Unit Two Ecological Interactions Chapter 4 Matter and Energy in the Ecosystem

ROLES OF LIVING THINGS Consumers Producers Decomposers

Producers – Autotrophs Organisms that make their own food from inorganic molecules and energy from the sun auto = self troph = feed Photosynthesis – the chemical process that produces sugar from CO2 and energy from sunlight protists – phytoplankton plants – corn, rice, grass, wheat)

Consumers – Heterotrophs Organisms that must eat food for energy hetero = other troph = feed Herbivores – organisms that eat only plants (cows) Carnivores – organisms that eat only herbivores or other carnivores (wolves) Omnivores – organisms that eat both plants and animals (bears; humans)

Decomposers Wood ear Bacteria and fungi that consume the bodies of dead organisms and organic wastes Decomposers complete the cycle of matter in the ecosystem Ex: Fungi: wood ear, portabella Bacteria: E. coli, Salmonella Portobello E. coli Salmonella

Trophic Levels A layer of the feeding relationships in an ecosystem First level – producers Second level – herbivores Third level – first order carnivores Fourth level – second order carnivores Each level completely depends on the level below it

Ecosystem Structure Food Chain A series of organisms that transfer food between trophic levels of an ecosystem Always begins with producers Decomposers supply the nutrients that begin the cycle

Ecosystem Structure Food Web A network of food chains representing the feeding relationships among organisms in an ecosystem Changes in any organism affects the other populations

FACTORS THAT AFFECT THE ECOSYSTEM ABIOTIC BIOTIC WEATHER CLIMATE SOIL QUALITY AVAILABLILITY OF FRESH WATER POLLUTION CONTAMINATION PLANT LIFE BIODIVERSITY ANIMAL POPULATIONS HUMAN ACTIVITY

BIOTIC FACTOR: BIODIVERSITY The number of connections in a food web varies in every ecosystem (few species in the polar ice caps to many in the tropical rain forest) The older or more complex food webs are more stable and are more resistant to natural or man-made disasters

ABIOTIC FACTOR: BIO-MAGNIFICATION Ex: The pesticide DDT was used to control the mosquito population. Fish ate the sprayed mosquitos and their larvae which concentrated the DDT in the bodies of the fish. Eagles ate the contaminated fish. This caused the eagles to have defective shells and eggs broke decreasing the number of eagles being born. Pollution or chemical contamination that can be magnified in a food web The concentration of a pollutant in organisms increases as it moves up the trophic levels in a food chain.

Energy in the Ecosystem Ecological pyramids –show the relative energy in each trophic level Energy is NOT a renewable resource Energy, biomass or number pyramids decrease in value as you move up the trophic levels This means each trophic level gets less energy fro the food they consume than the previous level

Energy in the ecosystem BIOMASS – shows total amount of organic matter (energy) present in a trophic level Energy travels between one trophic level and the next in the form of food. 10% LAW – producers store 30% or LESS of sun’s energy, each trophic level after that only gets 10% of the available energy from the trophic level before.

Chemical Cycles 96% of your body is made up of four elements: carbon, oxygen, hydrogen, nitrogen Elements move the ecosystem in cycles Matter cycles repeatedly through the ecosystem The amount of matter that enters and leaves each cycle is small

Water Cycle Water Cycle – water moves between ocean, atmosphere and land Evaporation – water changes from liquid to a gas, moves into atmosphere Transpiration – evaporation of water from leaves of plants All of the fresh water we will ever have is already here

Carbon Cycle Producers (plants, bacteria and plankton) produce sugar using energy from the sun in a process called photosynthesis H2O + CO2 = C6H12O6 + O2 Consumers use the energy from food in a process called respiration C6H12O6 + O2 = H2O + CO2

Nitrogen Cycle Nitrogen is necessary to make amino acids – the building blocks of proteins Nitrogen is usually found as a gas in our atmosphere Bacteria help to convert nitrogen gas to ammonia and nitrates Legumes (peas, beans, peanuts) have specialized bacteria in their roots that covert nitrogen gas from the atmosphere into nitrates which can be used by plants to make amino acids