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Published bySamson Alexander Modified over 8 years ago
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Ecology is the study of how organisms interact with each other and their environment. Biotic Factors = living Abiotic Factors = nonliving
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Biosphere = Earth Biome = One type of environment seen in different parts of the world Ecosystem = All biotic and abiotic factors in a location
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Community = All organisms in a location Population = A group of one TYPE of organism (species) Individual = A single organism
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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
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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.
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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
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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.
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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…
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Only 10% of energy is passed on from one energy level to the next!!!
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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
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Note that it takes 10x’s the organis ms to support a higher consum er.
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Biomass pyramids show the total mass of organisms needed to sustain consumers.
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The pyramid of numbers displays the total number of organisms needed to support consumers.
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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.
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Hydrolic Cycle (Water Cycle) Carbon Cycle Nitrogen Cycle Phosphorus Cycle
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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.
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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.
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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.
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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).
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