Unit 2 Ecosystems and How They Change

Everything in an ecosystem interacts by 2 main processes: Everything in an ecosystem interacts by 2 main processes: and

The SUN is the original energy source for most organisms. The SUN is the original energy source for most organisms.

PRODUCE CARBOHYDRATES (SUGARS) BREAK DOWN CARBOHYDRATES TO RELEASE ENERGY and SUN AUTOTROPHS PRODUCE CARBOHYDRATES (SUGARS) AUTOTROPHS AND HETEROTROPHS

Photosynthesis process that converts solar energy into chemical energy stored in the bonds of organic compounds, usually carbohydrates process that converts solar energy into chemical energy stored in the bonds of organic compounds, usually carbohydrates 6CO 2 + 6H 2 O + light energy  C 6 H 12 O 6 + 6O 2

Respiration The release of chemical energy from food for cellular use The release of chemical energy from food for cellular use C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O + energy

AUTOTROPHS AUTOTROPHS Organisms that use energy to make their own food (producers) Organisms that use energy to make their own food (producers) HETEROTROPHS HETEROTROPHS Organisms that cannot make their own food (consumers) Organisms that cannot make their own food (consumers) Feed on autotrophs or on other heterotrophs that feed on autotrophs Feed on autotrophs or on other heterotrophs that feed on autotrophs All life depends on AUTOTROPHS. All life depends on AUTOTROPHS.

Who Eats What in an Ecosystem NameEnergy SourceExamples ProducerMakes its own foodgrasses, ferns, trees, some bacteria ConsumerGets energy by eating other organisms HerbivoreEats only producerscows, sheep, deer, grasshoppers CarnivoreEats only other consumers lions, hawks, wolves, pike OmnivoreEats both producers and consumers bears, pigs, humans Decomposer Breaks down dead organisms, returning nutrients to the soil or water fungi, bacteria

Specific sequence in which organisms obtain energy in an ecosystem Specific sequence in which organisms obtain energy in an ecosystem Usually only 4 or 5 levels Only a portion of the energy available to organisms at each level of the food chain is stored Only the stored energy is available to organisms at the next trophic level

The interrelated food chains in an ecosystem The interrelated food chains in an ecosystem

Trophic level Trophic level each step in the transfer of energy through an ecosystem each step in the transfer of energy through an ecosystem Describes how far an organism is removed from plants in a food chain Describes how far an organism is removed from plants in a food chain An organism cannot always be assigned to one trophic level An organism cannot always be assigned to one trophic level

Ecosystems seldom have more than 4 or 5 trophic levels Ecosystems seldom have more than 4 or 5 trophic levels Not enough food or energy to feed another level Not enough food or energy to feed another level Not all the food available at one level is actually eaten by animals at the next level Not all the food available at one level is actually eaten by animals at the next level Most of the energy is used in respiration, to repair body tissues, and for locomotion, circulation, and feeding Most of the energy is used in respiration, to repair body tissues, and for locomotion, circulation, and feeding

5-C MEASURING ENERGY FLOW: PRODUCTIVITY Primary productivity: the rate at which plants make more plant material by photosynthesis Primary productivity: the rate at which plants make more plant material by photosynthesis Net primary production: energy available to other organisms Net primary production: energy available to other organisms The world’s food supply The world’s food supply About half is used by plants for respiration About half is used by plants for respiration Limits the number of organisms that can survive on earth Limits the number of organisms that can survive on earth

Numbers Pyramid compares the number of individuals at each trophic level compares the number of individuals at each trophic level

Biomass Pyramid  compares the amount of biomass (total dry weight of the organisms in an ecosystem)  compares the amount of biomass (total dry weight of the organisms in an ecosystem)

Energy Pyramid  compares the total amount of energy in each trophic level  compares the total amount of energy in each trophic level