Biology 11 – Unit 3 Assignment 1. 2. 3. 4. 5. 6. Full Name: _Claudia Cristescu Virtual Lab: Model Ecosystems Post-Lab Quiz Please make sure you have read through all of the information in the “Question” and “Field Guide” areas. If you come upon terms that are unfamiliar to you, please refer to your textbook for further explanation or search the word here: http://encarta.msn.com/encnet/features/dictionary/dictionaryhome.aspx In this exercise, you will examine several model ecosystems and their characteristic plant and animal species. To begin, read the information in the “Field Guide” to learn more about the organization of five selected ecosystems. You are now ready to begin the activity. Start by selecting the ecosystem type that you would like to model from the pull down menu in the laboratory area. Then 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 and fix any incorrect choices if necessary. Clicking on the “Pyramid of Energy” will reveal how much energy is available at each trophic level. Clicking on the “Pyramid of Numbers” will show the number of organisms at each trophic level within this type of ecosystem. Fill in all of the information from this pyramid on Table I below. 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.), and this ratio is determined by taking the energy value from a higher trophic level and dividing it by the energy value of the level below it. Please do these calculations as directed and input the data in your “Data Table” and Table I below. When you are completely finished analyzing the ecosystem, you can then click the “Reset” button and select another type of ecosystem from the pull down menu. Follow the directions above to investigate this ecosystem and the three that remain. Please finish this exercise by opening the “Journal” link at the bottom of the page and answering the questions. Table I: Ecosystem Type Deciduous Forest Producers First Order Heterotrophs Organisms present: Chipmunk, deer, rabbits, chickadee, insects Energy:623 Numbers:4,559 E.C.E.*:0.0979 Second Order Heterotrophs Organisms present: Organisms present: Deciduous trees, ferns, Foxes, berry bushes, wild woodpeckers, owls, flowers, grasses opossums, snakes, Energy:6,011 frogs, toads, Numbers:7,996 Energy:61 E.C.E.*:0.1036 Numbers:1,418 E.C.E.*:0.0983 Hot Desert Organisms present: Organisms present: Organisms present: Cacti, ocotillo, rabbit Kangaroo rats, Tarantula, brush, sage brush, wild insects, herbivorous carnivorous lizard, flowers lizards snake Energy:200 Energy:21 Energy:2 Numbers:2,603 Numbers:831 Numbers:58 E.C.E.*:0.105 E.C.E.*:0.0952 E.C.E.*:0.095 Grassland Organisms present: Organisms present: Organisms present: Grasses, milkweed, Monarch Rattle snakes, gray lupine, butterflies, partridges, Energy:2,000 goldfinches, Energy:19 Numbers:549,106 pronghorns, Numbers:30 E.C.E.*:0.1115 buffalo, E.C.E.*: 0.1052 grasshopper Energy:223 Numbers:1,887 E.C.E.*:0,0852 Antarctic Organisms present: Organisms present: Organisms present: Ocean Shore Phytoplankton, Herbivorous fish, Carnivorous fish, Energy:8,006 squid penguin, seals, Numbers:5,478,000,000 Energy:784 Energy:86 E.C.E.*:1.00474 Numbers:5,504 Numbers:613 E.C.E.*:0.1113 E.C.E.*:0.0081 Freshwater Organisms present: Organisms present: Organisms present: Lake Algae, Water insects, Crayfish, frogs, Energy:7,500 minnows, ducks bass Numbers: 123,00 Energy:744 Energy:81 E.C.E.*:0.0987 Numbers:2,294 Numbers:55 E.C.E.*:0.1046 E.C.E.*:0.0992 *E.C.E.= energy conversion efficiency ratio Third Order Heterotrophs Organisms present: Wolves, hawks Energy:6 Numbers:50 E.C.E.*: Organisms present: Hawks, coyote Energy:0.19 Numbers:5 E.C.E.*: Organisms present: Coyotes, hawks Energy:2 Numbers:5 E.C.E.*: Organisms present: Killer whales, Energy:7 Numbers:5 E.C.E.*: Organisms present: Herons, Energy:8 Numbers:2 E.C.E.*: Post-laboratory Questions: 1. The ultimate source of energy for most ecosystems is: a. Carbon b. Oxygen c. Sunlight d. Water 2. Organisms that directly use energy from the sun to make their own food are called: a. Autotrophs b. Hetertrophs c. Carnivores d. Decomposers 3. Which of the following illustrates the correct ordering of trophic levels? a. Decomposerscarnivoresautotrophsherbivores b. Herbivoresautotrophscarnivoresdecomposers c. Autotrophsherbivorescarnivoresdecomposers d. None of the above 4. Within an ecosystem: a. Energy flows in one direction only and nutrients are recycled b. Energy is recycled and nutrients flow in one direction only c. Energy and nutrients flow in one direction only d. Energy and nutrients are both recycled 5. The efficiency of energy transfer from a lower trophic level to the next highest level is roughly: a. 1% b. 5% c. 10% d. 50% e. 80% 6. In aquatic ecosystems, biomass is least at which trophic level? a. Autotrophs b. Herbivores c. Carnivores 7. You are in an area where there are squid, seals and penguins. You are most likely in which ecosystem? a. Deciduous forest b. Hot Desert c. Antarctic Ocean Shore d. Grassland 8. You find yourself in an area where there are snakes, hawks and coyotes. Based upon these animal populations, you are most likely in which ecosystem? a. Deciduous forest b. Hot Desert c. Grassland d. You cannot tell from this information 9. You are in an area where the ground is littered with what appear to be dry, dead leaves. You are most likely in which ecosystem? a. Deciduous forest b. Hot Desert c. Grassland d. You cannot tell from this information 10. This zone has the greatest concentration of plankton in a freshwater lake ecosystem: a. Profundal b. Littoral c. Limnetic 1. Suggest reasons why the information represented in the pyramid of numbers of animals of one of the ecosystems you studied may not truly represent that ecosystem. Is not applicable because many more plant and animal species would be involved in a real world ecosystem. In addition, the numbers are constantly changing. 2. According to your data, what is the ratio of third-order consumers to producers? Explain your answer. Taking in consideration that only around 10% of the energy gained from the previous trophic level is transferred to the next trophic level, the ratio of third-order consumer to producer is 100:1. 3. Compare and contrast two of the ecosystems you studied. How is the energy conversion efficiency similar or different? Deciduous forest and hot desert share an almost similar energy conversion efficiency of all trophic levels, as well as some similar plant and animal species, such as wild flowers, hawks and snakes. 4. Does the population size increase or decrease at higher trophic levels in the pyramid of numbers of an ecosystem consisting of a tree, insects (that are herbivores) and birds feeding on the insects? Explain your answer. Since there high trophic levels depend on the primary producers and lower trophic levels for food and energy, there must be a very large number of producers to sustain the rest of the pyramid. 5. What might happen to an ecological pyramid of numbers in a forest ecosystem if most of the deer were killed due to hunting by people and disease? If most of the deer were killed, the deer dependent species at a higher trophic level would struggle with finding prey and would eventually die of starvation and become extinct. The third order species would be affected as well since their prey would vanish. 6. What would happen to an ecosystem if the decomposers disappeared? The soil would be highly affected if decomposers disappeared and dead bodies would not be decomposed. The producers would not be able to grow from the soil and each trophic level would be affected since primary consumers would die of starvation. 7. Could there be a food chain without herbivores and carnivores? There would be no energy flow and no food chain with only one trophic level of producers without any herbivores and carnivores. The producers will overpopulate and there would be no dead bodies for the decomposers and for the soil to get its nutrients.
