Ecosystem Jars Lab - PDF

Lab 4 R A J A N I M E T S y S O C E Background In September1993, the first mission of Biosphere II, the largest self-sustaining closed ecological system ever made, came to a close . From its 3600 kiloliter, coral-filled ocean to its emerald rain forest, this unique laboratory was designed to study...

Lab 4 R A J A N I M E T S y S O C E Background In September1993, the first mission of Biosphere II, the largest self-sustaining closed ecological system ever made, came to a close . From its 3600 kiloliter, coral-filled ocean to its emerald rain forest, this unique laboratory was designed to study the fundamental ecological processes on Earth. Biosphere II demonstrated that there must be a dynamic balance between biotic and abiotic factors in the environment., and that two conditions must be met if an ecosystem is to remain stable: energy from sunlight must be converted into energy usable by organisms, and organic and inorganic nutrients must be recycled back into the environment. In this activity, you’ll test this idea by construction a sealed, minienvironment of your own. Procedure 1. Obtain a small clean glass jar with lid. A small jelly or pickle jar works best. Mark you name on the lid 2. Spread a 4-5 cm layer of sand on the bottom of the jar. 3. Slowly fill the jar three-fourths full with distilled water or tap water that has aged at least three days. Allow sand to settle on the bottom of the jar. 4. Carefully plant a live Elodea or other freshwater plant in the sand. Gently trim the top of the plant to fit the size of the jar, and make sure it is completely submerged. 5. Use a dropper to pick up several (7-10) Daphnia, and add these to the jar. Add a pinch of brewer’s yeast to the jar to serve as temporary food source for the Daphnia. 6. Close the jar and place your mini-environment in a sunny area or near some other light source. You’ve just constructed a selfsustaining, balanced ecosystem that can last from several months to a year. Name _______________________________Teacher _______________________MOD_____ A n a ly z e a n d C o n c l u d e 1. With the addition of live plants, nutrient-recycling bacteria were also introduced to your minienvironment. Bacteria, as well as yeast, serve as food for Daphnia. In your own words, describe why your min-environment is a balanced ecosystem. Include the words consumer, producer, and decomposer in your answer. ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ ___________________________________________________________________________ 2. A food chain is the specific sequence in which organisms obtain energy in a ecosystem. In the space below, diagram the food chain in your mini-environment. 3. Ecosystems will remain in equilibrium unless disturbed by external factors. Describe the ecological consequences of the following situations. A. A rare disease kills all the Daphnia in the mini-environment ______________________________________________________________________________ ______________________________________________________________________________ B. The mini-environment was placed in a dark part of the room. ______________________________________________________________________________ _____________________________________________________________________________ C. Elodea plants were thoroughly cleansed of all bacteria before being planted. ______________________________________________________________________________ ______________________________________________________________________________ 4. Describe how carbon and oxygen are recycled in your mini-environment. ______________________________________________________________________________ _____________________________________________________________________________ ______________________________________________________________________________ Micro-Communi es Lab Name___________________________________________ Examine your pond water and iden fy any organism you nd in it. Decide wether it is a consumer, producer or both. Decide if it is mo le or sessile. ti fi ti Producer or Consumer ti Name Motile or Sessile Ques ons: 1. Did you nd more producers or consumers in your jar? _______________________________________ 2. What things in your jar would be abio c factors? ____________________________________________ 3. What color were most of your producers? _________________________________________________ 4. Producers carry out photosynthesis. What gas do producers make that is needed by the micrcommunity? ________________________________ 5. Which tended to be more mo le (producers or consumers)? __________________________________ 6. Do you think you have a good balance between producers and consumers in your jar?______________ 7. Over the next few weeks do you think you will nd more, less, or the same amount of diversity in your jar? Why? ____________________________________________________________________________________ ____________________________________________________________________________________ fi ti ti fi ti ____________________________________________________________________________________