Summary
Students discover what ecosystems are by exploring the relationships between him/herself, other living things, and the student's environment. Students create and study miniature ecosystems by building a terraqua column - a 2 story soda bottle tower with soil and plants on the top and a water source on the bottom. The terraqua columns will be used throughout the ecology unit for practice with water and soil quality monitoring and with making and recording observations. Later in the unit students can conduct independent investigations with their terraqua columns.
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Objectives
Can define ecosystem and ecology Vocabulary Ecosystem |
Terraqua Column from Bottle Biology
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Time
30 min ecosystem lesson and discussion
20 min build terraqua column frame
20 min add soil, water, and seeds
* I recommend building the terraqua column frame on one day then adding the soil, water, and seeds the following day.
Grouping
2-3 students
Materials
For each group:
For 2-3 groups to share:
For whole class to share:
Optional:
Setting
Classroom
Teacher Background
Understanding ecosystems is the basis for all of the study of ecology. Students are introduced to the idea of an ecosystem by examining his or her interactions with other living things and the environment. The terraqua column that students build becomes the foundation for the following weeks of exploration of water, soil, living things, and the environment.
Bottle Biology contains a wealth of information about the terraqua column project and further directions to explore. Definitely check out the Bottle Basics section to learn about working with soda bottles and also the Terra Column section for everything you wanted to know about building, maintaining, and studying terraqua columns. This site has a much more detailed step-by-step building guide complete with diagrams and troubleshooting.
Student Prerequisites
none
Getting Ready
Ecosystem lesson and discussion
Terraqua column construction
Filling the Terraqua Column
Assessment Create an ecosystem diagram for an animal of your choice. Be sure to include interactions between your animal and other organisms AND between your animal and its environment. Going Further
Sources
Bottle Biology contains everything you wanted to know about terraqua columns.
The Learner website has wonderful pictures of terraqua columns in progress as well as many extensions to try.
Standards
Grade Six
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment.
Summary
Students conduct 3 tests of water quality in the classroom that can then be applied to their terraqua columns and to the outdoors: pH, dissolved oxygen, and temperature. They make comparisons between different types of water and draw conclusions about how "healthy"? each water source is for fish and other organisms. Through this process, students practice their observational and data analysis skills. Water quality monitoring data is routinely used in the "real world" to determine the effects of habitat restoration, development, pollution, and wastewater treatment. It is often the initial step in describing the health of an ecosystem. There are hundreds of ways to extend this simple activity and make connections to the real world - from monitoring water quality in a local creek to making comparisons between different bodies of water in your area.
Objectives
Can make comparisons between different water samples.
Can conduct tests of water quality.
Can interpret tests of water quality.
Can record data in a science lab notebook.
Vocabulary
pH
acid
base
dissolved oxygen
Time 5 min introduction to water quality 20-25 min conduct water quality tests 20-30 min discussion of class results Grouping 2-3 students Materials For whole class to share:
Teacher Background
This activity, like the Soil Analysis activity are fabulous springboards for future independent investigations and real world connections. Water quality is one of the first things analyzed by environmentalists, government agencies, aquarium owners, gardeners, and business men and women when asked about the health of an ecosystem. It is a question you can ask about the water that comes out of your tap and that goes down the drain. This lesson gives students experience with 3 very simple water quality measures although there are many many more tests available to try (salinity, phosphates, chlorine, nitrates, fecal coliform, and others).
The first test is temperature which simply measures how hot or cold something is. Water temperature significantly affects the type of life that can survive. High temperatures reduce the amount of dissolved oxygen. The rate of photosynthesis gradually increases as water temperature rises, although beyond 32 degrees Celcius, the rate of photosynthesis falls again. Similarly the metabolic rate of plankton, insects, and other water life varies according to the temperature of the water. Human impacts that can affect water temperature include thermal pollution from industry, deforestation resulting in fewer trees to shade water, and soil erosion adds sediments to the water increasing the absorption of solar heat.
