Practice test ch 5

The sum total of the planet’s living organisms and abiotic systems is ________.

an ecotone
a biome
the biomass
the biosphere

the biosphere
The biosphere includes the planet’s living organisms and where they live. It includes the biotic and abiotic systems with which they interact.

hint: Reread the section called “Earth’s Environmental Systems.”

When considering the phosphorus cycle, plants obtain most of their phosphorus from _______.

rocks and soils
phosphorus-fixing bacteria
detritivores
gases absorbed from the atmosphere

rocks and soils
Most phosphorus comes from rocks, soils, and fertilizers that are made from rocks. Phosphates are leached from rock by water.

hint: Where is most of the phosphorus on Earth stored?

Which of the following best characterizes the factors that have contributed to the “dead zone” in the waters of the Chesapeake Bay for the past few decades?

fertilizer runoff from farms, animal manure, and stormwater runoff
increasing oil spills in the Chesapeake Bay
gasoline spillage from the refineries
the farm practices around the Chesapeake Bay

fertilizer runoff from farms, animal manure, and stormwater runoff
The nitrogen levels of the water have increased so that bacterial activity has reduced oxygen levels dramatically

hint: What does eutrophication mean?

A metapopulation is ______________.

a really big population
a network of separate populations with some interbreeding between them
a population that is undergoing exponential growth
a population that spans two biomes

a network of separate populations with some interbreeding between them
Since the populations are mostly separate, they are not really a single population, but because there is interbreeding between them, they are not completely separate. They are therefore referred to as a metapopulation.
The largest reservoir of carbon in the carbon cycle is in sedimentary rock that may take hundreds of millions of years to return to the living portion of the cycle. What is the second largest reservoir of carbon?

the oceans
the atmosphere
fossil fuels
living things

the oceans
Fossil fuels are a large reservoir and a large concern, since humans are removing carbon from this reservoir and adding it to the atmosphere, but it is small compared to another one of the answers.
What does the term emergent properties describe?

characteristics that are not evident in the system’s individual components but are evident only by looking at the whole operating system
the characteristics of emerging vegetation such as the forb called fireweed
the particular timing and season of emergence of flowers in the spring, as long as timing of the emergence of flowers is not being changed by global climate change
the particular timing and season of emergence of organisms from dormancy

characteristics that are not evident in the system’s individual components but are evident only by looking at the whole operating system
An emergent property of a tree is that it may be used by birds for building nests, something that is not apparent just by knowing the parts of a tree.

hint: Reread the section called “Earth’s Environmental Systems.”

We will write a custom essay sample on
Any topic specifically for you
For only $13.90/page
Order Now
How do plants contribute to the water cycle?

through the process of infiltration
through the process of transpiration
through the process of condensation
through the evaporation of water from their roots

through the process of transpiration
Transpiration is a process that helps pull water from the roots, up the stems, and through the leaf. The sun’s energy helps to break the hydrogen bonds holding the water molecules together.

hint: What is the process of water moving through plants and trees called?

Ecosystems that convert solar energy to biomass rapidly ________.

are usually found in cold, damp climates where decomposition is slow
are said to have high secondary productivity
have little vegetation
are said to have high primary productivity

are said to have high primary productivity
The more rapidly photosynthesis makes more biomass, the higher the primary productivity.
The process that makes nitrogen available to plants by mutualistic and free-living bacteria is called __________.

decomposition
ammonification
nitrogen fixation
decomposition

nitrogen fixation
The rhizobia bacteria live in root nodules. The plant supplies them with a habitat in which to live, water, and nutrients, and the bacteria supply nitrogen for making plant proteins.

hint: What process do bacteria help continue in regard to nitrogen?

Positive feedback loops _______.

are loops in which inputs reverse a change that may cause damage to an ecosystem
are relatively common in nature compared to negative feedback
are more common in natural systems altered by human actions
result in stabilizing concentrations of a substance

are more common in natural systems altered by human actions
If the input and output are reversed, it is a negative feedback loop.
The structural sphere of Earth that is best described as the rocks and sediment is the ______.

hydrosphere
atmosphere
lithosphere
biosphere

lithosphere
The lithosphere consists of the rock and sediment, and the planet’s uppermost mantle and crust.

hint: What are the structural spheres of Earth?

A landscape ecologist would be most likely to study ______.

how a cactus can survive for months without any rain
the movement of nutrients from alpine grassland on a mountain through the temperate deciduous forest at the lower elevations into the tropical rain forest at the base
the multiple trophic levels found in a freshwater lake
the mutualistic interaction between an acacia tree and the ants that live in it and the predatory interaction between the ants and the insect species trying to eat the acacia

the movement of nutrients from alpine grassland on a mountain through the temperate deciduous forest at the lower elevations into the tropical rain forest at the base
Landscape ecology looks at the interactions between multiple ecosystems.
Nitrogen availability is often a limiting factor in plant growth. Nitrogen tends to be scarce because __________.

