Biology Chapter 3 Section 3

What are the three nutrient cycles that play especially prominent roles in the biosphere? (p76-79)

1. Carbon Cycle 2. Nitrogen Cycle 3. Phosphorus Cycle

What are nutrients? (p76-79)

> All the chemical substances that an organism needs to sustain life are its nutrients. > Every living organism needs nutrients to build tissues and carry out essential life functions. > Similar to water, nutrients are passed between organisms and the environment through biogeochemical cycles.

Why is carbon especially important to living systems? (p76-79)

> Carbon is a key ingredient of living tissue. > Biological processes, such as photosynthesis, respiration, and decomposition, take up and release carbon and oxygen.

How is the movement of matter through the biosphere different from the flow of energy?

> Energy and matter move through the biosphere very differently. > UNLIKE THE ONE-WAY FLOW OF ENERGY, MATTER IS RECYCLED WITHIN AND BETWEEN ECOSYSTEMS. > Biogeochemical Cycles

What are three large reservoirs where carbon is found in biosphere? (p77)

> oceans, > air, > certain types of rocks.

Which of the following statements about the phosphorus cycle are true? (p79) a. Phosphate is released as rocks and sediments wear down. b. Plants absorb phosphate from the soil or from water. c. Phosphorus is abundant in the atmosphere. d. Organic phosphate cannot move through food webs.

A and B

Why do blooms occur? (p80)

Algal blooms occur because there are more nutrients available, so the producers can grow and reproduce more quickly. If there are not enough consumers to eat the excess algae, conditions can become so favorable for growth that algae cover the surface of the water. Algal blooms can sometimes upset the health of an ecosystem.

Why do all organisms require nitrogen? (p78)

All organisms require nitrogen to make amino acids, which in turn are used to build proteins.

What do Biogeochemical cycles connect?

Biogeochemical cycles connect BIOLOGY, GEOLOGICAL, and CHEMICAL aspects of the biosphere.

What role does denitrification play in the nitrogen cycle? (78-79)

Denitrification releases nitrogen into the atmosphere.

If a nutrient is in short supply in an ecosystem, how will it affect an organism? (p80)

If a nutrient is in short supply, it will limit an organism's growth.

What is the typical limiting factor in streams, lakes, and freshwater environments? (p80)

In streams, lakes, and freshwater environments, phosphorus is typically the limiting nutrient.

In the ocean and other saltwater environments, what is often the limiting factor? (p80)

In the ocean and other saltwater environments, nitrogen is often the limiting nutrient.

Matter moves through an ecosystem in ____.

Matter moves through an ecosystem in BIOGEOCHEMICAL CYCLES.

What is the main reservoir of nitrogen in the biosphere? (p78)

Nitrogen gas (N2) makes up 78 percent of Earth's atmosphere.

Why is phosphorus essential to living things? (p79)

Phosphorus is essential to organisms because it helps forms important molecules like DNA and RNA.

In what process do plants use carbon dioxide? (p76-77)

Plants take in carbon dioxide and use the carbon to build carbohydrates during photosynthesis.

What is nitrogen fixation? (p78)

Process of converting nitrogen gas into ammonia.

What are the four elements that make up over 95 percent of the body in most organisms?

The four elements that make up over 95 percent of the body in most organisms are: 1. Oxygen 2. Carbon 3. Hydrogen 4. Nitrogen

What is the primary productivity of an ecosystem? (p80)

The primary productivity of an ecosystem is the rate at which organic matter is created by producers.

Water can enter the atmosphere by evaporating from the leaves of plants in the process of _____. (p75)

Transpiration

When an aquatic ecosystem receives a large input of a limiting nutrient, a. What is often the result, and b. What is this result called? (p80)

When an aquatic ecosystem receives a large input of a limiting nutrient a. the result is often an immediate increase in the amount of algae and other producers. b. the result is called an algal bloom.

When is a substance called a limiting nutrient? (p80)

When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, this substance is called a limiting nutrient.

What is denitrification? (p78)

When organisms die, decomposers return nitrogen to the soil as ammonia. The ammonia may be taken up again by producers. Other soil bacteria convert nitrates into nitrogen gas in a process called denitrification. This process releases nitrogen into the atmosphere once again.

Carbon Cycle: (p76) Give examples of BIOLOGICAL PROCESSES.

biological processes: > photosynthesis, > respiration, and > decomposition of plants and animals;

Carbon Cycle: (p76) Give examples of GEOCHEMICAL PROCESSES.

geochemical processes: > the release of carbon dioxide (CO2) gas to the atmosphere by volcanoes;

Carbon Cycle: (p76) Give examples of HUMAN ACTIVITY.

human activity: > mining, > burning of fossil fuels, and > cutting and burning of forests.

Carbon Cycle: (p76) Give examples of MIXED GEOCHEMICAL PROCESSES.

mixed biogeochemical processes: > the burial of carbon rich remains of organisms and > their conversion into coal and petroleum (fossil fuels) by the pressure of the overlying earth;

Which process(es) are involved in the water cycle? (p75) a. precipitation b.evaporation c.runoff d. fertilization

precipitation, evaporation, and runoff