similes.
homilies.

homologies

What is the advantage of a fungal body being composed of numerous thin hyphae instead of one or two very thick hyphae?

More exposure to the sun allows for increased photosynthesis.
Less energy is required to produce the hyphae.
Better support is provided by numerous hyphae.
A greater surface area is available for absorption of nutrients.
All of these choices are correct.

A greater surface area is available for absorption of nutrients.

Which of the following is an example of a mutualistic association involving a fungus?

Fungal spores infect and then eventually kill an insect.
A fungus produces rings that allow it to capture and feed upon nematode worms.
A fungus invades the xylem of a tree and eventually kills it.
Fungal hyphae penetrate a plant root, then provide the plant with nutrients and receive organic molecules in return.
A fungus causes athlete’s foot in a human.

Fungal hyphae penetrate a plant root, then provide the plant with nutrients and receive organic molecules in return.

Imagine that fungal hyphae were as thick as a human hair. How might this increase in thickness affect the ecological role of fungi?

Their rates of decomposition of detritus would decrease because their ratio of surface area to volume would be decreased.
There would be no effect on the rates of decomposition of detritus because the fungi would still be heterotrophic.
Their rates of decomposition of detritus would increase because their ratio of surface area to volume would be increased.
There would be no effect on the rates of decomposition of detritus.

Their rates of decomposition of detritus would decrease because their ratio of surface area to volume would be decreased.

Lichens are able to obtain nutrients from their environment by:

digesting "pollutants" in highly polluted environments.
digesting small organisms that live on the surface of the lichen.
associating with a specific photosynthetic symbiont.
secreting organic acids that liberate nutrients from surrounding materials.

secreting organic acids that liberate nutrients from surrounding materials.

Which of the following statements about mycorrhizae is CORRECT?

The hyphae of ectomycorrhizal fungi penetrate plant root cells.
Endomycorrhizal fungi receive carbohydrates from plants, whereas ectomycorrhizal fungi do not.
Endomycorrhizal fungi provide plant roots with nutrients, whereas ectomycorrhizal fungi do not.
Endomycorrhizal fungi constitute a monophyletic group.
Endomycorrhizal fungi branch extensively in the soil surrounding plant roots, whereas ectomycorrhizal fungi do not.

Endomycorrhizal fungi constitute a monophyletic group.

What is the predominant hypothesis to explain why animals only appeared in the fossil record about 3 billion years after life originated?

There were animals 3 billion years ago, they just weren’t fossilized.
Animals are warm-blooded, and the ocean was too cold for animals to evolve 3 billion years ago.
Animals are heterotrophic and couldn’t evolve until there were enough photosynthetic organisms on Earth to support being eaten by animals.
Animals large enough to be recorded in the fossil record could not evolve until oxygen reached levels sufficient to support aerobic respiration.

Animals large enough to be recorded in the fossil record could not evolve until oxygen reached levels sufficient to support aerobic respiration.

The period of time during which an "explosion" of fossilized animals with bilateral symmetry are first found is the:

Jurassic.
Devonian.
Ediacaran.
Cambrian.

Cambrian.

The colonization of land by animals:

preceded the presence of plant species on land.
took place billions of years ago.
was made easier by high atmospheric levels of carbon dioxide.
may have taken place independently by a variety of species descended from aquatic ancestors.

may have taken place independently by a variety of species descended from aquatic ancestors.

Modern-day birds are MOST closely related to which of the following?

mammals
dinosaurs
lungfish
amphibians

dinosaurs

_____ allows populations to adapt to the abiotic and biotic conditions where they live.

Natural selection
Reproduction
Predation
Competition

natural selection

Large, even distances typically separate individual panda bears from each other. What type of population distribution do pandas exhibit?

sinusoidal distribution
logistic distribution
clustered distribution
random distribution
uniform distribution

uniform distribution

Which of the following results from a mark-recapture study done on mice would reflect a larger population size?

