Name:                                                                Period:

Energy Transfer Lab                                            

How does energy flow through ecosystems?  Energy flows through ecosystems in one direction from photosynthetic organisms to herbivores to carnivores and decomposers. The total energy found in organisms from one trophic level in a food chain is available to organisms in the next trophic level is limited as only a portion of energy consumed is stored as organic matter; the rest is utilized in metabolic processes or transformed into heat.

Directions:

You will be simulating the transfer of energy through levels of a model ecosystem in order to determine the efficiency of energy transfer.  Your group will participate as either the Red or Black group.

 

  1. Obtain a set of four cups labeled “Red Group” or “Black Group”; you should have one of each of the following cups for Red Group: 1, 2, 3, 4 or the following for Black Group: 1, 2, 3.

  1. Pour 1 liters (1000 mL) of water into  your first container; this is the starting volume for the first container.

  1. You will be transferring water from the “Water Source” to Cup 1, Cup 2, etc. Water will be lost during this process.  You will need to determine the efficiency of water transfer during this process, i.e. how much water each cup starts with and ends with.  You must be able to calculate how much water was moved out of the first container to the final container (container 4 for red group or container 3 for black group) in a one minute time period. Determine how your group will calculate this and write out a plan below.

  1. Conduct three trials of water transfers; each trial will last 60 seconds.  Prizes for the most efficiency group (you may not plug holes in cups)

  1. Record volumes and efficiency of transfer in Table 1.

Table 1. Efficiency of Water Transfer

Trial

Volume from 1st Container (mL)

Volume from Final Container (mL)

Efficiency of Water Transfer (mL)

1

1000mL

2

1000mL

3

1000mL

Average Efficiency of Water Transfer:

Analysis:

  1. What conclusions can you draw about the efficiency of water transfer?  Use data to support your answer.

  1. Add, not literally but figuratively, the following labels to your cups: Cup 1=Grass, Cup 2=Field Mouse, Cup 3=Snake, Cup 4=Hawk.  How does this represent the transfer of energy in these simplified ecosystems.

  1. What do these cups, overall, represent (beyond the organisms).

  1. What comparisons can be drawn between water lost in the activity and energy lost in ecosystems?

  1. Define Trophic-Level:

  1. Approximately how much energy is lost each step up the food chain?

  1. Explain the flow of energy in a food chain.

Vocabulary Review

  1. A(n) _____________________________ is a functional unit consisting of all the living organisms (plants, animals, microbes) and non-living materials in a given area.

  1. The transfer of food energy from plants to one or more animals in a linear sequence is known as a _______________  _______________.

  1. An organism that uses light energy or energy stored in chemical compounds to make energy-rich compounds is known as a(n) ________________________________.

  1. An organism that cannot make its own food and feeds on other organisms is a(n)                 _______________________.

  1. _______________________ uses sunlight to make food.

  1. _______________________ obtains food from photosynthetic organisms.

  1. _______________________ eats meat in the form of other animals.

  1. _______________________ breaks down and releases nutrients from dead organisms.