Ecology Notes 2

The sun is the ultimate source of energy  _________ (producers) trap the sun’s energy to carry out _____________ – the changing of energy to sugar  Other autotrophs use chemosynthesis to make organic molecules from chemicals chemosynthesis  __________ (consumers) feed upon producers and each other and transfer the stored energy Autotrophs Heterotrophs photosynthesis

What is a food chain?  This is the transfer of materials and potential energy from organism to organism grassmousesnakeowl decomposer (bacteria) **a food chain always begins with a producer!!

What is a food web?  Interacting food chains

What is a trophic level?  A feeding step in the passage of energy and materials 1.4 th level 2.3 rd level 3.2 nd level 4.1 st level 5.Decomposer Video clip Video clip producers 1 st order consumers 2 nd order consumers 3 rd order consumers

1. 1 st trophic level  – trap sun’s energy autotrophs 1 st order consumers 2 nd order consumers 3 rd order consumers

2. 2 nd trophic level  feed on producers feed on producers first order consumers producers 1 st order consumers 2 nd order consumers 3 rd order consumers

3 rd trophic level  – feed on 1 st order consumers Second order consumer producers 1 st order consumers 2 nd order consumers 3 rd order consumers

4. 4 th trophic level  – feed on 2 nd order consumers third order consumer producers 1 st order consumers 2 nd order consumers 3 rd order consumers

5. Decomposers (aka saprophyte) & Scavengers  Found at all trophic levels!  Ex- earthworms, mites, crabs, vultures, fungi, bacteria Break down dead organism s and waste Eat dead organism s and waste

Pyramid of Numbers Shows the relative number of individual organisms at each trophic level. Biomass Pyramid Represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid. Energy Pyramid Shows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat. Ecological Pyramids

Nutrient Cycles  Nutrients, like water, carbon, phosphorus, and nitrogen are cycled between organisms and the environment. Video clipVideo clip: water cycle on Internet Video clip

Condensation Seepage Runoff Precipitation Transpiration Evaporation Root Uptake The Water Cycle

CO 2 in Atmosphere CO 2 in Ocean The Carbon Cycle: carbon is found in all living things 6CO 2 + 6H 2 O  6CO 2 + C 6 H 12 O 6 Video clip

N 2 in Atmosphere NH 3 NO 3 - and NO 2 - The Nitrogen Cycle: nitrogen is used to make amino acids & proteins. It must be “fixed” by bacteria before we can use it. Video clip

The Phosphorus Cycle  Important in making DNA & RNA  Not very common in the biosphere  Can be found in small quantities in water and on land, but not in the air  Phosphorus is often a limiting nutrient, meaning that the growth of organisms is limited by how much phosphorus is available. (That’s why we use fertilizers).  If a pond suddenly receives an excess of the limiting reagent (pollution, runoff…), it can cause algal blooms (bad for environment).