Energy Flow and Food Webs Ms. Petrauskas

The spheres Hydrosphere: all of the earths water (as a solid, liquid or gas) Lithosphere: the earths solid outer layer (rocks, earth etc.) Atmosphere: the layer of gases surrounding the earth Biosphere: the zone around the earth where life can exist ( part of the lithosphere, hydrosphere and atmosphere)

Source of all energy… Radiant energy- the energy radiated from the sun Composed of ultraviolet rays and visible light 70% absorbed by the hydrosphere and the lithosphere and converted to thermal energy Thermal energy warms the earth The rest goes back to space

Solar Radiation Distribution

Photosynthesis Light energy is used by some organisms and is converted to chemical energy (plants, some algae and some protists) Carbon dioxide + water sugar + oxygen Carbon, Oxygen, and Hydrogen are rearranged via light energy into sugar and oxygen Light Energy

Cellular Respiration The process by which sugar and oxygen are converted to carbon dioxide and water to provide energy for the cell (Ex. Human cells use sugar to make energy) Sugar +Oxygen carbon dioxide +water

Equilibrium A balance of photosynthesis and cellular respiration are part of a stable and healthy ecosystem

Trophic levels Autotroph –producer Primary consumer – herbivore Secondary consumer – usually carnivore or omnivore Tertiary consumer- usually carnivore/ omnivore/ detrivore Decomposer

A. Autotrophs (Producers) Organisms that photosynthesize ( produce their own food) Ex. Plants, algae and some bacteria

B. Heterotrophs (Consumers) Organisms that must consume (eat) other organisms to obtain energy and building materials 4 types of consumers depending on what they eat. (Herbivores, Carnivores, Omnivores, Scavenger/ Detrivores)

1. Herbivore Eat only plants Ex. Deer, giraffes, cows, pandas, humming birds, grasshoppers

2.Carnivores Eat only animals (including insects) Ex. Killer whales, praying mantis, lions, tigers, wolves, hawks

3.Omnivore Eat both plants and animals Ex. Bears, robins, raccoons, blue jays, fox, humans

4. Scavengers/Detrivores Feed on dead or decaying animal matter Ex. Crows, crayfish, vultures –Scavengers Ex. Worms, wood beetles

C. Decomposers Another trophic level Consume remaining dead or decaying material Break down organic matter to its nutrients Nutrients are returned to the soil Ex. Mould, yeast, mushrooms

Food chain A series of predator-prey relationships (predators eat prey) Each chain begins with the sun Producers are next as they use the sun’s energy to produce glucose Consumers eat the producers Decomposers return nutrients to the soil

Create your Own food chain Start with the sun producer  primary consumer secondary consumer tertiary consumer  end with the quanternary consumer or decomper Arrows point in the direction of energy flow. TRY IT!!!!!!

Food Webs A more accurate way to show feeding relationships within a community Consumers feed on many species, therefore reducing the vulnerability of any one prey species and reliability on one prey species Useful to see what happens when one species is removed from the web or added to the web (invasive species)

Ecological Pyramids Display relationships between trophic levels. As the pyramid narrows it shows that energy has been lost Can represent energy, biomass or numbers of organisms

Energy loss As one organism consumes another energy is transferred Some energy is lost as thermal energy Consider how much heat you lose compared to a plant! Only 10% of the energy consumed by one trophic level is passed onto the next trophic level

10% is transferred between trophic levels Carnivore (20J) Herbivore (200J) Plants(2000J of sun’s energy)

Create your own…..start with 1,000,000J of energy 100,oooJ 10,000J 1,000J 100 J

Analogy Cut a pie into 10 equal slices Only 1 piece is available to the next trophic level Cut that slice into 10 smaller slices Only 1 of those is available to the next trophic level

Biomass Pyramid: mass of all living organisms in an area Predator, parasites Insect herbivore Grass

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