Create Your Own Food Web

Transcription

1 Create Your Own Food Web Introduction: Chaparral is a shrubland ecosystem found primarily in the southern state of California and in the northern portion of the Baja California peninsula, Mexico. It is shaped by a Mediterranean climate (mild, wet winters and hot dry summers) and wildfire, featuring summer drought-tolerant plants with hard sclerophyllous (short, hard) evergreen leaves. Big Ideas (Core Concepts): Energy transformations from the Sun to organisms provide energy for all life forms to exist. Matter transfer in ecosystems between living and non-living organisms provides the materials necessary for all life. Matter and energy are conserved in ecosystems, although their transformations are not efficient. Goals/Objectives: 1. B3.2A - Identify how energy is stored in an ecosystem. 2. B3.2B - Describe energy transfer through an ecosystem, accounting for energy lost to the environment as heat. 3. B3.2C - Draw the flow of energy through an ecosystem. Predict changes in the food web when one or more organisms are removed. B3.3A - Use a food web to identify and distinguish producers, consumers, and decomposers and explain the transfer of energy through trophic or feeding levels. 4. Show the energy flow through a food chain by constructing model food chains and food webs with the given drawings of organisms found on the Chaparral. Materials: Organism sheets (See pages 2 and 3). Each picture also has information on what the organism eats. o Plants of the Chaparral o Insects of the Chaparral o Animals of the Chaparral Scissors Glue or tape Paper Procedure: 1. Using colored pencils, lightly color your cards using the following color code a. The sun is yellow. b. Decomposers are brown. c. Producers are green. d. Herbivores are blue. e. Omnivores are orange. f. Carnivores are red. g. Scavengers (spotted skunk and mountain coyote) are purple. 2. Use scissors to cut the pictures apart (See pages 2 and 3). 3. Sort the pictures into groups according to energy sources; producers, herbivores (primary consumers), secondary consumers, tertiary (3 rd order) consumers, scavengers and decomposers. 4. Construct 4 food chains as they would occur in the chaparral by first arranging them on your desk. 5. Use the same pictures to form a chaparral food web by first arranging them on your desk. Remember that a food web is several food chains linked together. Arrows indicate the direction of energy flow and the arrows go from the animal that is eaten to the animal doing the eating. Have your instructor approve your food web before you glue or tape your cutouts to a large sheet of paper. 6. Glue or tape your food web to a large sheet of paper. Again use arrows to show that energy is passed from one living organism to another. ** Challenge: Can you make a large food web using the energy source and ALL of the living organisms from pages 2 and 3? Go for it! 1

2 Chaparral Plants/Decomposers/Energy Source Chaparral Insects/Spiders 2

3 Chaparral Vertebrates 3

4 Real World Context: Life is comprised of many complex cellular processes that occur in all organisms, including plants and animals. These processes include: the transport of materials, energy capture and release, protein building and waste disposal. The flow of energy into ecosystems is from the Sun to producers through the process of photosynthesis. Producers are able to use this energy to convert carbon dioxide, a gas, and water into energy-rich, highlycondensed carbon compounds, usually carbohydrates. Plants may then use these materials for their own cellular energy needs by the process of cellular respiration. Consumers also obtain usable energy from the biochemical breakdown of carbohydrates and molecules derived from them during respiration. In this way, derived directly or indirectly from a plant source, carbohydrates are foods that, when converted into waste materials, yield usable energy for the organism in the process of cellular respiration. Ultimately, nearly all organisms will be subjected to breakdown by decomposers, who themselves convert mass into waste materials, using the derived energy. When consumers eat plants or other consumers, they are transferring matter, in the form of flesh, through an ecosystem. Energy is also being transferred as it is stored in the chemical bonds that bind the food molecules together. As this energy is transferred through ecosystems, liberated for organismal use by cellular respiration, conversions are not entirely efficient and heat is lost as a by-product at each step, dissipated into the environment, leaving less usable energy available to each successive trophic or feeding level. Organisms may be classified as producers, consumers and decomposers, based on their feeding relationships within their particular food web. These food webs may be from ecosystems that are widely represented in textbooks and of importance to all students, even if they do not live near them. Changes in relationships and populations of producers and consumers may occur as the result of the loss of one or more types of organisms in the ecosystem. The loss of any group of organisms from an ecosystem changes the flow of energy within that system. The overall cycling of matter, specifically carbon and nitrogen, through ecosystems as it passes between living systems to abiotic components of ecosystems is very important because it shows the interdependence of organisms with their physical environment, and vice versa. Human created disturbances in ecosystems or environments, including local and global climate change, uses of tilling and pesticides to favor human crops, human land use, harvesting of fish stocks, pollution, invasive species, and others are common to many ecosystems and represent problems that cause imbalances in the cycling of matter and the transformation of energy through ecosystems. 4

5 Name Questions: 1. What is the ultimate source of energy for the photosynthetic producers in the Chaparral ecosystem? 2. How is energy stored in living organisms? Hint: Unit #2 Ch. 6 Chemistry p How does the amount of available chemical energy change as you move from one trophic level to the next in a food chain or food web? Does the amount of available energy increase, decrease, or stay the same? Explain your answer by using sentences, a food chain/web, or an energy pyramid. 4. For each of the following terms, identify one organism in your food web that has that role in the web and explain why it fits the term (i.e., why it is called an herbivore, for example be specific). a. Producer b. Primary Consumer c. Secondary Consumer d. Tertiary Consumer e. Herbivore f. Carnivore g. Omnivore h. Decomposer 5

6 5. Compare and contrast a food chain and a food web (list 2 similarities and 2 differences). 6. What would likely happen to the other organisms in the web if the producers disappeared? Be specific based on your food web. 7. Would there be more predators or prey in a particular community? Explain. 8. Explain what may happen to the other organisms if disease were to kill off one of the 2nd level carnivores in your food web. Which organisms would increase in population? Why? Which organisms would decrease in population? Why? 9. Describe how humans might change (or are currently changing) the food web. 10. Why can't food chains go on forever? (8th order, 9th order and 10th order consumers?) 6