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Chapter 3 Ecosystem Ecology. Ecosystem Ecology Examines Interactions Between the Living and Non-Living World. Ecosystem – a particular location on Earth distinguished by its particular mix of interacting biotic and abiotic components. Ecosystem Boundaries. - PowerPoint PPT Presentation
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Chapter 3Ecosystem Ecology
Ecosystem – a particular location on Earth distinguished by its particular mix of interacting biotic and abiotic components
Ecosystem Ecology Examines Interactions Between the Living and Non-Living World
Some ecosystems, such as a caves and lakes have very distinctive boundaries
However, in most ecosystems it is difficult to determine where one ecosystems stops and the next begins
Ecosystem Boundaries
Even though it is helpful to distinguish between two different ecosystems, ecosystems interact with other ecosystems
Ecosystem Processes
Energy Flows through Ecosystems
Producers (autotrophs) are able to use the sun’s energy to produce usable energy through the process called photosynthesis
Photosynthesis and Respiration
Cellular respiration is the process by which other organisms gain energy from eating the tissues of producers
Photosynthesis and Respiration
Consumers (heterotrophs) – obtain energy by consuming other organisms
Primary Consumers (herbivores) – consume producers
Secondary Consumers (carnivores) – obtain their energy by eating primary consumers
Tertiary Consumers (carnivores) – eat secondary consumers
Trophic Levels, Food Chains, and Food Webs
Consumers (heterotrophs)
• scavengers: feed on dead organisms
Consumers (heterotrophs)
• detritivores: feed on detritus (partially decomposed organic matter, such as leaf litter & animal dung) and breakdown this organic material into smaller particles
Consumers (heterotrophs)
• decomposers: consumers that complete the “circle of life” by digesting organic materials into smaller molecules
What is the difference between a food chain and a food web?
Food Chains
Food chain – the sequence of consumption from producers through tertiary consumers
Food web – a more realistic type of food chain that takes into account the complexity of nature
Food Web
Gross primary productivity (GPP) – the total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time
Net primary productivity (NPP) – the energy captured (GPP) minus the energy respired by producers◦NPP = GPP – energy used by producers◦Measured in kg C/m2/year
Ecosystem Productivity
Where in the world is NPP the highest?
Net Primary Productivity
Net Primary Productivity
Why do food chains rarely have more than 4 or 5 trophic levels?
What do you think?
Food Chains
Which are more numerous in an ecosystem: producers or consumers?
Producers are always more numerous than consumers, why?
Energy LossOf the energy that an organism consumes, only a
small fraction (ecological efficiency of about 10%) is transferred to the next trophic level
Where does that energy go?
• Most of the energy is lost as heat