Water land ecology test 2 study set

Recall that areas with high net primary productivity not only take up large amounts of CO2 and give off large amounts of oxygen, but also produce high levels of biomass rapidly that eventually die off. What is the likely result of the increasing amounts of fertilizers in the major rivers emptying into oceans?

Eutrophication, followed by hypoxia, is a likely result, ultimately leading to less CO2 uptake and less oxygen released.

In an aquatic ecosystem experiencing eutrophication, levels of dissolved macronutrients ________ and dissolved oxygen levels ________.

increase; decease

The precipitation that flows over land and enters waterways is ________.

runoff

________ is any network of relationships among a group of components that interact with and influence one another through the exchange of energy, matter, or information.

system

A system stabilized by negative feedback, with opposing processes offsetting each other, is said to be in ________.

dynamic equilibrium

In some areas, cattle on an open range may compact fragile soils while grazing. This can damage plant roots, leading to fewer, smaller plants, which may in turn cause cattle to graze more and work harder to obtain food. This is an example of a ________.

positive feedback loop

The biosphere is best defined as ________.

all Earth's organisms and the nonliving environment with which they interact

Negative feedback processes tend to function within ecosystems to ________.

stabilize the ecosystem

All of the following are considered Earth's structural spheres except the ________.

atmosphere

Nitrogen and phosphorus are referred to as macronutrients because ________.

they are required in large amounts for organisms to survive

Ecotones are the ________.

transitional zones between ecosystems

When a reservoir accepts more material than it releases, this is known as a(n) ________.

sink

Which statement best describes the relationship between temperature and productivity of terrestrial biomes?

Warmer biomes tend to have higher productivity than colder biomes, given sufficient moisture.

Which of the following describes matter and energy flow in an ecosystem?

Energy flows through an ecosystem, whereas matter is recycled within an ecosystem.

The largest pool of carbon in the carbon cycle is ________.

the ocean

The atmosphere is an important reservoir (pool) in all the following cycles except ________.

phosphorus

All of the following are fluxes in the hydrologic cycle except ________.

fixation

The majority of Earth's fresh water exists ________.

in the form of ice

The first essential step in changing atmospheric nitrogen into more usable NH3 is called ________.

nitrogen fixation

Which of the following factos drives TFR down?

Social and economic security

Zero population growth occurs in a population when

Birth rate equals death rate and there is no migration

According to the IPAT model, which of the following would most likely reduce the environmental impact of a society?

Greater use of birth control by most members of society

A population that is neither growing nor declining will have a TFR of

2.1

Demographic transition

the decline in death rates and subsequent decline in birth rates that occur as a country economically develops

Humus

the organic soil component that holds soil moisture and enhances soil fertility

Traditional agriculture

refers to the agricultural practices in which the members of a farming family do not make use of large-scale irrigation, chemical fertilizer, machinery, or technology.

Leaching

Removes water-soluble nutrients from topsoil

The horizon where leached minerals and organic matter accumulate is called the

B horizon

Compaction of soil in a garden harms plants by

decreasing aeration, decreasing infiltration, and increasing runoff

Desertification

the loss of more than 10% of soil productivity in arid areas due to such factors as erosion, soil compaction, overgrazing, and forest removal

Shelterbelts are to ________ as terraces are to ________.

wind erosion; water erosion

Salinization

the buildup of salts in soils, often as a result of overirrigation.

Contour farming

is a method of reducing soil erosion by plowing furrows sideways across a hill that follows the natural shape of the land.

Erosion can result in a positive feedback loop because

plants are less likely to grow in eroded soil

The sequence for creating a Genetically modified organism

• plasmid is isolated from a strain of bacteria.

• The gene of interest is isolated from the cell of an organism

• The gene of interest is inserted into a plasmid

• The plasmid containing the recombinant DNA is inserted into bacteria

• The bacteria containing the recombinant DNA are allowed to reproduce

• The gene is transferred to the target organism

Raising which of the following requires the least land and water per kilogram of protein produced?

Eggs and chicken

what is IPM?

• integrated pest management

  • combination of multiple strategies that maximize pest control while reducing impacts

What accounts for half of the world’s GM crops

Soybeans

Approximately ________% of the food we consume comes from ________ crop species.

90; 15

Aquaculture

• The cultivation of aquatic organisms in controlled environments

  • can bring economic benefits and food security to many developing regions

Why have most bioengineered crops been modified for "resistance" traits?

These traits have the economic potential to save on production costs.