17decomposerproducerconsumersA diagram called a food chain shows the flow of energy in an ecosystem. The energy flows from the sun producers consumers decomposers (once organisms are no longer living). A diagram called a food web shows how many food chains are connected.
18A tropism is a growth response by plants away from or towards stimuli. Organisms respond to external (outside) and internal (inside) stimuli.A response is an action or change in behavior that occurs as a result of a stimulus.A stimulus is a change in an organism’s surroundings that causes the organism to respond.A tropism is a growth response by plants away from or towards stimuli.
19The CyclesThe water cycle, the carbon and oxygen cycle, and the nitrogen cycle are all cycles where energy and matter interact within an ecosystem.
20The Water Cycle Precipitation CondensationWater vapor cools and changes from a gas to a liquid. The water droplets clump together around tiny dust particles in the air, forming clouds.TranspirationPlants give off water vapor through their leaves.PrecipitationWater droplets become so heavy they fall back to Earth as rain, sleet, snow, or hail.The Water CycleCollectionWater collects underground, in lakes, ponds, rivers, and oceans.EvaporationWater absorbs energy from the sun to change from a liquid to a gas and rise into the upper atmosphere.
21The Carbon – Oxygen Cycle Producers take in _carbon dioxide__ gas to use to make food in a process called photosynthesis.During photosynthesis, the producer releases oxygen into the air as a waste product during respiration.During respiration, consumers release carbon dioxide into the air as a waste product.Consumers take in the oxygen and eat the producers to make energy.The Carbon – Oxygen Cycle
23The nitrogen cycle is a representation of the various forms of N and how they relate to one another through many complex interactions. Nitrogen is the major component of earth's atmosphere. It enters the food chain by means of nitrogen-fixing bacteria and algae in the soil. This nitrogen which has been 'fixed' (combined with other elements) is now available for plantsto absorb in different nitrogen compounds. These types of bacteria form a symbiotic relationship with legumes--these types of plants are very useful because the nitrogen fixation enriches the soil and acts as a 'natural' fertilizer.
24The nitrogen-fixing bacteria form nitrates out of the atmospheric nitrogen which can be taken up and dissolved in soil water by the roots of plants. Then, the nitrates are incorporated by the plants to form proteins, which can then be spread through the food chain. When organisms excrete wastes, nitrogen is released into the environment. Also, whenever an organism dies, decomposers break down the corpse into nitrogen in the form of ammonia. This nitrogen can then be used again by nitrifying bacteria to fix nitrogen for the plants.
25BiomassBiomass is the total amount of living matter, and the remains of dead organisms in an area. The decay of biomass releases energy into an ecosystem and recycles the dead matter back into the environment.