The second test measures pH. pH is a measure of the hydrogen ion concentration in liquids and other substances. Acids such as vinegar and lemon juice have high concentrations of hydrogen ions and register below 7 on the pH scale. Bases such as soap and milk have low concentrations of hydrogen ions and register above 7 on the pH scale. Pure deionized water has a neutral value of 7. Pure rainwater has a pH closer to 5.6 although natural freshwater sources such as creeks, ponds, and lakes fall between 6.5 and 8.5. Some water sources such as bogs (with a pH as low as 4.2) have naturally low pH. Human impacts such as acid rain, pollution, and chemical spills can affect pH values.
The final test, dissolved oxygen, measures the presence of oxygen in the water, an essential ingredient for animal life. Dissolved oxygen is measured in parts per million or ppm. Although some organisms can survive at very low dissolved oxygen levels, 7-14 ppm is generally considered healthy for most fish and other aquatic life. Levels of 3-5 ppm are considered stressful and 0 is termed anoxic. Oxygen is introduced into water from the atmosphere (running water and wind increases the amount of oxygen) and from aquatic plants. A reduction in dissolved oxygen often is the result of increased temperature, changes in stream flow such as damming a river, the build up of organic wastes from pesticides and fertilizers, and eutrophication (if too much algae and plant life grows, as the plants die the bacteria population explodes, virtually eliminating all dissolved oxygen from the area).
Student Prerequisites
none
Getting Ready
Prepare 3 stations around the classroom with the materials needed to conduct that test and a printout of the student instructions (downloadable below).
Lesson Plan
Assessment
Sources
Distributors of water quality test kits:
This activity was adapted from Monitoring Creek Health a 6-8th grade curriculum written by the Point Reyes National Seashore Association.
Save the Bay also developed a superb curriculum which includes many ideas for mapping, monitoring, and restoring local watersheds. This lesson is in many ways modeled after Save the Bay’s lesson plan “Keeping an Eye on Our Creeks”.
Kids in Creeks is a curriculum guide produced by the Watershed Project and is available to teachers who take their superb workshops. They provide extensive resources for teachers interested in adopting a local creek. Included in their curriculum are many water quality monitoring activites, including conducting an insect survey and a plant life survey as indicators of creek health.
North Carolina State University has an excellent set of additional activities to further investigate the effects of water quality factors.
Standards
Grade 6
Ecology (Life Science)
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Grade 8
Reactions
5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept:
e. Students know how to determine whether a solution is acidic, basic, or neutral.
All grades
Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations.
Summary
Students conduct 4 tests of soil quality in the classroom that can then be applied to their terraqua columns and to the outdoors: visual observation, soil separation, pH, and Tullgren Funnel (to isolate living things in the soil). They make comparisons between 2 different types of soil and draw conclusions about how "healthy"? each soil is. Through this process, students discover the major "ingredients"? of soil: clay, silt, sand, organic material, water, air, living things, and minerals. By recording information in their science journals, they learn how to keep good notes and share the information with others in the class during a concluding class discussion about what "healthy"? soil might look like and why.
Objectives
Can describe the major components of soil.
Can make comparisons between different soils.
Can conduct tests of soil quality.
Can interpret tests of soil quality.
Can record data in a science lab notebook.
Vocabulary
loam
clay
silt
sand
organic material
Tullgren Funnel
pH
acid
base
Time
Day 1:
Optional: 5 min discuss soil observation homework from last night
10 min observe samples of different soil ingredients
30-40 min conduct soil quality tests
Day 2 (several days later):
15 min complete observations of Tullgren Funnel and soil separation tests
30 min discuss results and draw conclusions about "healthy"? versus "unhealthy"? soil
* Since the Tullgren Funnel and soil separation tests take several days, it is recommended to start Day 1 on a Friday and complete Day 2 on a Monday. *
Grouping
2-3 students
Materials
For each group of students:
• 4 petri dishes
• 2 funnels (card stock paper rolled and taped into a funnel shape and cut to 4-6 inches tall may be substituted)
• 2 funnel holders to hold funnels upright above a Petri dish (card stock paper rolled into a tube works well or you can eliminate the Petri dish as well by using a cup that the body of the funnel rests in as long as the bottom tip of the funnel does not touch the bottom of the cup)
• 2 square of cheesecloth
• 2 strips pH paper
• 2 white paper towels
• 2 clear 15 ml tubes with lids, glass or plastic
For whole class to share:
• Clay in ziplock bag
• Sand in ziplock bag
• Silt in ziplock bag
• Compost in ziplock bag
• 8 large plastic cups
• 8 plastic spoons
• 2 graduated cylinders
• 2 tablespoons
• 2 rulers
• 2 different types of soil (The more different the texture, composition, and organism content of the 2 soils, the better. For example, try soil from the school yard vs. store-bought potting soil, a clay soil vs. a sandy soil, or rich garden soil vs. soil from an abandoned lot.)
