Topic: ECOLOGY Unit Plan Sketch Part 1: Topic Content and Objectives Grade level: Middle school Larger topic Interactions within Ecosystem Communities Population Dynamics in Ecosystems I. Objectives for Student Learning Benchmarks for Science Literacy Food provides molecules that serve as fuel and building material for all organisms. Plants use the energy in light to make sugars out of carbon dioxide and water. This food can be used immediately for fuel or materials or it may be stored for later use. Organisms that eat plants break down the plant structures to produce the materials and energy they need to survive. Then they are consumed by other organisms. All organisms, including the human species, are part of and depend on two main interconnected global food webs. One includes microscopic ocean plants, the animals that feed on them, and finally the animals that feed on those animals. The other web includes land plants, the animals that feed on them, and so forth. The cycles continue indefinitely because organisms decompose after death to return food material to the environment. In all environments-freshwater, marine, forest, desert, grassland, mountain, and others-organisms with similar needs may compete with one another for resources, including food, space, water, air, and shelter. In any particular environment, the growth and survival of organisms depend on the physical conditions. Two types of organisms may interact with one another in several ways: They may be in a producer/consumer, predator/prey, or parasite/host relationship. Or one organism may scavenge or decompose another. Relationships may be competitive or mutually beneficial. Some species have become so adapted to each other that neither could survive without the other. National Science Education Standards LIFE SCIENCE CONTENT STANDARD C: As a result of their activities in grades 5-8, all students should develop understanding of Populations and ecosystems Page 1 of 8
Students understand ecosystems and the interactions between organisms and environments well enough by this stage to introduce ideas about nutrition and energy flow, although some students might be confused by charts and flow diagrams. If asked about common ecological concepts, such as community and competition between organisms, teachers are likely to hear responses based on everyday experiences rather than scientific explanations. Teachers should use the students' understanding as a basis to develop the scientific understanding. Michigan Objectives 1. Describe common patterns of relationships among populations. Using 2. Describe how organisms acquire energy directly or indirectly from sunlight. Using 3. Predict the effects of changes in one population in a food web on other populations. Using 4. Describe the likely succession of an ecosystem over time. Using 5. Generate scientific questions about the world based on observations. Constructing 6. Use tools and equipment appropriate to scientific investigations. Constructing 7. Develop an awareness of and sensitivity to the natural world. Reflecting Your synthesized Objectives Describe how organisms obtain energy for life. Explain how organisms in a community interact. Predict the evolution of an ecosystem over time. Identify and analyze the characteristics of different biomes of the Earth and the interactions of organisms within them. II. School Science Approach Facts Vocabulary Words 1. Food chain - a diagram illustrating the feeding relationships of organisms, shows how energy and matter are transferred through the environment 2. Food web a pattern of interconnected food chains 3. Ecosystem - the living and non-living things interacting in the environment in a certain place 4. Population a group of organisms of the same species Page 2 of 8
5. Community the plant and animal populations that live together and interact in an ecosystem 6. Producer - an organism that makes its own food; plants are producers 7. Consumer - an organism that needs to eat other organisms for its food 8. Herbivore - an organism that eats primarily plants 9. Carnivore - an organism that eats primarily other animals 10. Omnivore an organism that eats both plants and animals 11. Decomposers organisms that break down previously living organisms and their waste 12. Prey - an organism that serves as food to another organism 13. Predator - an organism that seeks out other organisms for food 14. Symbiosis a close relationship between different species 15. Mutualism a symbiotic relationship in which both species benefit 16. Commensalism a symbiotic relationship in which one organism benefits and the other is not affected 17. Parasitism a symbiotic relationship in which one organism benefits but the other is harmed 18. Biomes large geographic areas that have similar climates and ecosystems 19. Biotic a living thing or something that once was living 20. Abiotic a nonliving thing 21. Succession the normal, gradual changes that occur to the species that live in an area Diagrams or standard representations Page 3 of 8
Formulas or problem-solving skills III. Reform Science Approach Knowledge: Experiences, Patterns, and Explanations Observations or experiences (examples, phenomena, data) Lichens growing on fences or trees that live within a fungus. Clown fish swim along the tentacles of sea anemones. Roundworms living within the intestine of a dog. Draw or see diagrams of food chains within different ecosystems. Make a food chain that includes yourself and trace it back to the original source of energy. Data is collected from a picture of an ecosystem. A herd of 15 cows occupy a grassland, as well as 12 goats, and two humans standing between the two groups. Patterns (laws, generalizations, graphs, tables, categories) Organisms live together and share resources in a variety of ways. They may both benefit from an association, only one may benefit while the other is unaffected, or one may benefit while hurting the other. Organisms in an ecosystem are part of a food web that demonstrates energy transfer among a community. Energy is lost in the form of heat as you move along a food chain. Different groups of the same species are called populations. There is a population of 15 cows. The populations interact with each other in the patterns listed above. Explanations (models, theories) Symbiotic relationships. Energy transfer relationships. Food Chains/Webs Energy Pyramid Populations interacting with each other within an ecosystem form a community. Page 4 of 8
