Factors That Influence Ecosystems

Transcription

1 Name Class Date Skills Practice Lab MATH/GRAPHING Factors That Influence Ecosystems Ecosystems are communities of plants, animals, and other organisms that live and interact with each other and with nonliving environmental factors. The nonliving factors, or conditions, include temperature, precipitation, altitude, and latitude, among others. These factors play an important role in determining what types of vegetation can live in an ecosystem. Latitude, for example, has a strong influence on an area s temperature, resulting in climates such as polar, tropical, and temperate. These climates determine different natural biomes that have characteristic species of plants. However, a careful look at a map reveals that ecosystems existing at the same latitude often have different climates. Why? In this laboratory activity, you will hypothesize how other nonliving factors influence the characteristics of ecosystems within the same latitude range. Then you will analyze and graph data from different areas of the United States to test your hypotheses. OBJECTIVES Hypothesize how precipitation and altitude affect the types of vegetation in an ecosystem. Graph and analyze ecosystem data to confirm or refute your hypotheses. MATERIALS colored pencils metric ruler Procedure 1. Form two hypotheses one that relates differences in ecosystem vegetation to rainfall and another that relates differences in ecosystem vegetation to altitude. Complete the following sentences to form your two hypotheses. Ecosystem distribution is related to precipitation; regions that receive large amounts of precipitation are wet and therefore. Ecosystem distribution is related to altitude; regions at high elevations are cold and therefore. Holt Environmental Science 30 Biomes

2 Name Class Date Look at the data table. The table lists major U.S. cities and weather stations between 36 north and 41 north latitude. It also lists the altitude, average annual precipitation, and ecosystem for each location. On the graph/grid on the following page, use one of your colored pencils to plot altitude for each location using the left-hand y-axis. Connect the data points. Plot the precipitation data in another color, using the right-hand y-axis, and connect the points. You may also find it useful to label the location names on the grid above your data points. Your completed line graph will help you interpret any relation among rainfall, altitude, and biome type. CHARACTERISTICS OF LOCATIONS ACROSS THE U.S. Distance from Altitude above Average Natural San Francisco sea level rainfall biome or (miles) (feet) (in./yr.) ecosystem San Francisco, CA redwood forest Sacramento, CA grassland Donner Pass, CA 200 7, coniferous forest Reno, NV 250 4,400 8 cool desert Salt Lake City, UT 650 4, cool desert Loveland Pass, CO , coniferous forest Denver, CO 950 5, short grass prairie Topeka, KS 1, tall grass prairie St. Louis, MO 1, broadleaf forest Cincinnati, OH 2, broadleaf forest Washington, D.C. 2, broadleaf forest Analysis 1. Identifying Patterns Which types of ecosystems occur in areas of high and low precipitation? Holt Environmental Science 31 Biomes

3 Name Class Date Annual rainfall (inches) 15,000 10,000 5,000 4,000 3,000 2,000 1,000 0 An Ecological Transect Across the United States San Francisco 500 1,000 1,500 2,000 2,500 Distance in miles from San Francisco Altitude (feet) Holt Environmental Science 32 Biomes

4 Name Class Date 2. Examining Data Is there a trend in the amount of precipitation from Denver to San Francisco or from Denver to Washington, D.C.? If so, describe it. 3. Analyzing Results How do mountain ranges affect precipitation? Give an example that supports your answer. Conclusions 4. Evaluating Data Which is the more important factor in determining an area s ecosystem, the amount of precipitation or altitude? Is there an interaction between these two factors? Explain. 5. Defending Conclusions Does the data support or refute your hypotheses about the effects of precipitation and altitude on an ecosystem type? 6. Applying Conclusions Refer to the world biome map in your textbook. Examine the ecosystem patterns of the Eurasian continent. What can you infer about the distribution of rainfall in Eurasia? Holt Environmental Science 33 Biomes

5 Skills Practice Lab MATH/GRAPHING Factors That Influence Ecosystems Teacher Notes TIME REQUIRED One 45-minute period SKILLS ACQUIRED Classifying Communicating Identifying patterns Inferring Organizing and analyzing data Predicting Alyson Mike East Helena Public Schools East Helena, MT RATING Teacher Prep 1 Student Set-Up 1 Concept Level 2 Clean Up 1 Easy Hard THE SCIENTIFIC METHOD Ask Questions Students are prompted to ask questions about the data as they prepare to construct their graphs and when they use the data to classify the biomes or ecosystems. Test the Hypothesis Students test their hypotheses as they analyze their graphs. Analyze the Results Students analyze the results of this laboratory activity when they answer Analysis questions 1 3. Draw Conclusions Students draw conclusions about the data presented in this laboratory activity when they answer the Conclusions questions. Communicate the Results Students communicate information as they formulate their hypotheses, construct their graphs, and answer the questions at the end of this activity. TIPS AND TRICKS Students can work individually or in pairs to complete this activity. Before students begin this activity, make sure they understand the difference between the terms ecosystem and biome. An ecosystem is all the living and nonliving factors that affect an organism. A biome is a major region that is characterized by its climate, soil type(s), and the dominant plants, animals, and other organisms that live there. A biome is made up of many individual ecosystems. Have students use their textbooks to review, if necessary, the definitions of the terms used in this activity. Some students may need assistance in plotting the data given in the table. If so, copy the transect grid onto an overhead transparency and use it to plot all of the data for San Francisco and at least one other Holt Environmental Science 71 Biomes