• 3-4 bare light blubs hung or mounted approximately 1 foot from the table top (desk lamps work well)
• 1 small jar alum (available at supermarkets for pickling)
• 2 magnifying glasses
• 1 package removable dot labels or rolls of masking tape
Setting
classroom
Teacher Background
In an ecosystem, the soil and water form the foundation of the surrounding environment. Environmental impacts such as deforestation, the introduction of invasive species, climate change, acid rain and others all have profound implications on the soil and water in the area. Many changes can be readily detected and tracked by very simple tests that students can conduct with very simple materials. This lesson and the parallel water quality analysis lesson are opportunities to teach students the observational and analytical skills needed to apply these tests to real ecosystems in the real world.
The first test is a simple soil observation using all your senses. This allows students to practice observation and recording skills and helps kids notice that all soil is not the same.
The second test is a soil separation test to determine the relative proportion of clay, silt, sand and organic material. It draws on the principle of a density column where the largest, most dense particles (in this case sand) settle first. During the introduction of this portion of the activity, you can discuss density or not, depending on the background of your students. Students generally intuitively understand that in water, big heavy things will sink first. Clay soils tend to be sticky when wet and will hold together in a ball. When dry, clay soils harden to an almost rock-like density, holding very little air, thus making it difficult for critters to survive. Sandy soils tend to drain water rapidly. From a gardener's perspective, the ideal soil is a balanced mixture of sand, silt and clay with lots of air, water and organic material mixed in. The alum used during this test helps separate the particles of soil. Alum is relatively non-toxic but students should be warned not to put it in their mouths and should wash their hands after this station (and at the end of the period).
The third test measures the pH of the soil. pH is a measure of the chemical and mineral content of soil. Most plants prefer soil that is slightly acidic (between 5.5-7). However, some plants require very acidic soils (less than 4.5) to survive (such as blueberries and azaleas). Impurities and pollutants such as detergents, acid rain, and trash will alter the pH of soil. Major human disruption from mining, logging, and construction also changes the pH of soil by allowing the more neutral topsoil to erode, exposing the subsoil layers which tend to be more acidic.
The final test uses a Tullgren funnel (sometimes called a Berlese separator) to isolate bugs, worms and other critters from the soil. The basic principle is that the soil is placed in a funnel beneath a heat source. The mites, worms, and insects in the soil move downward through the soil to escape the heat and eventually fall out the bottom of the funnel into water. It can be absolutely fascinating for students to discover that soil is alive with critters large and small. Because it takes some time for the critters to fall through the funnel, (between 2-4 days) it is often ideal to allow the test to continue over a weekend. But make sure that there is enough water is the Petri dishes or the cup so that the water below the funnel does not dry out. For additional information and ideas about the Tullgren Funnel, see: The Open Door Website. How do you identify the critters? Great question and as of now, I have no idea. I have not found a good field guide which can be used to identify soil critters. If you find something, let us know!
Additional tests may be used or substituted for the 4 included here. For instance, you can measure the water-holding capacity of soil by adding fixed quantities of water (10 mls at a time for instance) to fixed quantities of dry soil in a funnel until water begins to drain out of the bottom. Water will continue to drain out the bottom until the soil reaches a steady state. Take the amount of water you added initially and subtract the amount of water that drained out and you have your water-holding capacity. This measurement relates closely to the composition of the soil. The more clay, the more water the soil holds. The more sand and gravel, the less water the soil holds.