There is very little nitrogen present in the atmosphere.
Fossil fuel combustion uses the available nitrogen; what is left for the plants is not enough, making the fuel combustion a limiting factor.
Nitrogen gas (N2) is so stable that only a few organisms are capable of turning it into nitrogen that can be used for living things.
Decomposers are unable to recycle nitrogen, meaning that all nitrogen used must be produced by bacteria.

Nitrogen gas (N2) is so stable that only a few organisms are capable of turning it into nitrogen that can be used for living things.
Most of the nitrogen used by living things is recycled through decomposers.

hint: What pathways of nitrogen fixation are available?

Which best describes how energy and nutrients work in an ecosystem?

nutrients flow through an ecosystem; energy cycles
energy flows through an ecosystem; nutrients cycle
because energy is stored as carbon compounds, energy and nutrients are the same thing
energy and nutrients are both recycled in ecosystems

energy flows through an ecosystem; nutrients cycle
Energy is lost to the ecosystem as heat so it cannot be recycled. The planet is a closed system to nutrients; they must be recycled.

hint: What happens to energy and nutrients when they move through the ecosystem? How are they different?

In the carbon cycle, carbon moves from the atmosphere into the living portion of the cycle through ______.

photosynthesis
burning of fossil fuels
respiration
sedimentation

photosynthesis
Photosynthesis by green plants, algae, and cyanobacteria takes carbon from the atmosphere and turns it into living material.

hint: Do plants or do animals use carbon dioxide for energy processing?

Which of the following would destabilize an ecosystem?

positive feedback loops
homeostasis
stable populations
negative feedback loops

positive feedback loops
During positive feedback increased output in a system leads to increased input. This can be incredibly destabilizing for a system. Luckily this is found rarely in nature, but it is happening more and more often in systems that humans are affecting.

hint: Which of the answers is detrimental to an ecosystem rather than a stabilizing factor

A contributing factor in the process of eutrophication is ______.

lack of nutrients
nitrogen and phosphate pollution
stable populations
acid rain

nitrogen and phosphate pollution
How is this the opposite of what happens in the eutrophication process?

hint: What is eutrophication, and what steps lead to the final result of hypoxic waters?

Which of the following would be considered an emergent property of a tree?

its roots
its chloroplasts
its role as a habitat for other organisms in the ecosystem
its leaves

its role as a habitat for other organisms in the ecosystem
Chloroplasts are organelles inside the leaves of a tree. They are a component part of a tree, not an emergent property.
Net primary production in an ecosystem can be calculated by ______.

multiplying productivity by secondary production
subtracting macronutrients from micronutrients
adding primary production to secondary production
subtracting respiration from gross primary production

subtracting respiration from gross primary production
Gross primary production (production by autotrophs) minus the energy used in the process of cellular respiration (by autotrophs) equals the amount of energy available to a system.

hint: What is net primary production, and what factors determine it?

A(n) _____ is an example of an ecosystem with high primary productivity while a _____ is an example of an ecosystem with low primary productivity.

open ocean, wetland
tundra, coral reef
desert, tundra
algal bed, desert

algal bed, desert
An algal bed can convert solar energy to biomass energy very quickly and thus has high primary productivity while the desert organisms do not convert solar energy to biomass energy very quickly and therefore have low primary productivity.

hint: Ecosystems with what important characteristic tend to have the highest net primary productivity?

_____ is an example of a resource provided by our ecosystems, while _____ is(are) an example of a service provided by our ecosystems.

Wind, windmills
Water, water cycling
Crude oil, oil refineries
Salt water, fresh water

Water, water cycling
Water is a resource, and the ability of an ecosystem to purify water and return it to Earth in the water cycle is a service that the ecosystem provides for us, free of charge.

hint: What is a resource and how is it different from an ecosystem service?

Which of the following statements about dead zones is correct?

Dead zones occur in terrestrial ecosystems.
Dead zones occur in the arctic tundra.
Dead zones are reversible if nutrient pollution input to a system is reduced.
Dead zones, once they exist, are permanent.

Dead zones are reversible if nutrient pollution input to a system is reduced.
Examples of the reversal of hypoxic waters have been seen in New York City and the former Soviet Union.

hint: What is a dead zone, and what leads to such a situation?

Some of the most ancient water on Earth can be found in ________.

aquifers
the ocean
the Great Lakes
streams

aquifers
Aquifers hold groundwater for a long time, and since this water is not exposed to the air, evaporation cannot occur.

hint: What type of reservoir of water is not exposed to evaporation?