On a map of the world we see distributions of where there are more varieties of species. As you move toward the equator, the variety of species increases. Biodiversity is greater where the climate is warmer and wetter. We see a diagram of a backyard that has changed over time. It once had grass and now has many tall trees. There are many different environments around the world. We live with many trees but places like Arizona have very little trees or grass. Brainstorm and describe areas of the world that are different in terms of physical appearance. Grass that is uncut gets longer and creates a meadow. Seeds may be brought in by new animals to the area or wind and small shrubs and trees may begin to grow. The trees grow larger and different animals enter the area that are more adapt to living in this type of environment. A forest fire could occur and burn everything to the ground. Climatic factors such as temperature and precipitation affect the types of ecosystems around the world. Application: Model-based Reasoning Inquiry: Finding and Explaining Patterns in Experience The stages of Ecological Succession. Large geographic areas that have similar climates and ecosystems are called Biomes. III. Big Ideas Every environment is composed of living and nonliving parts, and in every environment, the living and nonliving parts interact with each other in a variety of ways. Ecology is the scientific study of these interactions. There are countless relationships that affect the overall success of each respective environmental community; nothing works independently. An ecosystem is a group of living or once living (biotic) and nonliving (abiotic) parts within an environment and all the connections between those parts. Sometimes the connections occur between living components (food chain), sometimes between nonliving components (erosion) and sometimes between living and nonliving components (photosynthesis). Page 5 of 8
The living parts of an ecosystem include animals, plants, fungi and microorganisms. Each of these living things of the same species is called a population. A community consists of the plant and animal populations best suited to the nonliving components of the area. The nonliving, or physical components of an ecosystem include the sun's energy, water, air, rock and the land forms made of rock. Soil is composed of living (plant and animal detritus) and nonliving (rock particles) components. Within these communities exists many relationships among organisms. Mutualism, commensalism, and parasitism are all types of symbiotic relationships among organisms. The variety of life or number of populations in an ecosystem is a measure of the biodiversity within that ecosystem. Biodiversity tends to increase as you move toward the equator because the climate is wetter and hotter. The earth is comprised of many different examples of ecosystems, including grasslands and tropical rain forests. A large geographic region that has similar climates and ecosystems is called a biome. At a simple level, we can make food chains that show the energy transfer along one chain of organisms. However, the connections in each environment are countless. For example, a bear eats trout for energy but also eats berries for energy. The berries may also be eaten by a squirrel. These multiple chains create a more complex food web. The berry plant is a producer because it makes its own energy. The bear is a consumer because it cannot make its own energy. It has to eat other organisms to obtain energy. An ecosystem is the delicate state of balance between living and nonliving things in a particular environment. If a part of an ecosystem is removed or altered, the existing harmony will be offset and the entire system will go through a change, large or small, positive or negative. Succession refers to the normal, gradual changes that occur in the types of species that live in an area. If you were to allow grass in a yard to grow without disruption, soon it would look like a meadow. Later, larger plants would grow from seeds brought into the area by animals or wind. Trees may begin to sprout. Understanding the interconnectedness of things in an ecosystem provides a basis for respecting the significance of each of the different parts of the surrounding environment. Part 2. Assessment I. Preassessment Using the following organisms, make a diagram or explain how the energy from the sun is reaches you so that you can live. Minnow Small Insect Trout You Page 6 of 8
II. Embedded Assessment Objective 1: Describe how organisms obtain energy for life. Objective 2: Describe common patterns of relationships among populations. Objective 3: Predict the effects of changes in one population in a food web on other populations. Objective 4: Describe the likely succession of an ecosystem over time. Embedded assessment: Ask the students at a basic level how they believe they get the energy to move around and play sports, etc. Embedded assessment: Have the students brainstorm some interactions among animals where at least one benefits in some way. Embedded assessment: Kind of dreary but ask the students for examples of animals they may have or have seen at a farm. Ask them what their food source is and then predict what would happen if neglected to give them their food source. Embedded assessment: Have the students go outside and see if they can predict what happens to the grass in the field if it was left alone. Also ask why that area is just small grass now instead of an area right next to it with a lot of trees. III. Formal Assessment Objective 1: Describe how organisms obtain energy for life. Formal assessment: Combine the following food chains into one food web. Algae and floating plants crayfish carnivorous fish raccoons Algae and floating plants minnows carnivorous fish Algae and floating plants minnows raccoons Algae and floating plants minnows ducks Objective 2: Describe common patterns of relationships among populations. Objective 3: Identify and analyze the characteristics of different biomes of the Earth and the interactions of organisms within them. Objective 4: Describe the likely succession of an ecosystem over time. Formal assessment: Bees and apple trees are beneficial to each other because A. bees obtain pollen and nectar from flowers, and flowers are protected by bees. B. bees obtain pollen and nectar from flowers, and flowers are pollinated by bees. C. bees obtain water from flowers, and flowers are protected by bees. D. bees obtain water from flowers, and flowers are pollinated by bees. Formal assessment: The students are put into biome groups and work on a project that includes creating food chains and webs and the relationships of organisms within their biome. They also describe the abiotic factors of their biome. They make a power point and poster presentation for the class. Formal assessment: You play baseball in a field at the park where the grass is mowed all summer. What would happen to your baseball diamond if no one mowed the grass at all? What kind of Page 7 of 8
succession would occur? Part 3. Activity Cycle Objective: Describe how organisms acquire energy directly or indirectly from sunlight. Using (This particular focus is understanding an energy pyramid at a very basic level) Stage Establish a Problem Model Coach Fade Activity cycle Activity How much energy gets transferred through a food chain? Show a simple four-step food chain and model how you would make that into a food pyramid. The main point is that the bottom should always be a producer because they have the most energy available and also have larger populations. As you move up the food chain, energy is lost in the form of heat so less is available to be transferred. Therefore, there are less consumers as you move up the food chain because less energy is available. Give the students an Antarctic food chain example (five or six steps) and have them create their own energy pyramid. Also have them write out which populations are the smallest and which are the largest. Circle around the room to give hints or help to those who are stuck. Give an if-then assignment that contains a few (if the producer in this energy pyramid were to become more scarce, then ) Page 8 of 8