Both of these scenarios would result in the same population estimate.
When taking the second sample, 200 individuals are caught and 20 are marked from the first sample.
When taking the second sample, 200 individuals are caught and 80 are marked from the first sample.

When taking the second sample, 200 individuals are caught and 20 are marked from the first sample.

A _____ consists of all the individuals of a given species that live and reproduce in a particular place.

species
population
family
range

population

The size of a population of frogs is significantly below the population size that the environment can support. This could be the result of frog parasites and/or predators. T/F

true

An environment can only support a certain number of individuals from a given species at any one time. This number is referred to as the _____ of that environment.

population density
population size
carrying capacity
growth rate

carrying capacity

Most populations demonstrate _____ growth, in which the population size increases exponentially until it levels off near the K value of the habitat for that species.

logarithmic
intrinsic
exponential
extrinsic
logistic

logistic

What are the units of r?

individuals
change in individuals per unit time/individuals at starting time
individuals per unit time

change in individuals per unit time/individuals at starting time

A severe drought is an example of a density-_____ factor that can influence population size. The availability of nest sites is an example of a density-_____ factor.

dependent; independent
independent; dependent
independent; independent
dependent; dependent

independent; dependent

At its earliest stages, a logistic growth curve closely resembles an exponential growth curve. T/F

true

When a population is small relative to its carrying capacity, its growth will be:

both geometric and exponential.
exponential.
logistic.
geometric.
both geometric and logistic.

exponential.

The maximum number of individuals that a habitat can support:

is represented by r.
is the carrying capacity.
decreases as resources increase.
is represented by N.

is the carrying capacity.

The maximum rate of growth per individual is:

called carrying capacity.
referred to as logarithmic growth.
the intrinsic growth rate.
represented by K.

the intrinsic growth rate.

The intrinsic growth rate, r, of a population is measured as 0.05. When not limited by resources, the size of this population should:

increase exponentially over time
decrease slowly over time.
stay the same.

increase exponentially over time.

A population of pocket gophers shows logistic growth. As the population approaches carrying capacity (K), the number of individuals added to the population per unit of time will:

increase
decrease
stay the same

decrease

The carrying capacity for a population of birds limited to a specific forest area should increase if you increase:

food availability alone.
nesting site availability alone.
disease or predators alone.
both food availability and nesting sites.
food availability, nesting sites, and disease or predators.

both food availability and nesting sites

A population that is decreasing in size will have an age-structure histogram shaped like a(n):

rectangle, with an (roughly) equal number of individuals in each age group.
diamond, with a wide center depicting a large number of individuals that have reached reproductive maturity.
inverted pyramid, with a narrow base representing a small number of young individuals.
pyramid, with a wide base at the bottom representing a large number of young individuals.

inverted pyramid, with a narrow base representing a small number of young individuals.

The common mud turtle experiences relatively uniform mortality rates throughout its life. It exhibits Type _____ survivorship.

II
I
III

II

_____ describes the number of individuals in a species that survive from one life-cycle stage to the next.

The intrinsic growth rate of a population
A population pyramid
Survivorship
A cohort

Survivorship

Imagine that a lizard inhabits a desert where it has very few natural predators. During a year when resources are scarce, the lizard produces a handful of large eggs rather than several small eggs. This is an example of:

survivorship.
a life table.
mortality.
a trade-off.
a life history.

a trade-off.

T/F K-strategists tend to inhabit "unpredictable" environments and also have population densities near the carrying capacity of an environment.

false

A large population made up of smaller populations linked by migration is a:

habitat patch.
colonization.
island founder event.
metapopulation.

metapopulation.

