1. Cycles of Matter
Ecology Unit II

2. Matter is Recycled in an Ecosystem, Energy is not
What is Matter?
Matter is made up of Atoms. Combinations of atoms are called molecules.
Three important cycles include:
The Water (Hydrologic) cycle
The Carbon & Oxygen Cycle
The Nitrogen Cycle

3. The Hydrologic cycle VIP of the water Cycle: The Sun.
The amount of solar energy causes water to cycle between its solid, liquid & gas phases.
Water moves from biotic to abiotic factors in ecosystems.

4. The Carbon & Oxygen Cycles
VIP of the Carbon/Oxygen Cycle: Producers & Consumers
When producers photosynthesize, they transform carbon dioxide gas and water into sugar, releasing oxygen as a by-product.
When consumers (and producers) use respiration to break down food they use oxygen and release carbon dioxide

5. light chemical mechanical + heat.
Photosynthesis
6CO2+6H2O +light energy--> C6H12O6+6O2
When a plant is eaten by a consumer, it serves as a form of chemical energy.
The consumers convert this chemical energy to mechanical energy and heat energy.
Energy Flow:
light chemical mechanical + heat.
sugar

6. Nitrogen Cycle VIP of the Nitrogen Cycle: Bacteria
Although nitrogen composes 78% of our air, we cannot use it in this form. Bacteria in soil must chemically change it to a “fixed” form. Then it can be used by plants and animals as a building block of our proteins.
When organisms die, nitrogen is recycled, or released back into the air.

7. Decomposers are part of the Nitrogen cycle
Break down dead organisms and animal waste
Examples: bacteria, maggots, fungi, worms
Complete the cycle of matter by returning nutrients including nitrogen to the soil
Decomposers are important parts of the food web that are not always represented well in textbook diagrams. Check to see how your textbook incorporates decomposers.

8. Plant Tropisms Plants respond to changes in their environment
A turning response is called a “tropism”
Phototropism = turning toward the light