Field of Beans Determining the Interactions of Organisms

Field of Beans Determining the Interactions of Organisms An ecosystem consists of all of the organisms that are living in a community as well as the abiotic factors in which they interact. The combination of many different ecosystems across a wide space of land is called a biome. In the biosphere we call Earth there are several major biomes: tundra, taiga, deciduous forest, grasslands, tropical rainforest and desert. In this activity you will investigate the interactions of the organisms, energy flow through the trophic levels, and population sizes in a particular biome. GLOSSARY Population sampling The process through which a group of representative individuals is selected from a population for the purpose of predicting the entire population. Random sampling A method of population sampling where sample sites are selected at random to be counted.- Food chain A simple model that shows how matter and energy move through an ecosystem. Food web A complex network of many interconnected food chains and feeding relationships. Energy pyramid An ecological pyramid illustrating the energy flow within an ecosystem. Pyramid of numbers An energy pyramid that illustrates the flow of energy in an ecosystem as well as the number of organisms in a given population, species, or trophic level. Pyramid of biomass An energy pyramid that illustrates the flow of energy in an ecosystem as well as the biomass of the entire population, species, or trophic level. Trophic level A position in a food chain or energy pyramid occupied by a group of organisms with a similar feeding mode. Consumer/Heterotroph An organism that is unable to synthesize its own organic food source, hence, feeds on organic matter produced by other organisms. Producer/Autotroph An organism capable of making organic molecules from inorganic sources through a process known as photosynthesis or chemosynthesis. Decomposer/Saprotroph An organism that feeds on the excrement, dead bodies or tissues of others. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 1

ANIMAL DESCRIPTIONS Coyotes are very similar to a wolf and are usually off-white in color. Coyotes are mainly carnivores, but they will eat fruit and insects. The carnivorous part of their diet includes small mammals and nesting birds. They are typically a secondary or tertiary consumer. Kangaroo rats run by leaping or hopping on large hind feet. They can survive without ever drinking water, getting needed moisture from their seed diet. There are many creatures that eat the Kangaroo rat in this biome. Bobcats are nocturnal. They are usually light brown to reddish brown and have very short tails. They eat hares, rabbits, and other small mammals. As a result of their varied diet, they are a top level consumer. Western rattlesnakes venomous snakes that inhabits open rocky ground. They eat rodents, small birds, toads and frogs; therefore, they are considered a tertiary consumer. They get their name from the rattle at the end of their tail. Texas horned lizards small reptiles that are preyed upon by hawks and large snakes. As a defense mechanism they are able to squirt blood from their eyes. Their primary source of food is small insects and they are often found alongside ant trails. They are considered secondary consumers. Praying mantises carnivorous insects that take a deceptively humble posture when searching for food. When at rest, their front legs are held up together in a posture that looks like they are praying. They are typically pea green to brown in color. Ants ground dwelling insects usually found in large numbers in lines. They live in large colonies sometimes described as super-organisms because they appear to operate as one. Most ants are herbivores but some are scavengers. Gopher tortoises are cold-blooded reptiles that can live up to 60 years. Gopher tortoises are accomplished burrowers and tend to share their burrow with burrowing owls, rattlesnakes, insects, and tarantulas. Their diet consists of low growing grasses and herbs. Grasshoppers use camouflage to aid in their survival. They have the ability to either hop or fly. Their primary food source is grass. Southern plains woodrats large, gray-colored rats with large ears and a relatively short, heavy, sparsely-haired tail. They are usually found associated with cactus or some of the thorny desert shrubs. Their food consists of the prickly pear and the juicy fruits of many species of cactus. Red-tailed hawks birds of prey, commonly called chicken hawks. They are a carnivorous feeder mainly on small mammals, birds, and reptiles. They typically are a quaternary consumer. Burrowing owls are small, long legged owls that live in deserted rodent burrows. Unlike most owls, they are often active during the day although they tend to avoid mid-day heat. The highly variable diet includes large insects and small rodents. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 2

