Ecosystems An ecosystem includes all of the organisms

Ecosystems

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

• A community is a group of different species that live together in one area. Community 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 sunlight moisture

What is the primary source of energy for an ecosystem?

Sun’s Energy l l l 7 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

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

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

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

What is photosynthesis? copyright cmassengale 12

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

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

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

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

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 Web copyright cmassengale 27

copyright cmassengale 28

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

Food webs

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

Trophic Level Producer, primary consumer, secondary consumer, tertiary consumer Producer Grass 1 st Mouse 2 nd Primary consumer Grasshopper 2 nd Primary consumer Frog 3 rd Secondary consumer Owl 3 rd and 4 th Hawk 3 rd Secondary and tertiary consumer 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 75 g/m 2 150 g/m 2 secondary consumers primary consumers producers 675 g/m 2 2000 g/m 2

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

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

PYRAMID OF NUMBERS 39

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

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

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

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 has the the most energy? most organisms? least energy?