According to MacArthur and Wilson’s theory of island biogeography, both the land area (size) of an island and the _____ contribute to species diversity.

rock composition of the island
distance of the island from neighboring land masses
depth of the water surrounding the island
climate of the island
proximity of the island to the equator

distance of the island from neighboring land masses

A researcher is comparing the species diversity of two islands. Both islands are roughly equal in size. However, one island is much closer to the mainland. She determines that the S value for the island closer to the mainland is _____ the S value for the island located farther from the mainland. In addition, she finds that the closer island’s extinction rate is _____ the extinction rate on the farther island.

lower than; the same as
lower than; higher than
higher than; lower than
the same as: lower than
higher than; the same as
the same as; higher than

higher than; the same as

Symbiotic relationships are subject to natural selection.

True
False

True

Close interactions that have evolved over time between species are called:

resource partitioning.
interspecific competition.
niches.
metapopulations.
symbioses.

symbioses.

A gardener treats his plants with pesticides, killing any aphids. Once the aphids die, what likely happens to the mutualistic bacteria inhabiting their digestive tracts?

The bacteria would likely die without their mutualistic aphids, as this is an example of an obligate relationship.
The bacteria would likely die without their mutualistic aphids, as this is an example of a facultative relationship.
The bacteria would contribute to the decomposition of dead aphids.
The bacteria would migrate outside of the digestive tract, and survive on the leaves of garden plants.

The bacteria would likely die without their mutualistic aphids, as this is an example of an obligate relationship.

A species that is involved in a facultative mutualism with another:

is reliant on the relationship for survival.
can utilize a variety of different resources.
should quickly develop adaptations in direct response to the other species.
can only interact with that particular species.

can utilize a variety of different resources.

Benefits associated with symbiotic relationships might include all of the following EXCEPT:

nutrients.
shelter.
assistance in reproduction.
protection.
competitive exclusion.

competitive exclusion.

When both participants in a species interaction develop adaptations in direct response to one another, in the long term this could progress into:

coevolution.
resource partitioning.
competitive exclusion.
intraspecific competition.
extinction of one species.

coevolution.

A mutualism in which the survival of one or both participants is dependent on the other is:

obligate.
parasitic.
competitive.
antagonistic.
facultative.

obligate

Measuring its costs and benefits in terms of energy spent and/or gained, mutualism:

is a lose-lose interaction.
results in a gain for one individual and a loss for the other.
None of the answer options is correct.
results in gain for both individuals.
results in a gain for one individual and neither a gain nor a loss for the other.

results in gain for both individuals.

The fact that diverse types of Anolis lizards inhabit (or hunt in) different levels of the tree canopy is the result of the effects of resource partitioning. T/F

true

Imagine that a scientist takes a group of Anolis lizards and introduces them into an enclosure at a research facility in continental South America. He notes that the lizards thrive in this new environment. The fact that Anolis lizards could survive in habitats outside of the Caribbean is a reflection of their _____ niche; their _____ niche is determined by predation and resource availability.

realized; fundamental
fundamental; realized
fundamental; fundamental
realized; realized

fundamental; realized

The _____ of a species is usually the result of predation, competition, and other types of interaction between species.

resource partitioning
fundamental niche
abiotic environment
habitat
realized niche

realized niche

When two species compete for resources, the fitness of:

only the better competitor will increase.
both competitors will remain the same.
both species will decline.
only the poor competitor will decrease.

both species will decline.

Overlap of niches can be minimized through:

resource partitioning.
species evolving similar adaptations over time.
an increase in the similarity of species occupying an area.
reduction in the size of the fundamental niche.
increased population growth.

resource partitioning.