Which of the following processes was responsible for humans increasing nitrogen’s flux from the atmosphere to Earth’s surface?

the Haber-Bosch process
the carbon-nitrogen extraction process
photosynthesis
bacterial denitrification

the Haber-Bosch process
This process allowed people to overcome the lack of nitrogen available by natural nitrogen fixation by producing ammonia on a large scale

hint: Reread the section called “Biogeochemical Cycles,” particularly the portion about the nitrogen cycle.

All of the following are considered reservoirs of carbon except ______.

plants
phosphorus
the oceans
sediments

phosphorus and sediments
Plants are a reservoir for carbon because they take in a large amount of carbon dioxide in the process of photosynthesis.

hint: Where can carbon be stored on Earth temporarily?

Which of the following describes a negative feedback loop?
It drives a system toward an extreme.
It stabilizes the system.
It causes the system to move in one direction at a time.
It is rare in nature.
it stabilizes the system
Which of the following statements is NOT correct?
A system is a network of relationships among various components.
In a dynamic equilibrium, system processes move in opposing directions to balance their effects.
A system in homeostasis is not able to maintain constant (stable) internal conditions.
A system with emergent properties has characteristics that are not evident in the components alone.
A system in homeostasis is not able to maintain constant (stable) internal conditions.
Which of the following is a correct statement?
Energy and matter flow in one direction only.
Energy and matter both cycle repeatedly.
Energy flows in one direction, while matter recycles.
Matter flows in one direction, while energy recycles.
Energy flows in one direction, while matter recycles.
What is the definition of secondary production?
Biomass generated by heterotrophs from consuming autotrophs
Elements and compounds that are required for survival
Energy remaining after respiration that is used to generate plant biomass
Assimilation of energy by autotrophs
Biomass generated by heterotrophs from consuming autotrophs
Which biogeochemical cycle uses photosynthesis and respiration to cycle its atoms?
Carbon
Nitrogen
Water
Phosphorus
Carbon
Which biogeochemical cycle is being affected by increased fertilizer production through the Haber-Bosch process?
Carbon
Nitrogen
Water
Phosphorus
Nitrogen
Which of the following is NOT a way to decrease hypoxia in estuaries and coastal oceans?
Reduce fertilizer use on farms and lawns
Apply fertilizer during heavy spring rains
Restore wetlands
Improve sewage treatment technologies
Apply fertilizer during heavy spring rains

would cause even more nutrients

Which of the following ecosystem services do you think is the most important?
Providing services such as water purification
Providing goods such as food
Enhancing the quality of our lives, such as spiritual renewal
All of these are fundamentally important.
any
The eutrophication that has taken place in Chesapeake Bay, the Gulf of Mexico, and other locations appears to be due to ________.

global warming from human use of fossil fuels
pesticide use along the waterways
heavy metals dumped in the sewage
weather alone, because it is only obvious in the summer
excess nutrients from fertilizers

excess nutrients from fertilizers
Trophic Levels (2 of 2)

This energy pyramid illustrates the inefficiency of energy transfer in many systems. On average trophic levels pass on only 10% of their energy to the next trophic level.
If the amount of energy in the primary producers in this system is 980 kcal, how much energy will be available in the secondary consumers?

9.8

On average, 10% of energy is transferred from one trophic level to the next. The question gives you the amount of energy in the primary producers, and asks the amount of energy in secondary consumers.

Step 1: Calculate the amount of energy in primary consumers.

To calculate 10% of 980 kilocalories, convert 10% to the decimal 0.10, and then multiply 980 by 0.10 to get 98 kilocalories.

Or you can set up a ratio, cross multiply and solve for X:

Step 2: Calculate the amount of energy in secondary consumers.

Primary consumers contain 98 kilocalories (see step 1) and only 10% goes on to the secondary consumer level.

To calculate 10% of 98 kilocalories, convert 10% to the decimal 0.10, and then multiply 98 by 0.1 to get 9.8 kilocalories.

Or you can set up a ratio, cross multiply and solve for X:

Population Growth (3 of 3)

You have been assigned to help manage a population of white-tailed deer. You are researching the data and find that the population roughly follows the logistic pattern of population growth and has a carrying capacity of 500 individuals.

Indicate the point on the graph that represents the population size (N) at which population growth begins to slow.

This point is located where the curvature changes from positive (curving up) to negative (curving down); it is called the “inflection” point. It represents the population size above which adding more individuals causes population growth to slow. Individual are being added, but fewer individuals are being added per existing individual.

In many managed species such as fish, lobster, and even deer, this value is important for determining levels of sustainable harvest. Many managers choose this population size as the target for sustainability. They harvest individuals above this number, as this is the point at which more individuals slow the populations’ growth rate.

Harvesting lower than this number would remove individuals that contribute to the fastest growth. The inflection point is where the effects of density dependent regulation begins.

The inflection point indicated is the point of most rapid population growth.