Producers
Ecosystems
• An ecosystem includes biotic and abiotic factors.
13.1 Producers and Consumers
• Ecology is the study of the interactions between living things and their environment.
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Producers
• Producers are organisms that use light energy from the Sun or energy from chemical reactions to make their own food.
• Producers use carbon dioxide and water to make sugars, which they use as food.
13.1 Producers and Consumers
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Plants
• Most green plants are producers.
• Plants use light energy, water, and carbon dioxide and make simple sugars. Photosynthesis.
• These sugars are a source of energy and carbon.
13.1 Producers and Consumers
Protists and Bacteria
• Some protists and bacteria are producers.
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Chemosynthesis• Some bacteria make food using energy from chemical
reactions in a process called chemosynthesis.
• Some chemosynthetic bacteria live deep in the ocean where sunlight never reaches. (p. 552)
13.1 Producers and Consumers
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13.1 Producers and Consumers
Consumers
Consumers• Consumers are organisms that cannot make their
own food.
– All animals are consumers because they eat other organisms or their wastes.
– Some consumers eat producers, and some eat other consumers.
– Some consumers, such as protozoans, are single-celled.
13.1 Producers and Consumers
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Types of Consumers
• Herbivores are animals that eat only plants.
• Carnivores are animals that only eat other animals.
• Omnivores are animals that eat other animals and plants.
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Types of Consumers (cont.)
• Scavengers are organisms that eat dead animals.
• Decomposers break down dead organisms, and animal droppings, and other wastes produced by living things. (page 556)
13.1 Producers and Consumers
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Energy in Ecosystems
Energy Through the Ecosystems
• Organisms do not create or destroy energy; they change it from one form to another.
• Energy moves one way through an ecosystem—from producers to consumers and decomposers.
13.2 Energy in Ecosystems
• Energy passes through ecosystems as food.
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Food Chains• A food chain is an illustration of how energy moves
though an ecosystem.
13.2 Energy in Ecosystems
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Food Webs• An ecosystem contains more than one type of producer,
and most organisms eat more than one type of food.
• A food web is a more complicated model of the flow of energy in an ecosystem.
13.2 Energy in Ecosystems
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Food Webs (page 560)
13.2 Energy in Ecosystems
Energy Pyramid
Energy Pyramids• An energy pyramid is a diagram that shows how much
energy is available to each type of consumer.
– The bottom layer has the most available energy and contains the producers.
– The middle layers contain primary consumers and secondary consumers.
– The small top layer has the least available energy and contains tertiary consumers.
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Energy Pyramids (cont.)
Temperate Deciduous Forest
13.2 Energy in Ecosystems
Energy Pyramids (cont.)
Desert
13.2 Energy in Ecosystems
Energy Pyramids (cont.)
Tropical Rainforest
13.2 Energy in Ecosystems
Releasing Thermal Energy• All organisms release some energy in food as thermal
energy.
• This is why less energy is available with each step up an energy pyramid. (page 564)
13.2 Energy in Ecosystems
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Water and Nitrogen Cycles
Cycles of Matter• The amount of matter—anything that has mass and takes
up space—on Earth never changes.
• Elements that make up matter cycle among living things and between abiotic and biotic environments.
• Water, nitrogen, phosphorus and carbon cycles.
13.3 Matter in Ecosystems
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Water Cycle• Movement of water from Earth’s surface to the
atmosphere and back.
• Three main steps:
– Evaporation: Change from liquid water to water vapor
– Condensation: Change from water vapor to liquid water. Makes clouds.
– Precipitation: Water falls back to earth as rain, snow sleet or hail
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Water Cycle
12.1 Abiotic and Biotic Factors
Nitrogen Cycle
• Nitrifying bacteria change atmospheric nitrogen into forms of nitrogen that plants can take up through their roots.
• Consumers eat the plants and get the fixed nitrogen.
• When consumers die, fixed nitrogen is returned to the soil then bacteria releases free nitrogen back to the air. (P. 568)
• The nitrogen cycle describes how nitrogen moves from the atmosphere to the soil, to living organisms, and then back to the atmosphere.
13.3 Matter in Ecosystems
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Phosphorus and Carbon Cycles
Phosphorus Cycle• The phosphorus cycle describes how
phosphorus moves from soil to producers and consumers, and back to soil.
13.3 Matter in Ecosystems
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The Carbon Cycle• The carbon cycle describes how carbon moves
between the living and nonliving environments.
• Carbon is the key element in sugars, proteins, starches, and many other compounds that make up living things. (page 570)
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The Carbon Cycle (cont.)13.3 Matter in Ecosystems
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