Creating Chains and Webs to Model Ecological Relationships

Name: __________________________________________ Period: ___________ CREATING CHAINS AND WEBS TO MODEL ECOLOGICAL RELATIONSHIPS OVERVIEW You will identify producers and consumers in the savanna ecosystem of Gorongosa National Park in Mozambique. Using a set of “Gorongosa cards,” you will then create a food chain to show the flow of energy in that system, introduce an ecological force or disturbance (e.g., fire), and predict how that force would impact energy flow. Lastly, you will construct a more complex model of the flow of energy by depicting multiple relationships in a food web and again make a prediction about the impact of introducing an ecological force. INSTRUCTIONS You will receive a set of cards that depict some common animals, plant types, and ecological forces or disturbances from the savanna ecosystem in Gorongosa. Use the cards to build models and answer questions as directed on this worksheet. After building a food chain or food web with the cards, record your version by writing the organism names in the appropriate spaces on the worksheet and connecting them with arrows. Part 1: Creating a Food Chain Using the organism cards, sort them into two piles that represent producers and consumers. 4 1. How many producers do you have? _________ 2. How many consumers do you have? _________ 14 3. A food chain is a model that identifies the feeding relationships and the flow of energy in an ecosystem. Select a producer and a consumer from your piles, then fill in the blanks below and select which model (A or B) correctly shows the flow of energy. A. Impala _______________ _______________ Cenchrus ciliaris Consumer Producer or B. _______________ _______________ Switch grass Elephant Producer Consumer 4. Justify why you chose A or B as the correct model. Model A because consumers (animals) eat producers (plants). Producers cannot eat consumers except for a few small exceptions. Like venus fly traps against flies, or the process of decomposing which is a completely different process. 5. Select four cards to create a food chain, starting with a producer. Label the trophic level of each organism in your food chain as follows: producer, primary consumer, secondary consumer, tertiary consumer. Record your food chain in the space below using species names and arrows. Cenchrus ciliaris ---> Grasshopper ---> Shrew ---> Serval (Producer) (Primary consumer) (Secondary consumer) (Tertiary consumer) Part 2: Available Energy at each Trophic Level Only a small fraction of energy available at any trophic level is transferred to the next trophic level. That fraction is estimated to be about 10 percent of the available energy. The other 90 percent of the energy is needed by organisms at that trophic level for living, growing, and reproducing. This relationship is shown in the energy pyramid above. It suggests that for any food chain, the primary producer trophic level has the most energy and the top trophic level has the least. 6. Why is a pyramid an effective model for quantifying energy flow? Because it categorizes different types of producers and consumers into a hiearchy. It makes sense that the higher the trophic level the less energy there is. It is important to have a better understanding of energy transfer, especially when simplified into this relationship. 7. Place the organisms from your original food chain on the pyramid provided. Serval Shrew 13kg 50g Grasshopper Cenchrus ciliaris 8. Using the rule of 10 percent in energy transfer, record the species names for each trophic level and the amount of energy available at that level if your producer level had 3,500,000 kilocalories of energy/area. 3,500,000 > 350,000 > 175,000 > 455,000 9. In one or two sentences, describe how the available energy may affect the population sizes of organisms at different trophic levels. The available energy determines the food supply for each consumers consumption. The available energy affects the population sizes of organisms on trophic levels above and below them. Part 3: Creating a Food Web Food chains are simple models that show only a single set of energy-transfer relationships, but most organisms obtain energy from many different sources and, in turn, may provide energy to several different consumers. A food web illustrates all these interactions and is a more accurate model of how energy moves through an ecological community. 10. Starting with your original food chain (question 5), add another plant and four more animal cards to construct a food web that shows how energy flows from producers through primary consumers, secondary consumers, tertiary consumers, and possibly a quaternary consumer. When making your food web, you can have more than one arrow leading to and from each organism. Draw a version of your food web below. Serval Shrew Lion Hare Zeb Kudu assho Cenchrus ciliaris Leaves Coral tree 11. In two to three sentences, describe any patterns you notice in the relationships between trophic levels. Every trophic levels except for producers always consume/hunt energy below them in the trophic levels. Plants gain energy from sunlight, primary consumer gain energy from plants, secondary consumers eat primary consumers, and tertiary consumers eat secondary consumers. Humans are at the top (-: Now read your disturbance card and predict its impact on your food web. Complete the table below: Drought No more healthy vegetation No water holes Plants do not receive enough water and die out. Weather changes Impacted ecosystem Deforestation Increasing human population Loss of habitation Unable to hide from predators No place for primary consumers to hide, habitat, and Seasonal changes less plants to eat. Less camoflauge and more Ruined agrilculture vulnerable to predators. Higher demand for animal meat Less land for animals to roam More animals die. Increased hunting and poaching, Blocked migration paths smaller ecosystems, less land for animals to habitat. Increased poaching War Significant rate of poaching Animals lose homes Damaged environments Migration patterns change Many animals will be impacted by humans at war. They are poached for their meat, fur, skin and more. Especially elephants, poached for their tusks. 12. Describe whether some trophic levels benefit from the disturbance while others do not. If humans caused the disturbance, was it negative or positive for each trophic level in the food chain? Negative. There is no benefits to any trophic levels when disturbances are caused. Sure, hunting would probably be easier for tertiary consumers if secondary consumers lost habitats, but at the same time this would greatly have an on the balance of the trophic levels in the long run. The most successful trophic levels are ones that are balanced a stable. A great disturbance in it means most trophic levels have to adapt around it. Not to mention, many people are concerned of animal extinction for this reason. To prevent a disturbance in the trophic levels. Part 4. Model evaluation In science, models are used to represent explanations and predications. The food chain, food web, and energy pyramid are all models that show feeding relationships and allow us to make predictions. Compare and contrast the strengths and weaknesses of each model by filling in the table below. is a bit flat and vague. Leaves out a lot of details Simple display of specific producers and consumers,It what seems it only goes in a straight line and each order they go in etc. consumers only prey on things below them. Gets the point across quite well. Great for introducing the food chain as it is easily comprehendable. Probably the best one out of all. Includes energy transfer, Not flawed at all. It depends on how much you kno and shows the higher the trophic levels the less energy and how much information you are willing to uncov transfers over. Secondly, the energy pyramid cateogorizes either studying or researching more information. producer and shows there are three different types of consumers. Shows each consumers eat more than one thing. StillA step above the food chain. You are able to infer a establishes a hierarchy. Feels like a 3D version of thefrom foodit. You can form ideas and write sentences ba chain in a way. on it. Lacks certain knowledge that the energy pyra Adds more in-depth view to what consumers eat. It gives has. more information than the food chain. 13. Select the model that you think is most effective in representing relationships among organisms in the Gorongosa ecosystem and justify your choice in two or three sentences. The energy pyramid. It is very special and unque compared to the rather blend food chain and food web. There a hierarchys in the energy pyramid, and shows that energy transfer divides by 10% the higher the trophic levels go really enjoyed the in-depth explanation of energy being lost. Very informative in knowledge.