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The Living World: Ecosystems
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Supports photosynthesis Contributes to the greenhouse effect
The Sun: Lights the Earth Warms the Earth Supports photosynthesis Generates wind Contributes to the greenhouse effect Solar radiation Energy in = Energy out Reflected by atmosphere (34%) UV radiation Radiated by atmosphere as heat (66%) Lower stratosphere (ozone layer) Visible light Greenhouse effect Absorbed by ozone Troposphere Heat Absorbed by the earth Heat radiated by the earth Earth
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Components of an ecosystem
Abiotic factors Water Air Nutrients Solar energy Biotic factors Plants Animals Microbes
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Components of an Ecosystem
Producers Autotrophs – “self-feeding” Plants/phytoplakton Photosynthesize for energy Consumers Heterotrophs Carnivores, herbivores, omnivores Feed on other organisms for energy Primary, secondary and tertiary consumers Decomposers Mostly bacteria and fungi Feed on detritus Detritivores/detritus feeders – carpenter ants, termites, etc.
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Components of an Ecosystem
Heat Abiotic chemicals (carbon dioxide, oxygen, nitrogen, minerals) Solar energy Decomposers (bacteria, fungus) Producers (plants) Consumers (plants, animals)
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Components of an Ecosystem
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Trophic Levels When a food chain is analyzed, organisms are placed in levels called trophic levels
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(decomposers and detritus feeders)
First Trophic Level Second Trophic Level Third Trophic Level Fourth Trophic Level Producers (plants) Primary consumers (herbivores) Secondary consumers (carnivores) Tertiary consumers (top carnivores) Heat Heat Heat Heat Solar energy Heat Heat Heat Heat Heat Detritivores (decomposers and detritus feeders)
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Energy Flow in Ecosystems
The energy transfer between levels is very inefficient. Only 10% of energy is transferred to the next level.
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Flow in Ecosystems Pyramids are various different shapes based on what they are showing Pyramids can show Energy Biomass Numbers
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Primary Productivity The rate which producers convert energy from the sun into usable chemical energy (glucose) Expressed in the terms Gross and Net Primary Productivity Gross is the total amount of energy made by the producer through photosynthesis Net is what is left after producer goes through cellular respiration Energy is used for growth and reproduction Net = Gross - Respiration
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Primary Productivity Sun Photosynthesis
Energy lost & unavailable to consumers Respiration Gross primary production Net primary production (energy available to consumers) Growth and reproduction
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Terrestrial Ecosystems Average net primary productivity (kcal/m2/yr)
Swamps and marshes Tropical rain forest Temperate forest Northern coniferous forest (taiga) Savanna Agricultural land Woodland and shrubland Temperate grassland Tundra (arctic and alpine) Desert scrub Extreme desert Aquatic Ecosystems Estuaries Lakes and streams Continental shelf Open ocean 800 1,600 2,400 3,200 4,000 4,800 5,600 6,400 7,200 8,000 8,800 9,600 Average net primary productivity (kcal/m2/yr)
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