Ecology Lesson 4 (Cycling of Matter)

biogeochemical cycles (bio = life; geo = earth)

the movement of important elements/molecules from the environment into an organism and back into the environment.

water cycle

moving water from Earth’s surface into the atmosphere and back.

water cycle processes

evaporation

condensation

precipitation

evaporation

water changing from liquid to gas (water vapor)

condensation

gas changing into a liquid when cooled

precipitation

large amounts of condensed water vapor that fall to earth (snow, rain, sleet)

carbon/oxygen cycle

the movement of carbon and oxygen from the non-living environment into living things and back.

parts of the carbon/oxygen cycle

photosynthesis

cellular respiration

(death &) decomposition

combustion

PCDC

photosynthesis

process by which carbon cycles INTO living things (plants) FROM the environment.

How energy enters ecosystem through photosynthesis

sunlight is used to convert (change) carbon dioxide into glucose (sugar).

Plants, algae and some bacteria use carbon dioxide to…

make carbohydrates (specifically glucose)

Most animals get the carbon they need from…

eating plants.

cellular respiration

organic molecules are broken down to release their energy.

Where cellular respiration occurs

in animal and plant cells

What carbon does in cellular respiration

Carbon cycles FROM living things INTO the environment. This is the opposite of what it does in photosynthesis.

decomposition

breakdown of organic materials into carbon dioxide and water.

Role of fungi and bacteria in carbon cycle

help return carbon to the environment as they decompose organic matter.

combustion

process of burning of a substance (fuel).

When living things (or once living things) are burned, they…

release carbon into the atmosphere. (burning of coal, oil, natural gas).

Nitrogen Cycle

the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems

Nitrogen

element found in proteins and is essential to the survival of both plants and animals.

How much of Earth’s atmosphere is made up of nitrogen?

78%

unstable though

How we get usable nitrogen

nitrogen-fixation

nitrogen-fixation (with arrows)

plants absorb nitrogen—>animals consume plant—>nitrogen cycled back through animal waste

Detailed definition of nitrogen-fixation

The process by which plants absorb nitrogen from the soil and change it into proteins.

Animals then consume the plant (or the animal that ate the plant) and use the nitrogen in that to build proteins.

Nitrogen is cycled back into the ecosystem through animal waste (urine and feces) and through decomposition.

denitrification

Process in which bacteria in the soil convert fixed nitrogen into nitrogen gas which then returns to the atmosphere.

Nitrogen is a factor that limits the growth of producers. Why?

The supply of nitrogen in the food web is dependent on the amound that can be fixed.

That’s why farmers use fertilizers that contain nitrogen. Its presence helps the producers grow.

carbon cycle steps

• Carbon enters the atmosphere as CO2 through animals breathing out, burning and decomposers doing their job.

• CO2 is absorbed by autotrophs such as green plants. Photosynthesis occurs and glucose and oxygen are made.

• Animals breathe in oxygen and consume plants, thereby, incorporating carbon into their system.

• Animals and plants breathe out CO2. When animals die, their bodies decompose and carbon is released and reabsorbed back into the atmosphere.

nitrogen cycle

The series of processes by which nitrogen and its compounds are taken from the environment and living organisms, including nitrogen fixation, nitrification, and denitrification.

processes in the nitrogen cycle

nitrogen fixation, nitrification, and denitrification.

nitrogen-fixation definition

The process by which nitrogen gas is converted into ammonia or related compounds in soil and water, making it available for uptake by plants.

ammonification

The process by which organic nitrogen from dead organisms and waste is converted into ammonia by decomposer organisms, making it available for nitrification.

denitrification

The process by which nitrates and nitrites are converted back into nitrogen gas by denitrifying bacteria, returning nitrogen to the atmosphere.

The supply of nitrogen in the food web is dependent on the amount that can be fixed; THEREFORE,

nitrogen is a factor that limits the growth of producers.

Nitrogen-fixation is essential for ecosystem health and productivity.

nitrogen cycle (more detailed with arrows)

N2 —> NH4 —> NO2 —> NO3

nitrogen gas —> ammonium —> nitrite —> nitrate—> assimilation (by plants) —> ammonification (by decomposers) —> denitrification (by bacteria)

What organism plays a major role in nitrogen cycle?

bacteria

what occurs during nitrification

ammonium is converted to nitrate in a two step process (nitrite to nitrate)

What occurs during assimilation?

the uptake of nitrate or ammonium by plants to produce organic nitrogen compounds.

Role of decomposers in nitrogen cycle

nitrogen is returned to the soil, environment, the ecosystem