 Ecology is the study of how organisms interact with each other and their environment.  Biotic Factors = living  Abiotic Factors = nonliving

 Biosphere = Earth  Biome = One type of environment seen in different parts of the world  Ecosystem = All biotic and abiotic factors in a location

 Community = All organisms in a location  Population = A group of one TYPE of organism (species)  Individual = A single organism

 PRODUCERS › Also called autotrophs › Make their own food  Photosynthesis = uses sunlight  Chemosynthesis = uses other means to make food  CONSUMERS › Also called heterotrophs › CANNOT make own food  Carnivores = meat eater  Omnivores = eats meat and plants  Herbivores = only eats plants  Decomposers = breaks down particles  Detritivores = eats dead matter

 Food chains show the flow of energy as organisms consume each other.  Food chains start with sun reaching a PRODUCER.  When a CONSUMER eats either a producer or a lower level consumer, an arrow is drawn pointing to the consumer.

 Each organism represents a trophic level.  For example, how many trophic levels are there in the following food chains? › Algae  Fish  Bear › Grass  Insect  Rodent  Owl  Decomposer

 Food webs include all of the food chains in an ecosystem and are more complicated.  Food chains in a food web may overlap with some consumers eating multiple organisms.

 The arrows in a food chain always go in ONE direction- toward the consumer!  More specifically, food chains show the flow of ENERGY from the sun to a producer to one or more consumers.  Since organisms need to use energy to grow, reproduce, etc., most of that energy is used or released as heat. So…

 Only 10% of energy is passed on from one energy level to the next!!!

 Sometimes energy flows can be displayed with an energy pyramid.  Producers are on the bottom with consumers on top because producers must support the rest of the food chain. › Primary consumers › Secondary consumers › Tertiary consumers

 Note that it takes 10x’s the organis ms to support a higher consum er.

 Biomass pyramids show the total mass of organisms needed to sustain consumers.

 The pyramid of numbers displays the total number of organisms needed to support consumers.

 Recall that ENERGY FLOWS in ONE direction. Once it is used, it is gone for good.  Sometimes nutrients and other materials go through CYCLES, which means they are RECYCLED back into the environment.

 Hydrolic Cycle (Water Cycle)  Carbon Cycle  Nitrogen Cycle  Phosphorus Cycle

 Water from the oceans, rivers, lakes, etc. evaporates into the air as it is warmed.  Clouds release precipitation (rain, snow, sleet, or hail) onto Earth.  Producers absorb some water. Rest either evaporates, enters soil as ground water, or runs-off into rivers, lakes, etc. until it reaches the ocean.

 Organisms exhale carbon dioxide (CO 2 ) into the air. Pollution containing carbon (e.g. oil, gas) is also released into the air.  Photosynthetic producers used CO 2 to make glucose. Producers can obtain carbon from the soil as well.  Consumers eat producers and other consumers, thereby consuming carbon. When organisms die, decomposers break down the carbon and release it into the soil.

 Organisms need nitrogen, but the form of nitrogen in the air (N 2 ) is not useable. It must be converted to nitrate (NO 3 - ) by one of two ways: › Struck by lightening › Changed by certain “nitrogen-fixing” bacteria  Nitrate enters the soil, where producers take it in through their roots.

 Nitrate (NO 3 - ) is passed to consumers as they eat producers and other consumers.  When organisms die, other bacteria called “denitrifying” bacteria convert nitrate (NO 3 - ) back to nitrogen gas (N 2 ).  Other forms of nitrogen are also put into the cycle through volcanic eruptions and human actions (e.g. use of fertilizer in agriculture).