Modeling Ecosystems Virtual Lab

Introduction: In this exercise, you will examine one assigned ecosystem’s characteristic plant and animal species. To begin, read the information in the “Field Guide” to learn more about the organization of your assigned ecosystem.

Directions

  1. To open the virtual lab go to 37-StuCommon, open Montgomery, open “Documents”, open “Lab Activities” and right click on the “Modeling Ecosystems Lab”
  1. Read through the information to the left side of the screen to complete the background information.
  1. You are now ready to begin the activity. Start by selecting your assigned ecosystem from the pull down menu at the top of the screen.
  1. Click and drag the various organisms to their correct locations within the different trophic levels of the pyramid. Once you have moved all of the organisms click the “Check” button. Any incorrectly placed organisms will go back to the right side of the screen, you must fix your mistakes and click “Check” again until all organisms are placed on the pyramid in their correct trophic level.

Data Collection

  1. List each of the organisms (by name) at each trophic level under the “Organisms Present:” area on Table 1.
  1. Clicking on the “Pyramid of Numbers” will show the number of organisms at each trophic level within this type of ecosystem. Fill in this information from the pyramid on Table I below under the “Numbers:” area.
  1. Clicking on the “Pyramid of Energy” will reveal how much energy is available at each trophic level. Fill in this information from the pyramid on Table 1 below under the “Energy:” area.

Calculating the E.C.E - Energy Conversion Efficiency

  1. You must take one last step in the investigation of this ecosystem. It is important to determine the amount of energy that is transferred from one trophic level to the next. This is called the “Energy Conversion Efficiency” (E.C.E.) This ratio is determined by choosing a trophic level and dividing the energy available by the energy available in the trophic level below it. Please do these calculations as directed below and input the data in Table I. Note: This will only work for trophic levels above the autotrophs (producers).

Example: First Order Heterotrophs / Producers multiplied by 100 = ECE for First Order Heterotrophs

  1. When you are completely finished analyzing your assigned ecosystem, add vocabulary to your Quizlet flashcards, then study for the vocabulary test!

Name: ______Date: ______Hr: ____

Modeling Ecosystem Virtual Lab –

Your assigned ecosystem is: ______

Background Information:

An ______consists of a community of living organisms ______with each other and the ______. The source of energy that fuels most ecosystems is the ______. Plants use the Sun’s energy to produce food in a process called ______.

Organisms that use energy from the Sun or energy stored in ______compounds to produce their own nutrients are called autotrophs. They are also called ______because most other organisms depend on autotrophs for ______and ______. Heterotrophic organisms that can’t make their own food may obtain nutrients by eating other ______. A heterotroph that feeds only on plants is called an ______. Herbivores are also called ______order heterotrophs. ______that feed on other herbivores are ______order heterotrophs. Carnivores that feed on other carnivores are ______order heterotrophs. A ______is a simple model of how ______and ______move through an ______.

Each level of production and consumption in a food chain is a ______level. The autotrophs form the ______trophic level, the herbivores the ______level, followed by second and third order heterotrophs.

In a pyramid of energy, the energy moves in only one direction and ______at each succeeding trophic level. The total energy transfer from one trophic level to the next is only about ______%. This is called the energy conversion transfer. The food consumers ingest is used to metabolize and build body tissues; some food is given off as ______. Energy lost at each trophic level enters the environment as heat.

A pyramid of ______is the weight of living ______at each trophic level. Biomass is calculated by finding the average weight of each species at that trophic level and multiplying the weight by the estimated ______of organisms in each population. In ______ecosystems, biomass decreases as the trophic level increases. In aquatic ecosystems, the biomass pyramid is inverted as phytoplankton and algae are more edible than land plants, have a shorter ______span and are more rapidly ______.

Table 1: Ecosystem Data

To complete the Table below follow these steps.

  1. List the organisms present in each ecosystem (i.e. hawks, snakes, etc.) under “Organisms”
  1. List the total number of organisms present at each trophic level in each ecosystem next to “Numbers:”
  1. List the total energy at each trophic level in each ecosystem under “Energy:”

Producers / First Order
Heterotrophs / Second Order
Heterotrophs / Third Order
Heterotrophs
Organisms:
Number:
Energy: / Organisms:
Number:
Energy: / Organisms:
Number:
Energy: / Organisms:
Number:
Energy:

Table 2: Energy Conversion Efficiency (ECE)

  1. The E.C.E. can be calculated by taking the energy value from a heterotrophic level and dividing it by the energy value of the level below it.

Example: First Order Heterotrophs / Producers multiplied by 100 = ECE % for First Order Heterotrophs

*Round all E.C.E. percentages to the whole number.

First Order Heterotroph / Second Order Heterotroph / Third Order Heterotroph
Decimal / % / Decimal / % / Decimal / %

Lab Questions:

  1. The ultimate source of energy for most ecosystems is:
  1. Carbon
  2. Oxygen
  3. Sunlight
  4. Water
  1. Organisms that directly use energy from the sun to make their own food are called:
  1. Autotrophs
  2. Heterotrophs
  3. Carnivores
  4. Decomposers
  1. Which of the following illustrates the correct ordering of trophic levels?
  1. Decomposerscarnivoresautotrophsherbivores
  2. Herbivoresautotrophscarnivoresdecomposers
  3. Autotrophsherbivorescarnivoresdecomposers
  4. None of the above
  1. Within an ecosystem:
  1. Energy flows in one direction only and nutrients are recycled
  2. Energy is recycled and nutrients flow in one direction only
  3. Energy and nutrients flow in one direction only
  4. Energy and nutrients are both recycled
  1. The efficiency of energy transfer from a lower trophic level to the next highest level is roughly:
  1. 1%
  2. 5%
  3. 10%
  4. 50%
  5. 80%

Analysis & Conclusion Questions:

  1. According to your data, what is the ratio of 3rd order consumers to producers? Explain your answer.
  1. Does the population size increase or decrease at higher trophic levels in a pyramid of numbers for an ecosystem of a tree, insects (herbivores), and birds feeding on insects? Explain your answer.
  1. Using the organisms from your data table, create one food chain starting with a producer and ending with a 3rd order consumer. Could you create a food chain without an herbivore and carnivore? Explain.