Which factors contribute MOST to intraspecific competition?

a species’ fundamental niche and abiotic surroundings
predation and parasitism
population size
a species’ rate of reproduction and the carrying capacity of the environment
mutualistic relationships

a species’ rate of reproduction and the carrying capacity of the environment

Which of the following is a type of interaction in which BOTH parties are harmed?

competition
mutualism
commensalism
amensalism
predation

competition

Niches are dynamic, and are affected by interactions among species. T/F

true

Which of the following is expected to reduce competition among individuals?

destruction of habitat space
a decrease in the carrying capacity of an environment
a shortened mating season
the disappearance of a predator from an area
resource partitioning

resource partitioning

Measuring its costs and benefits in terms of energy spent and/or gained, which interaction(s) involve(s) one individual gaining and one individual losing?

obligate mutalism
competition
predation
commensalism
facultative mutalism

predation

Which of the following organisms can incorporate atmospheric carbon directly into C6H12O6, thereby playing a major role in a food web?

primary producers
carnivores
consumers
decomposers
grazers

primary producers

Which of the following statements explains how an oxygen-rich atmosphere was possible?

Rates of oxygen consumption were lower than rates of photosynthesis.
All of these choices are correct.
Rates of carbon fixation and respiration have always been equal.
Photosynthetic organisms have existed on earth longer than heterotrophs.
The number of plants has always outnumbered the animals.

Rates of oxygen consumption were lower than rates of photosynthesis.

Which of the following factors likely contributed to the accumulation of O2 within Earth’s atmosphere?

the fact that photosynthesis releases O2 as a product
the fact that oxygen is also cycled during the carbon cycle
the evolution of cyanobacteria
All of these choices are correct.
the fact that there is a slight "de-coupling" between photosynthesis and respiration

All of these choices are correct.

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

Decomposers are vital components of a food web because they:

immediately provide tertiary consumers with usable forms of carbon.
incorporate the carbon contained in atmospheric CO2 into C6H12O6.
serve as primary producers.
return carbon (as CO2) to the atmosphere.

return carbon (as CO2) to the atmosphere.

The evolution of biodiversity on the planet can be linked to patterns in the carbon cycle over time.

False
True

true

Which of the following is a good predictor of biodiversity in terrestrial ecosystems?

predator species in a community
pollinator species in a community
plant species in a community
prey species in a community

plant species in a community

You decide to plant a garden in your backyard. You dig up a strip of grass in a sunny spot. When you have finished digging up the grass, but you haven’t planted anything, you have created a(an) _____ in the lawn.

ecological disturbance
None of the answer options is correct.
ecological disturbance and a new community
new community

ecological disturbance

In the example of the giant kelp forests on the Pacific coast, a rise in the otter population would have what effect on the kelp populations?

Kelp populations would decrease due to increased predation by otters.
Kelp populations would decrease due to an increase in sea urchins.
Kelp populations would increase due to an increase in sea urchins.
Kelp populations would increase due to a decrease in sea urchins.
Kelp populations would be totally unaffected by the otter population.

Kelp populations would increase due to a decrease in sea urchins.

The sum total of the populations that live in a given area is called a(n):

community.
interaction.
ecosystem.
habitat.

community.

Predator/prey relationships are always linear, with one species affecting only one other in the community. T/F

false

Following a disturbance, the process by which species replace each other over time is/are called:

ecosystem engineers.
succession.
disturbances.
keystone species.
competition.

succession.

Keystone species can have significant influences over several populations in a community through their:

avoidance of antagonistic interactions.
large body sizes.
ability to leave their environment relatively unchanged.
effect on high amounts of biomass and energy transfer between populations.
roles as prey species for predator populations in the community.

effect on high amounts of biomass and energy transfer between populations.

While biodiversity includes the number of species in a given area, it also includes:

unique phylogenetic lineages.
amount of primary productivity.
overall number of trophic levels in a food web.
abiotic factors that define the community.

unique phylogenetic lineages.

A species that has a disproportionately large effect on a community is called a _____ species.

central
keystone
engineer
producer
linchpin

keystone

The sequence of species that colonize a recently disturbed area through succession is unpredictable.

False
True

false

A(n) _____ is a community of organisms and the physical environment it occupies.

ecosystem
metapopulation
community
interaction
population

ecosystem

Energy flow through ecosystems can be depicted using a(n):

Calvin cycle.
trophic pyramid.
ecosystem.
food web.
food chain.

trophic pyramid.

