Science 8--Chapter 5:2 Cycling of Materials

Nitrogen gas

After decomposers return nitrogen to the soil, bacteria transform a small amount of the nitrogen into _______________ _____________, which then returns to the atmosphere to complete the nitrogen cycle.

Build proteins

All organisms need nitrogen to _____________ _______________, which are used to build new cells.

Accumulate, sediment

Because many phosphate salts are not soluble in water, they sink to the bottom and ____________________ as ________________.

Air, water, and living organisms

Carbon exists in _______________,________________, and ____________________.

Proteins, fats, carbohydrates

Carbon is the essential component of __________________, ______________________ and. ____________________, which make up all organisms.

Fats, oils, other molecules

Carbon stored in the bodies of organisms as ___________, _______________, or _________________ ________________, may be released into the soil or air when the organism dies.

Fossil fuels

Coal, oil, and natural gas are known as ___________________ _________________.

Carbon

Consumers obtain ____________________________ from carbohydrates in the producers that they eat.

Acid parcipitation

Dissolved in rain or snow, the nitric acid falls as _____________. __________________.

Carbon Dioxide

During cellular respiration, some of the carbon is released back into the atmosphere as _______________ ______________.

Oxygen

Excess algae can deplete an aquatic ecosystem of important nutrients such as ________________. On which fish and other aquatic organisms depend.

Rapid growth of algae, algal bloom

Excess nitrogen and phosphorus can cause __________ ___________ __ __________, __________ ____________.

Runoff

Excessive amounts of fertilizer can enter terrestrial and aquatic ecosystems through ____________________)))

Carbon

Fossil fuels store ________________ left over from bodies of organisms that died million of years ago.

Increase in the temperature

Global warming is an ________________ ____ _______ _____________________ of the Earth.

Nitric acid

In the air, nitric acid can combine with oxygen and water vapor to form _____________ ______________),

Global warming

Increased levels of carbon Dioxide may contribute to __________________ _____________________.

78

Nitrogen makes up ___________ of the gases in the atmosphere.

Altered, fixed

Nitrogen must be ______________ or ______________, before organisms can use it.

Brazil

One of the largest carbon sinks is located in _____________________.

Bacteria, atmospheric nitrogen

Only a few species of ___________________ can fix ___________________ ______________________ into chemical compounds that can be used by other organisms.

Rocks

Phosphorus may enter soil and water when _____________ erode.

Absorb, roots

Plants ______________ phosphates in the soil through their ____________.

Soil, water eating plants, other animals

Plants get the phosphorus they need from ______________ and ____________, while animals get their phosphorus by ________________ ___________ or ______________ ___________ that have eaten plants.

carbon dioxide (CO2)

Producers convert _________________ _________________ in the atmosphere into carbohydrates during photosynthesis.

Phosphate

Small amounts of phosphorus dissolve as ____________), which moves into the soil.

Limestone, "carbon sinks"

Some carbon is stored in ________________________, forming one of the largest _________________ ______________ on Earth.

Washes, ocean

Some phosphorus ________________ off the land and ends up in the ________________.

The Carbon Cycle

Study the diagram

Phosphorus cycle

The _______________ ___________ is the cyclic movement of phosphorus in different chemical forms from the environment to organisms and then back to the environment.

nitrogen cycle

The _______________ _____________is the process in which nitrogen circulates among the air, water,plants,,and animals in an ecosystem.

Carbon cycle

The ________________ _______________ is the movement of carbon from the nonliving environment into living thinggs and back

Nitrates

The bacteria use sugar provided by the legumes to produce nitrogen -containing compounds such as _____________________.

Carbon Dioxide

The carbon returns to the atmosphere as _____________ _____________.

Legumes

These bacteria live within the roots of plants called ________________, which include beans, peas, and clover.

Coal, oil,natural gas

These molecules may form deposits of _____________, ______________, or _____________________.

Nitric oxide

When fuel is burned, large amounts of ______________ ___________ is released into the atmosphere.

Humans

________________ burn fossil fuels, releasing carbon into the atmosphere.

Phosphorus

__________________ is an element that is part of many molecules that make up the cells of living organisms.

Fertilizers

__________________, which people use to stimulate and maximize plant growth, contain both nitrogen and phosphorus.

Nitrogen, nitrogen cycle

____________________ stored within the bodies of living things is returned to the ________________ ______________ once those organisms die.

Nitrogen-fixing bacteria, ammonia

_____________________-___________________ _______________are the only bacteria that can convert atmospheric nitrogen into __________________________.

Decomposers

_________________________ break down decaying plants and animal, as well as plant and animal wastes.

Lightning

_________________________ converts some atmospheric nitrogen into nitrates that organisms can use.