Northern grasshopper mice rodents about the size of a small hamster. As their name suggests, grasshopper mice eat grasshoppers. They also eat other insects, lizards, spiders, and even other mice. Texas toads are effective burrowers that tend to be nocturnal. Toads have enlarged glands on the side of the neck that secrete a white poison in the mouth of a predator. Their diet consists mainly of insects and other invertebrates. Detritus Dead plant and animal material. Cacti, mesquite trees, and grasses These organisms are photosynthetic. Bacteria and Fungi These organisms carry out large portions of the nitrogen cycle. Ants Bobcat Coyote 1 bean = 250 ants Bacteria and Fungi Gopher tortoise Burrowing owl Grasshopper Red-tailed hawk Southern plains woodrat Kangaroo rat Western rattlesnake Texas horned lizard Northern grasshopper mouse Praying mantis Texas toad Cacti, mesquite trees, etc. Detritus Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 3

Extra set for participants to cut out. Ants Bobcat Coyote 1 bean = 250 ants Bacteria and Fungi Gopher tortoise Burrowing owl Grasshopper Red-tailed hawk Southern plains woodrat Kangaroo rat Western rattlesnake Texas horned lizard Northern grasshopper mouse Praying mantis Texas toad Cacti, mesquite trees, etc. Detritus Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 4

PURPOSE To estimate the size of various populations, create a food web, and construct pyramids of energy for organisms in a given biome. MATERIALS bag of beans containing identification bags glue stick 10 10 cm index card ruler 1 1 meter piece of butcher paper highlighter calculator colored pencils PRELAB Below is an area of land behind a local high school. Rather than send 100 students out to count the organisms in the entire area, the teacher sent 5 to randomly sample the population. Students counted the organisms in the labeled sections. 1. Determine the size of the population using random sampling. 2. Compare your estimation to the actual size of the population. 3. List two ways to improve this method of sampling. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 5

4. In a forest that measures 5 miles by 5 miles, a sample was taken to count the number of red oak trees in the forest. The number of trees counted in the grid is shown below. The grids where the survey was taken were chosen randomly. Determine how many red oak trees are in this forest using the random sampling technique. 5. Draw a general pyramid to represent the food chain below. You may draw a triangular pyramid or a pyramid composed of rectangles. Grass Grasshopper Snake Hawk Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 6

6. Draw a food chain to represent the food pyramid. 7. Use the data table to create a pyramid of numbers. 8. Use the biomass data to create a pyramid that shows the biomass. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 7

PROCEDURE PART I INTRODUCING THE FIELD OF BEANS 1. Your teacher will provide you with pictures of each of the organisms to be used during this investigation. You will also be given a description sheet that describes each organism. 2. Using this information, construct a food web in the space provided on your student answer page. Be sure to place the producers toward the bottom of the web and the top level consumers toward the top. 3. Create a color key for the arrows that exist in your web. A sample is below. Energy Relationships Producer to primary consumer Primary consumer to secondary consumer Secondary consumer to tertiary consumer Tertiary consumer to quaternary consumer Quaternary consumer to fifth level consumer Color PART II SAMPLING THE FIELD OF BEANS 1. Your teacher will provide you with a baggie containing your field of beans. 2. Spread out the contents of the baggie onto a large piece of butcher paper. Remove the small bags and the 10 cm 10 cm index card. Set them to the side. 3. Try your best to space out the beans evenly across the paper. 4. Take the index card and drop it onto the field of beans. 5. Once the card lands, trace around the card to outline the area that it covers. Try not to disturb any of the beans surrounding the card. In the event that a bean is half-way under the card, your group needs to decide whether to count that organism as being under the card or not. This will be sample site 1. 6. Remove the card and using the bean identification bags, identify and count all of the organisms in this sample site. Record the data in Data Table 1 on your student answer page. Note that for the grasshoppers, plants, and ants, each bean counted in the field represents a large number of organisms. (1 ant bean = 250 ants, 1 grasshopper bean = 100 grasshoppers, and 1 plant bean = 200 plants) 7. Once again randomly drop the index card onto the field of beans. Trace around the perimeter of the card. In true random sampling, sample sites do not typically overlap. If the card drops on a sample site that has already been counted, pick the card up and drop it again. Repeat steps 5 and 6 for this new sample site. 8. Continue this process for a total of 10 sample sites, counting the beans at each site. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 8

