Lab 5: How Can a Nonliving Part of an Ecosystem Harm Living Things? PDF

Name _______________________________________Teacher _________________________MOD________ Lab 5: How Can a Nonliving Part of an Ecosystem Harm Living Things? OBJECTIVES In this exercise you will: • • Observe what happens when different salt solutions are added to planaria. Determine which solution...

Name _______________________________________Teacher _________________________MOD________ Lab 5: How Can a Nonliving Part of an Ecosystem Harm Living Things? OBJECTIVES In this exercise you will: • • Observe what happens when different salt solutions are added to planaria. Determine which solution is harmful to planaria. MATERIALS: • Planaria • Petri Dish • Stereoscope • 0.5%, 1%, and 5% salt solutions An ecosystem is a place with its living and nonliving things. The living parts are the biotic parts. The nonliving parts are the abiotic parts. The biotic parts of an ecosystem need the abiotic parts. Air and water are examples of abiotic parts that are needed by living things. The abiotic parts must be present in the right amounts. One abiotic part that living things need is mineral salts. Mineral salts are chemicals that contain several different elements. Some mineral salts, for example, are made of nitrogen, calcium, sulfur, and phosphorus. Living things get their mineral salts from soil or water. Often the soil or water contains too much or too little mineral salts for living things Keywords: Ecosystem __________________________________________________________________ Abiotic __________________________________________________________________ Biotic __________________________________________________________________ Ecology __________________________________________________________________ Procedure: 1. Place a planaria in one half of a petri dish. 2. Examine it under the stereoscope. Watch how it moves. 3. If you look carefully you will be able to observe its eyespots. Procedure Continued: 4. Make a drawing of your planaria in Table 1 and describe how it moves. 5. Add a squirt of 0.5% salt solution to the petri dish. 6. Use the stereoscope to look for the planaria again. Record your observations of appearance and movement in Table 1. 7. Using the same procedure, continue adding 1% and 5% solutions. Table 1: Effects of Salt Solutions on Planaria Observations No Salt 0.5% Solution 1% Solution 5% Solution Drawing Movement Questions: 1. Which salt solutions caused a shape change in the planaria? __________________________________ 2. Which solutions caused a change in the movement of the planaria? ____________________________ 3. Which solution did not change the shape and movement of planaria? __________________________ 4. Which solution is the strongest salt solution? _________________ 5. Which solution do you think was most harmful to the planaria? _________________ Explain your answer. _____________________________________________________ 6. Sometimes chemical are added to streams and ponds to kill underwater animals or plants. Not all animals die when chemicals are added to a stream. How could you explain this? ____________________________________________________________________________________ ____________________________________________________________________________________