Ecosystems

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

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

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?

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

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

Heterotrophs

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

Trophic Levels (feeding levels) 3 2 1

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

Food webs

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

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

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

Three hundred trout are needed to support one man for a year 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?

Pyramid of Numbers Shows the numbers of individual organisms at each trophic level in an ecosystem. tertiary consumers secondary primary producers 5 5000 500,000 5,000,000 A vast number of producers are required to support even a few top level consumers.

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