9. Once you have counted all of the organisms in each of the 10 sample sites, find the AVERAGE number of each type of organism and record it in Data Table 1 on your student answer page. 10. Remembering that the small sample site is 1/100 the size of the entire field, use your averages to estimate the total of number of organisms in the field. PART III CONSTRUCTING THE PYRAMIDS 1. Using your food web, locate a food chain that consists of at least 5 trophic levels. 2. On your student answer page, draw the food chain. Remember to color the arrows accordingly. 3. Using the food chain, you are going to construct two pyramids. The first is a pyramid based on the total number of organisms that you counted in Part II of this activity. 4. Transfer the total number of organisms that you calculated in Data Table 1 into Data Table 2 under the column labeled Total Number. 5. Using a highlighter, highlight the rows that contain the organisms that you selected in your food chain. 6. Construct your pyramid of numbers by starting with the bottom layer, in this case, the producers in your food chain. Draw the bottom layer of the pyramid as a rectangle. Continue to draw the remaining layers proportional to the previous layer. 7. Next, construct a pyramid of biomass. In order to do this, first calculate the biomass of each population using the following equation: Biomass = Number in Population Average Mass of Organism 8. Data Table 2 provides the average mass of each organism. Multiply the mass times the number of organisms that you estimated to be in the population. 9. Again, start constructing this pyramid with the bottom layer. Continue to draw the remaining layers proportional to the previous layer. Remember to keep the layers in order of the food chain regardless of the size of the layer. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 9

Field of Beans Determining the Interactions of Organisms DATA AND OBSERVATIONS In the space below construct your food web. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 10

Ants * Bobcat Organism Burrowing owl Cacti and century plants ** Coyote Gopher tortoise Grasshoppers *** N. grasshopper mouse Ord s kangaroo rat Praying mantis Red tailed hawk Southern plains woodrat Texas toad Texas horned lizard Western rattlesnake *1 ant bean = 250 ants ** 1 plant bean = 200 plants *** 1 grasshopper bean = 100 grasshoppers Data Table 1 Sample Site 1 2 3 4 5 6 7 8 9 10 Avg. Total Number 100 Organism Ants * Bobcat Burrowing owl Cacti, mesquite trees, century plants ** Coyote Gopher tortoise Grasshoppers *** Northern grasshopper mouse Ord s kangaroo rat Praying mantis Red tailed hawk Southern plains woodrat Texas toad Texas horned lizard Western rattlesnake Data Table 2 Total Number Mass 0.5 g 13,607 g 155 g 600,000 g 13000 g 125 g 2 g 40 g 80 g 2 g 900 g 7 g 10 g 13 g 700 g Biomass = Total # Mass Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 11

CONCLUSION QUESTIONS 1. Identify the biome that the organisms most likely belong to and justify your answer. 2. In order for the plants and animals to survive in this biome, they have adapted over many years. Describe a minimum of two adaptations of the flora and the fauna in this biome. 3. What organism is the top energy level in your food web? 4. Which organism has the most numerous sources of food? List the organism and food sources. 5. List any organism that has a single food source, and make a prediction as to what would happen if the food source for the organism you listed is removed. 6. Explain the steps of the process that happens to dead plant and animal material? 7. A local student purchased a pair of large rats to keep as pets. Over the next several months, the rats had 12 babies. The student could no longer keep up with all of the babies, so he released them into this biome. Identify 2 other organisms that will be impacted by this new population and explain how they would be impacted. Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 13

8. Describe how a natural disaster, like a drought or grass fire, would affect an herbivore, carnivore, and an omnivore in this biome. 9. Symbiotic relationships exist throughout our biome. Name at least two symbiotic relationships that exist and describe the type of relationship that they have. 10. The table below contains the actual number of organisms in your biome. How accurate were your totals that you calculated? Explain 2 things that could have been done to improve your sampling accuracy. Organism Actual Number Ants 10,000 Bobcat 1 Burrowing owl 10 Cacti, mesquite trees, century plants 25,000 Coyote 1 Gopher tortoise 30 Grasshoppers 10,000 Northern grasshopper mouse 40 Ord s kangaroo rat 50 Praying mantis 60 Red tailed hawk 2 Southern plains woodrat 40 Texas toad 60 Texas horned lizard 150 Western rattlesnake 2 Copyright 2010 Laying the Foundation, Inc. Dallas, TX. All rights reserved. Visit: www.layingthefoundation.org 14