APES Unit 02 Test: Ecosystems

Study guide for APES Unit 2 Test

Humans are

omnivores

In an ecosystem, almost all of the incoming energy will eventually be

radiated from Earth as heat energy

The very necessary process of breaking down the dead bodies of organisms is a function of

detritivores

What does a decrease in salmon population do to the building of dams that obstruct their migration up rivers to spawn represent?

an abiotic factor affecting a biotic factor

The hydrologic cycle is a way nature renews water quality

True

All physical forms of water (solid, liquid, and gas) on or near the Earthʻs surface make up the

hydrosphere

Which statement about microorganisms is true?`

Bacteria and other microbes help purify the water we drink.

What term describes groups of different species living together in a particular place with a potential for interacting with one another?

community

What is a primary link between photosynthesis and aerobic respiration?

carbon

Ecology is the study of

how organisms interact with each other and the nonliving environment

The exchange of matter through the ______ is called the biogeochemical cycle

biosphere

What is the innermost layer of the atmosphere, extending 17 kilometers above sea level at the tropics and about 7 kilometers above the Earthʻs North and South poles?

troposphere

The hydrosphere is the Earthʻs intensely hot core, thick mantle composed mostly of rock, and thin outer crust.

False

____________________ can help scientists understand large and very complex systems by allowing them to change variables and project possible changes.

Simulations

How much of the Earthʻs water supply is available as accessible liquid freshwater?

0.024%

10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.

10

Each trophic level in a food chain or food web contains a certain amount of organic matter, called ____.

biomass

The energy flow through the trophic levels of an ecosystem is represented as a pyramid because __________.

only about 10% of the energy at each trophic level is available at the next level

Life on Earth depends on the interaction of gravity, the cycling of matter, and the ____.

one-way flow of high-quality energy

Complex networks of interconnected food chains are ____.

food webs

If grass stores 1,000 energy units received from the sun, the ecological efficiency of the ecosystem is 10%, and the trophic levels are grass → cow → human, how many units of energy does the human receive of the original 1,000 units?

10

A cow eating grass is an example of a _____.

primary consumer

Aerobic respiration requires ____.

glucose and oxygen

What is the primary source of energy for nearly all of Earthʻs ecosystems?

sunlight

Why are most energy pyramids limited to three to five levels?

There is insufficient energy to support more trophic levels.

Approximately what percentage of the visible light that reaches Earthʻs producers is converted to chemical energy?

1%

A human who just ate a hamburger is eaten by a shark while swimming. The shark is acting as a _____.

tertiary consumer

In ecosystems, organisms at the highest trophic levels usually contain less collective biomass than the organisms at lower trophic levels because __________.

organisms are inefficient at converting the energy they consume to biomass

The oceans of the Earth cover approximately what percentage of the Earthʻs surface?

71%

What is one way in which energy flow differs from chemical cycling?

Energy flow is unidirectional; chemical elements can be recycled.

In general, the biomass in an ecosystem will be greatest at the trophic level comprising _____.

producers

In an ecosystem, the __________ is always greater than the __________.

energy used by primary consumers … energy used by secondary consumers

What is an end product of anaerobic respiration?

carbon dioxide

Which terrestrial ecosystem or life zone produces the lowest net primary productivity per year?

extreme desert

Despite a low net primary productivity (NPP), which ecosystem or life zone produces the most biomass each year?

open ocean

In hundreds of years, we have released large quantities of fossil fuels that took millions of years to form.

True

Which of the following is abiotic?

a rock

Methane, CO₂, and water vapor make up about 30% of the Earthʻs troposphere.

False

Phosphorus is an example of which of the following types of abiotic factors?

nutrients

The global water cycle supports a net flow of atmospheric water vapor __________.

from the oceans to land

The hydrologic cycle is the movement of ____.

water

Ammonia that is not taken up by plants may undergo ____.

nitrification

Nitrogen gas, the major component of the atmosphere, cannot directly be used by plants and animals.

True

Phosphate pollution of lakes and rivers __________

can cause algal blooms that can kill most aerobic organisms in a lake

Nitrogen gas makes up nearly 80% of Earthʻs atmosphere, yet nitrogen is often a limiting factor for plant growth. Why?

The atmospheric form of nitrogen cannot be used by plants.

The phosphorus cycle lacks a(n) _____ component.

atmospheric

Nutrient cycles connect past, present, and future forms of life.

True

Hydrogen sulfide and sulfur dioxide are added to the atmosphere by ____.

volcanoes

The hydrologic cycle is driven primarily by ____.

solar energy