6 Factors that Influence Ecosystems continued city. Use different colors for the elevation and precipitation values. Remind students to include a key on their graphs that identifies the two sets of data. Challenge interested students to add several more cities (within the same latitude band) from other countries to the graphs and explain any variations. When students have finished the activity, lead a discussion that will enable them to conclude that rainfall and elevation are independent of latitude, while temperature is not. Holt Environmental Science 72 Biomes

7 Name Class Date Skills Practice Lab MATH/GRAPHING Factors That Influence Ecosystems Ecosystems are communities of plants, animals, and other organisms that live and interact with each other and with nonliving environmental factors. The nonliving factors, or conditions, include temperature, precipitation, altitude, and latitude, among others. These factors play an important role in determining what types of vegetation can live in an ecosystem. Latitude, for example, has a strong influence on an area s temperature, resulting in climates such as polar, tropical, and temperate. These climates determine different natural biomes that have characteristic species of plants. However, a careful look at a map reveals that ecosystems existing at the same latitude often have different climates. Why? In this laboratory activity, you will hypothesize how other nonliving factors influence the characteristics of ecosystems within the same latitude range. Then you will analyze and graph data from different areas of the United States to test your hypotheses. OBJECTIVES Hypothesize how precipitation and altitude affect the types of vegetation in an ecosystem. Graph and analyze ecosystem data to confirm or refute your hypotheses. MATERIALS colored pencils metric ruler Procedure 1. Form two hypotheses one that relates differences in ecosystem vegetation to rainfall and another that relates differences in ecosystem vegetation to altitude. Complete the following sentences to form your two hypotheses. Ecosystem distribution is related to precipitation; regions that receive large amounts of precipitation are wet and therefore. Hypotheses may vary. Most students will probably state that ecosystems that receive more precipitation will support more vegetation. Ecosystem distribution is related to altitude; regions at high elevations are cold and therefore. Hypotheses may vary. Most students will probably state that ecosystems at high altitudes will support little vegetation. Holt Environmental Science 73 Biomes

8 Name Class Date Look at the data table. The table lists major U.S. cities and weather stations between 36 north and 41 north latitude. It also lists the altitude, average annual precipitation, and ecosystem for each location. On the graph/grid on the following page, use one of your colored pencils to plot altitude for each location using the left-hand y-axis. Connect the data points. Plot the precipitation data in another color, using the right-hand y-axis, and connect the points. You may also find it useful to label the location names on the grid above your data points. Your completed line graph will help you interpret any relation among rainfall, altitude, and biome type. CHARACTERISTICS OF LOCATIONS ACROSS THE U.S. Distance from Altitude above Average Natural San Francisco sea level rainfall biome or (miles) (feet) (in./yr.) ecosystem San Francisco, CA redwood forest Sacramento, CA grassland Donner Pass, CA 200 7, coniferous forest Reno, NV 250 4,400 8 cool desert Salt Lake City, UT 650 4, cool desert Loveland Pass, CO , coniferous forest Denver, CO 950 5, short grass prairie Topeka, KS 1, tall grass prairie St. Louis, MO 1, broadleaf forest Cincinnati, OH 2, broadleaf forest Washington, D.C. 2, broadleaf forest Analysis 1. Identifying Patterns Which types of ecosystems occur in areas of high and low precipitation? Forests are more common in areas of high rainfall, and deserts are more common in areas of low-rainfall. Holt Environmental Science 74 Biomes

9 Name Class Date Annual rainfall (inches) 15,000 10,000 An Ecological Transect Across the United States Altitude (feet) 5,000 4,000 3,000 2,000 San Francisco 1,000 0 Donner 70 Loveland 60 Washington, D.C. 50 St. Louis Cincinnati 40 Topeka Salt Lake Reno Denver 10 Sacramento 0 0 San Francisco 500 1,000 1,500 2,000 2,500 Altitude Distance in miles from San Francisco Rainfall Holt Environmental Science 75 Biomes

10 Name Class Date 2. Examining Data Is there a trend in the amount of precipitation from Denver to San Francisco or from Denver to Washington, D.C.? If so, describe it. Yes, there is a trend from Denver to Washington, D.C. Rainfall increases toward the Atlantic Coast. Mountains interrupt the trend near San Francisco. 3. Analyzing Results How do mountain ranges affect precipitation? Give an example that supports your answer. Rainfall increases on the windward side, or the side facing the wind, of mountain ranges. Donner and Loveland passes are good examples of this effect. Locations on the leeward sides of mountains (the side not facing the wind) have lower rainfall. Conclusions 4. Evaluating Data Which is the more important factor in determining an area s ecosystem, the amount of precipitation or altitude? Is there an interaction between these two factors? Explain. Both factors are very important. Areas at higher elevations (Donner Pass) tend to have forest ecosystems unless there is not enough rainfall, in which case the area is a desert (Salt Lake City). 5. Defending Conclusions Does the data support or refute your hypotheses about the effects of precipitation and altitude on an ecosystem type? The data supports a hypothesis stating that precipitation nurtures ecosystems with lush vegetation. The data does not clearly support or refute a hypothesis stating that increasing altitude negatively affects vegetation. 6. Applying Conclusions Refer to the world biome map in your textbook. Examine the ecosystem patterns of the Eurasian continent. What can you infer about the distribution of rainfall in Eurasia? Eurasian ecosystems tend to have temperate deciduous forests near the east and west coasts of the continent. As one travels toward the interior, forests give way to grassland, and grassland gives way to desert. This implies that the amount of rainfall decreases as one moves from coastal regions toward interior areas. Holt Environmental Science 76 Biomes