While food chains show linear energy transfer between organisms, food webs depict more realistically what occurs in an ecosystem.

False
True

true

The broadest level in a trophic pyramid is primarily composed of:

secondary consumers.
primary producers.
primary consumers.
tertiary consumers.

primary consumers.

What is generally true about biomass and energy as we move from one trophic level to the next?

They both increase.
All of the energy stored initially in organic molecules by the primary producers will be available to the secondary consumers.
Not all energy is transferred to the next trophic level.
Biomass increases but energy decreases.
Organisms at one trophic level always consume all of the resources from the level below them.

Not all energy is transferred to the next trophic level.

Which group in a food web is responsible for returning inorganic compounds back to the environment?

tertiary consumers
decomposers
primary consumers
primary producers
secondary consumers

decomposers

A _____ depicts the flow of carbon through an ecosystem, whereas a _____ depicts the transfer of energy.

food web; niche
food web; trophic pyramid
trophic pyramid, food web
niche; food web

food web; trophic pyramid

Organisms that take up inorganic nutrients and convert them to organic molecules such as carbohydrates and proteins are called:

consumers.
primary producers.
predators.
herbivores.
heterotrophs.

primary producers.

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

more; less
more; more
less; less
less; more

less; more

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

12
6
9
3

6

The high specific heat of water means that land masses near the equator are:

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.

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

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

Temperatures would be hotter.
Temperatures would be colder.
This question can’t be answered without additional information.
Temperatures would remain the same.

Temperatures would be hotter.

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

temperate grassland
temperate coniferous forest
taiga
deciduous forest
savannah

deciduous forest

In either freshwater or marine biomes, which regions would you expect to have the HIGHEST productivity?

just below the deepest level where sunlight penetrates
in the middle depths of the biome
at the deepest depth of the biome
near the surface where sunlight penetrates

near the surface where sunlight penetrates

In deeper waters, nutrients primarily come from:

surface winds creating deep ocean currents.
glacial ice melt.
thermal vents.
detritus from more productive shallower waters.

detritus from more productive shallower waters.

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

continents
biomes
countries
latitudes

biomes

This biome is the coldest, with the lowest biodiversity and a permanent layer of ice beneath the soil.

taiga
tundra
temperate coniferous forest
alpine
savanna

tundra

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?

tundra
chaparral
savannah
alpine
desert

desert

Most of Earth’s primary production comes from tropical rainforests. T/F

false

In marine ecosystems phosphorus is added to the ecosystem primarily from:

erosion of rocks on land.
fixation of atmospheric phosphorus.
glacial ice melt.
dead organisms that fall to the bottom of the ocean.

erosion of rocks on land.

Why are microorganisms like fungi, bacteria, and archaeons so important to the carbon cycle?

These microorganisms form their own portion of the carbon cycle in case other areas of the carbon cycle fail.
These microorganisms generate the oxygen necessary for aerobic organisms.
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.

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

nitrifying bacteria.
nitrogen-fixing bacteria.
denitrifying bacteria.
All of these choices are correct.

denitrifying bacteria.

If phosphorus concentrations were to suddenly increase in a marine ecosystem, which of the following would likely occur?

decreased primary productivity
increased primary productivity
no change in the rate of primary productivity

increased primary productivity

In which of the following regions would you expect to find river biomes with HIGH levels of oxygen in the water?

slow-moving, clear-water rivers in the Rockies
fast-moving, muddy rivers in the Amazon
slow-moving, muddy rivers in the Amazon
fast-moving, clear-water rivers in the Rockies

fast-moving, clear-water rivers in the Rockies

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

nitrogen; amino acids
carbon dioxide; inorganic molecules
carbon dioxide; energy
nitrogen; energy

…

Ultimately, the nitrogen cycle is dependent on:

nitrogenous waste production in different environments.
addition of fertilizers to the soil.
microorganisms that convert atmospheric N2 into usable forms.
respiration rates of heterotrophs.

microorganisms that convert atmospheric N2 into usable forms.

