Food Web Construction and Manipulation - Mater Academy 材料学院食品网站的建设和操作

1、.Designing & Manipulating Ecological Energy DiagramsObjectives:· Use a food web to identify and distinguish producers, consumers, and decomposers. Explain the pathway of energy transfer through trophic levels and the reduction of available energy at successive trophic levels. AAPurpose of t

2、he Lab/Activity:· Differentiate between a food chain and food web.· Identify and distinguish the main components of an ecosystem.· Explain the pathway of energy through trophic levels.· Analyze the reduction of energy available at successive trophic levels.Prerequisites:· Un

3、derstand the role of photosynthesis in ecosystems.· A general sense of the major groups of organisms in order to help determine their role and habitat.· Know the law of conservation of energy.Problem Statement: Are food chains and food webs the same? How do organisms transfer energy?Backgr

4、ound: (Source: )All organisms in an ecosystem need energy to survive. This energy is obtained through food. Producers obtain energy by making their own food whereas consumers must feed on other organisms for energy. This dependence on other organisms for food leads to feeding relationship

5、s that interconnect all living things in an ecosystem. A food chain illustrates the simplest kind of feeding relationship. For example, in a forest ecosystem, a grasshopper feeds on plants. The grasshopper is consumed by a spider and the spider is eaten by a bird. Finally, that bird is hunted by a h

6、awk. A food chain clearly shows this pathway of food consumption.You could probably think of another food chain for a forest ecosystem. In fact, many different food chains exist in ecosystems. Although there are many different kinds of food chains, each food chain follows the same general pattern. A

7、 link in a food chain is called a trophic, or feeding level. The trophic levels are numbered as the first, second, third, and fourth levels, starting with the producers.Each of the trophic levels is occupied by a certain kind of organism. Producers are always in the first trophic level since they do

8、 not feed on another organism. Consumers occupy the rest of the trophic levels. The second trophic level is the first consumer in the food chain and is called a primary consumer. Primary consumers eat plants and are therefore herbivores or omnivores. The next consumer in the food chain is the second

9、ary consumer. The secondary consumer is in the third trophic level. Since the secondary consumer feeds on another animal, it is a carnivore or an omnivore. Similarly, the tertiary consumer occupies the fourth trophic level, and is a carnivore. The last link in a food chain is also referred to as the

10、 top carnivore since it is at the top of the food chain and is not hunted by other animals.Vocabulary: food chain, food web, food pyramid, producer, consumer, decomposer, detrivore, herbivore, carnivore, energy transfer, trophic levelExtension: Food Chain Gizmo & Pet Pythons Gone Wild VideoMater

11、ials (per group):*;· One set of cards· Colored Pencils· 3 large cardboard papers · Glue sticks· Scissors· Marker· Pen/pencilPre-Lab: 1. Why does the arrow in a food chain point towards the animal that eats the food?2. Compare/contrast between a food web and food ch

12、ain.3. Compare/contrast between a pyramid of numbers, energy, and biomass? 4. About what percentage of energy, mass, or numbers go up to the next trophic level? Where does the rest go?5. Define the vocab items6. Draw / get 3 pictures of each of the animals that will be required on the food web Proce

13、dures:Food Web Creation BoxMouseEats:GrasshoppersSnailsSalt marsh plantsRatEats:SparrowsGrasshoppersSnailsSalt marsh plantsOwlEats:RatsSparrowsDuckssandpipersMushroomDecomposes dead land animalsHawkEats:ShrewsMiceratsDuckEats:CrustaceansSalt marsh plantsAlgaeGrasshopperssnails SandpiperEats:Crustace

14、ansalgaeBacteria:Decomposes organic matter back into basic nutrientsSparrowEats:CrustaceansSalt marsh plantsGrasshopperssnailsShrewEats:GrasshoppersSnailsmiceSmall CrustaceanEats:Salt water algaeEarthworm:Consumes large chunks of dead matter in the soilFishEats:CrustaceansSalt marsh plantsSalt water

15、 algaeHeronEats:FishGrasshopperEats: Salt marsh plantsSalt water algae:Energy Source:SunlightCO2Basic NutrientsSalt marsh plantsEnergy Source:SunlightCO2Basic NutrientsSnailEats:Salt marsh plantsSalt water algaeNote: All organisms will need water and oxygen (except perhaps bacteria). You may exclude

16、 these from the web for simplification purposes.1. Take out pictures representing the animals in the food web2. Food Web: Using the table above as reference. Arrange the cards into a logical food web, being sure to draw the arrows (pencil) in the appropriate direction showing energy flow. Once you a

17、re sure of your design do the following steps:a. Use colored pencils to write animal names under the pictures. Names should be color coded as follows:· Green = Producers· Blue = Herbivore· Yellow = Omnivores· Red = Carnivore· Black = Decomposers · Orange = Detrivore

18、3; Also underline any animals that are considered scavengersb. Use color pencil to color code arrows· Green = Arrow represents link between basic nutrient and a producer, or energy exchange between abiotic factors and biotic factors· Blue = Arrow represents primary consumption, or energy e

19、xchange between a producer and a consumer· Yellow = Arrow represents secondary consumption, or energy exchange between a primary and a secondary consumer· Orange = Arrow represents greater than secondary consumption (tertiary or higher), or energy exchanges between higher trophic levels

20、83; Black = Arrow represents a nutrient recycling step taken by detrivore or decomposer3. Food Chain: Using the second set of pictures and the same color-coding as above (base it on information table and on the food web you designed), create a diagram that shows at least 6 different chains in the ec

21、osystem. Use as many of the pictures as you can, but save 1 picture of each animal for the next part. If you run out of pictures (already used animal and want to use it again), try using a different chain or draw it again. 4. Trophic Levels Through a Energy Pyramid: Using the third set of pictures,

22、create a food pyramid with the animals. Remember to place all producers in the bottom level. On the next level, place primary consumers (eat only producers). On the third level, place any organism that eats primary consumers. On the fourth level, place any organisms that eat those, etc. Note: Some o

23、rganisms are at different trophic levels depending on which chain you look at it. For the purpose of this activity. Place the animal on the highest level it occupies. 5. Show your web, chains, and pyramid to your teacher. You will need to present / explain it so practice with another group first. 6.

24、 The teacher will then kill off one of the species in your web.7. On a separate sheet of paper, discuss the impacts of the extinction of this species. How will their death impact the animals who feed on them? How will it affect the species that were preyed upon by them?Discussion Questions1. What do

25、es the suffix “troph” mean? 2. What do you think a trophic level is?3. Give an example of an animal that occupies different trophic levels depending on which food chain you look at. Write down the chains to illustrate your point. 4. Explain what would happen if all of the primary consumers became ex

26、tinct. 5. Predict what would happen if a non-native species is introduced into the food web. 6. Explain why food webs with many species (biodiverse) are more resilient than those with few species. 7. Review your trophic pyramid, do you think there are more organisms at the base and less organisms as you travel up the pyramid (ignore the variety of types and think of quantity of numbers). Why is this the case? 8. Where is there more energy available at the bottom or at the top of the food chain / energy pyramid? Explain your answer9. Based on your knowledge about energy levels in the e