Ecosystems

Organism Population Community Ecosystem An ecosystem includes all of the organisms as well as the nonliving things in a given area.

Organism Population Community A community is a group of different species that live together in one area.

An ecosystem includes both biotic and abiotic factors.  Biotic factors are living things.  plants  animals  fungi  bacteria plants

 Abiotic factors are nonliving things. –moisture –temperature –wind –sunlight –soil moisture sunlight

What is the primary source of energy for an ecosystem?

7 Sun’s Energy Most all living things need sunlight to survive. Directly or indirectly 0.023% used in photosynthesis

Producers  Makes food by changing light energy of the sun into chemical energy, or food  Also called Autotrophs  Ex. Plants, algae, some bacteria

9 Producers Sunlight is the main source of energy for most life on earth.Sunlight is the main source of energy for most life on earth. Producers contain chlorophyll & can use energy directly from the sunProducers contain chlorophyll & can use energy directly from the sun copyright cmassengale

10 Photoautotroph Producer That Captures Energy from the sun by: –Photosynthesis Adds Oxygen to the atmosphereAdds Oxygen to the atmosphere Removes Carbon Dioxide from the AtmosphereRemoves Carbon Dioxide from the Atmosphere Algae copyright cmassengale

11 On LandOn Land –Plants In The SeaIn The Sea –Algae Tidal Flats & Salt MarshesTidal Flats & Salt Marshes –Cyanobacteria Habitat of Photoautotrophs copyright cmassengale

What is photosynthesis? copyright cmassengale12

Consumers  Organisms that do not make their own food  Also known as HETEROTROPHS  Ex. Rabbits, Deer, Mushrooms

Heterotrophs

 Consumers  A. Herbivores – eat ONLY plants  Ex. – Cows, Elephants, Giraffes

Heterotrophs  Consumers  B. Omnivores – eat BOTH plants and animals  Ex. – Bears and Humans

Heterotrophs  Consumers  C. Carnivores – eat ONLY other animals  Ex. – Lions, Tigers, Hawks

Heterotrophs  Consumers  D. Scavengers/Detritivores – feed on the tissue of dead organisms (both plants and animals)  Ex. – Vultures, Crows, and Shrimp

Heterotrophs  Consumers  E. Decomposers – absorb any dead material and break it down into simple nutrients or fertilizers  Ex. – Bacteria and Mushrooms

Food Chain

Food Chains  The energy flow from one trophic level to the other is know as a food chain  Producers are at the first TROPHIC LEVEL  Primary Consumers are the SECOND TROPHIC LEVEL  Secondary consumers are at the THIRD TROPHIC LEVEL

22 Feeding Relationships Energy flows through an ecosystem in one direction from producers to various levels of consumers copyright cmassengale

23 Food Chain Producer ( trapped sunlight & stored food) 1 st order Consumer 2 nd Order Consumer 3 rd Order consumer 4 th Order Consumer copyright cmassengale

24 Name the Producer, Consumers & Decomposers in this food chain: copyright cmassengale

Trophic Levels (feeding levels)

Food Web  Most organisms eat more than JUST one organism  When more organisms are involved it is know as a FOOD WEB  Food webs are more complex and involve lots of organisms

27 Food Web copyright cmassengale

28copyright cmassengale

29 Trophic Levels Each Level In A Food Chain or Food Web is a Trophic Level. ProducersProducers –Always The First Trophic Level –How Energy Enters The System HerbivoresHerbivores –Second Trophic Level copyright cmassengale

Food webs

Trophic LevelProducer, primary consumer, secondary consumer, tertiary consumer? Grass Mouse Grasshopper Frog Owl Hawk

Trophic LevelProducer, primary consumer, secondary consumer, tertiary consumer Grass 1st Producer Mouse 2nd Primary consumer Grasshopper 2nd Primary consumer Frog 3rd Secondary consumer Owl 3 rd and 4th Secondary and tertiary consumer Hawk 3rd Secondary consumer

Transfer of Energy  When a lion eats a zebra, it does not get all of the energy from the zebra (much of it is lost as heat)  Only 10% of the energy from one trophic level is transferred to the next – this is called the 10% rule

Ecological Pyramid: Pyramid of Energy

Biomass pyramid Biomass is a measure of the total dry mass of organisms in a given area. tertiary consumers secondary consumers primary consumers producers 75 g/m2 150g/m2 675g/m2 2000g/m2 producers 2000g/m2

37 Pyramid of Biomass Grassland environment 10,000kg of grass Supports 1,000kg of grasshopper Supports 100kg of toads

38 PYRAMID OF NUMBERS The pyramid of numbers similar in shape to the pyramid of energy or biomass, but there are exceptions. No information about the biomass and energy relationships from one trophic level to the next.

39 PYRAMID OF NUMBERS

Pyramid of Numbers Shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers secondary consumers primary consumers producers ,000 5,000,000 producers A vast number of producers are required to support even a few top level consumers.

41 Human Impact on Ecosystem Ancestors survived by collecting plants and eating animals that they caught. Impact on the ecosystem was small. Two important demands on the ecosystem were plant and animals for food and wood for fuel.

42 Human Impact on Ecosystem Human populations increased, need for more energy (food) also increased. People started to practice agriculture by planting crops and raising animals. Cutting down trees and clearing decreased the number of producers, thus lowering the numbers in the lower trophic levels.

 Three hundred trout are needed to support one man for a year. The trout, in turn, must consume 90,000 frogs, that must consume 27 million grasshoppers that live off of 1,000 tons of grass. -- G. Tyler Miller, Jr., American Chemist (1971)

Ecological Pyramid Which level has the most energy? Which level has the most organisms? Which level has the least organisms? Which level has the least energy?