Which of the following statements reflects an evolutionary change that is in line with the Red Queen hypothesis?

a species of beetle that switches to production of offspring solely through parthenogenesis
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 has two new mutations that confer resistance to an insecticide

a species of beetle that goes extinct when farmers start spraying insecticide

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

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 nitrogen levels in the area
high oxygen levels in the area
high carbon dioxide levels in the area
high phosphate levels in the area

high nitrogen levels in the area

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

global warming.
eutrophication.
the greenhouse effect.
ocean acidification.

eutrophication.

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 consume oxygen via aerobic respiration.
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 population growth of 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.

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

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 support greater numbers of sharks.
Higher productivity may support greater diversity of phytoplankton species.
Higher productivity may result in increased respiration on sinking algal material, depleting oxygen within gulf waters.
The nutrient runoff depletes nitrate, which cannot be made industrially.

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

Eutrophication describes the:

increased production of crops using fertilizer.
process in which added nutrient levels lead to the growth of algae and cyanobacteria populations, eventually causing oxygen availability to decline.
total amount of nitrogen fertilizer that leaves agricultural fields as surface runoff.
death and decomposition of algal blooms.

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

Increased phosphate levels in the Everglades has led to:

displacement of native plants by phosphate-loving introduced plants.
increased plant growth and diversity.
declining populations of low-phosphate adapted cattails.
eutrophication followed by declines in fish and alligator populations.
expansion of native plants into adjacent ecosystems.

displacement of native plants by phosphate-loving introduced plants.

Increased phosphate levels in the Everglades has led to:

displacement of native plants by phosphate-loving introduced plants.
increased plant growth and diversity.
declining populations of low-phosphate adapted cattails.
eutrophication followed by declines in fish and alligator populations.
expansion of native plants into adjacent ecosystems.

displacement of native plants by phosphate-loving introduced plants.

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?

A decrease in beef production near the researchers’ sampling area.
The failure of rice paddies to be established in Alaska, given its climate.
None of the answer options is correct.
The melting of permafrost accompanied by the thawing of methane-producing bacteria.
The release of methane from thawed permafrost.

The release of methane from thawed permafrost.

What is the approximate size of the human population today?

7 billion people
10 billion people
25 billion people
5 billion people
2 billion people

7 billion people

An individual’s ecological footprint is equivalent to the:

All of these choices are correct.
amount of land required to provide all the resources used by that individual.
total amount of energy used by that individual.
total amount of carbon emissions from that individual’s car.
total amount of food consumed by that individual.

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

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

As the standard of living decreases, the ecological footprint increases.
It depends on country—in developed countries, the ecological footprint and standard of living are positively correlated; in developing countries, they are negatively correlated.
None of the answer options is correct.
As the standard of living increases, so does the ecological footprint.
It depends on the country—in developing countries, the ecological footprint and standard of living are positively correlated; in developed countries, they are negatively correlated.

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

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.

keystone
native
invasive

invasive

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 decline of prey species
no change in marine communities
population growth of prey species

population growth of prey species

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

true

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
birds
insects
mammals
fish

amphibians

Sustainable development plans are designed to allow:

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

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 generate income when people visit to see the biodiversity protected in the reserve.
will not change over time so all the species will be conserved as long as the reserve exists.
that is designed for a single species will also protect other species in the reserve.

…

Increased overfishing on predators of crown-of-thorns starfish is likely to result in continued increase in crown-of-thorns starfish population sizes.

True
False

true

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 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 many politicians are biologists and they can influence government policy.
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 if we don’t count all the species on the planet, then we won’t be able to identify more potential sources of food.

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).

Genetic variation within species is important to conservation because:

genetic variation provides material for natural selection to "act upon" in changing environments.
species with low genetic variation go extinct.
high levels of genetic variation will result in more populations’ speciating, so biodiversity will be maintained.
low levels of genetic variation may make hybrid species more likely, so neither species will go extinct.

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

Recall that photosynthetic rates remain relatively constant in regions near the equator. Imagine that tropical environments persisted throughout Earth’s northern and southern hemispheres (i.e., Earth’s entire climate mirrored that near the equator). If Keeling had collected his atmospheric CO2 data on such an Earth, what would you expect the Keeling Curve to look like?

a sinusoidal curve sloping downward (atmospheric CO2 levels would fluctuate seasonally, but would have decreased over time)
a straight line sloping downward (atmospheric CO2 levels would not seasonally oscillate, but would have decreased over time)
a straight line without a slope (atmospheric CO2 levels would have remained constant over time)
a sinusoidal curve sloping upward (atmospheric CO2 levels would fluctuate seasonally, but would increase over time)
a straight line sloping upward (atmospheric CO2 levels would not seasonally oscillate, but would have increased over time)

a straight line sloping upward (atmospheric CO2 levels would not seasonally oscillate, but would have increased over time)

The CO2 level is _____ during winter in the northern hemisphere compared to levels in the summer.

lower
the same
higher

higher

Measuring the isotopic composition of atmospheric CO2 shows that the burning of fossil fuels has led to _____ CO2 levels over the last 200 years.

increasing
decreasing

increasing

Which of the following processes are typically associated with the short-term carbon cycle? (Select all that apply.)

photosynthesis
respiration
plate tectonics
chemical weathering

photosynthesis respiration

Recall that during the Paleozoic Era, atmospheric CO2 levels decreased. Why?

Photosynthetic, woody plants first appeared during this period.
Volcanism decreased during this period.
New, extensive mountain ranges formed and chemical weathering decreased.
Earth’s plate tectonics changed dramatically, and subduction increased.

Photosynthetic, woody plants first appeared during this period.

The rate of exchange of carbon between the atmosphere and the oceans represents a carbon:

biomass.
flux.
sink.
reservoir.
precipitation.

flux.

The _____ cycle deals with geological processes and carbon reservoirs, some of which have been built up (or take place) over a period of millennia. In contrast, the _____ cycle involves biological processes that are carried out on a daily and/or seasonal basis.

short-term carbon; long-term carbon
long-term carbon; intermediate carbon
long-term carbon; short-term carbon
short-term carbon; rapid carbon

long-term carbon; short-term carbon

Increased rate of photosynthesis is the most likely explanation as to why atmospheric CO2 levels appear lowest during glacial periods of Earth’s history. T/F

false

The long-term and short-term carbon cycles are connected by the fact that some of the carbon contained in C6H12O6 (or other organic molecules) in plants is incorporated into sedimentary rocks or oil; it is not immediately reintroduced back into the atmosphere. T/F

true

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

None of the answer options is correct.
expansion of rice farming
capturing CO2 in smokestacks (using smokestack scrubbers)
using iron and other supplements to fertilize the ocean (increase phytoplankton biomass)
reforestation of previously cleared landscapes

reforestation of previously cleared landscapes

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

exponential
logistic
a combination of both

logistic

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:

intermediate elevations.
higher elevations.
None of the answer options is correct.
unpredictable elevations—the precise response would depend on individual species, with no clear trends or averages.
lower elevations.

higher elevations.

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

1-3°C.
2-5°C.
5-7°C.
7-10°C.
12-15°C.

2-5°C.

Which of the following statements is TRUE regarding the process of eutrophication?

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

It can result in "dead zones" devoid of aquatic animal life.

In addition to burning fossil fuels, humans return CO2 to the atmosphere faster than it can be removed by:

expanding rice production.
polluting the oceans.
clearing forests for agriculture.
generating nutrient pollution.

clearing forests for agriculture.

Which of the following statements about coral bleaching is TRUE?

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

All of these choices are correct.