What makes up healthy soil? In general, a balance of all soil ingredients with few pollutants and lots of organic material and living things makes healthy soil. Soil that completely lacks organic material or that is far outside the normal pH range is generally considered unhealthy. Soil that is completely dry cannot support life. A large number of soil critters is often a good indicator of healthy soil. However, this depends dramatically on the location and use of the soil. Soil in a garden will be different from forest soil which will be different from creek soil. Therefore, in the discussion of what makes healthy soil, expect and encourage differences in opinion.
Student Prerequisites
It is recommended that students are familiar with pH - both understanding what pH is a measure of relative to household items and how to measure it using indicators. The previous lesson 2. Water Analysis provides a sufficient introduction to those ideas.
Optional: Comparing Soil Homework - This assignment asks students to observe and compare 2 samples of soil, one from home, one from school, and to devise original tests to look for differences between the soils.
Getting Ready
Lesson Plan
Assessment
Sources
Terrarium Habitats a GEMS guide by the Lawrence Hall of Science includes a great soil observation activity, including the soil separation test and Tullgren Funnel test.
The Open Door Website describes the Tullgren Funnel test with pictures and additional details.
Standards
Grade 6
Shaping Earth's Surface
2. Topography is reshaped by the weathering of rock and soil and by the transportation
and deposition of sediment.
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Grade 8
Reactions
5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept:
e. Students know how to determine whether a solution is acidic, basic, or neutral.
All grades
Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations.
Summary
Delve into a micro-habitat that is the size of a drop of water. This lesson allows students to explore the plankton (organisms that drift with the currents) that exist in a drop of pond, lake, or bay water. A microscope is required to view most organisms although some are observable with a hand lens. If possible, this is a fantastic opportunity for students to collect the pond water themselves using pantyhose and a small bottle. If you are pursuing a restoration project, collecting water might be an excellent excuse for an initial visit (as long as the creek/body of water has regions of relative calm where algae can grow on the rocks). Plans for both an initial creek visit activity and a classroom investigation of the water sample are included in this lesson plan. If it is not possible to bring students to the creek or pond, then you can collect the sample ahead of time and skip the creek visit and sense of place activity.
Objectives
Creek visit:
Develop a sense of place.
Pond water investigation:
Can define organism, habitat and microhabitat.
Can identify organisms using a key or field guide.
Can use a microscope.
Vocabulary
Plankton
Organism
Habitat
Microhabitat
Microscope
Objective lens
Stage
Eyepiece
Arm
Focus (fine and coarse)
Time
Creek visit:
5 min introduction
30 min at the creek
traveling time to creek and back varies
Pond water investigation:
10 min introduction to the proper use and handling of microscopes and slide preparation
30-40 min exploration
10 min wrap up discussion
Grouping
2 students
Materials
Creek visit:
• Small jar or bottle with a sealable lid.
• Optional: 1-2 plankton nets (available for $75 from Science Kit and Boreal Labs OR make your own with panty hose, string, duct tape, a wire coat hanger, and a film canister at The Plankton Net. Plankton nets will greatly increase the number of organisms that you collect although you can simply squeeze the water from water plants, dead leaves, and pond scum into a container.
Pond Water investigation:
For each pair of students:
For whole class to share:
Setting
Creek visit: nearby creek, pond, lake, bay or other body of water. Plankton are most commonly observed and collects from water that is fairly still and that has a growth of algae either on the surface or on the rocks and detritus near the bank.
Pond water investigation: classroom
Teacher Background
In order to introduce students to the concept of habitats and ecosystems it is often interesting to look at the microhabitats that can be observed only when you look very closely. Plankton which live in ponds, lakes, and other bodies of water form the foundation of the entire aquatic food chain. Students are fascinated by the complexity and diversity of life that can be observed in a single drop of water.
If you need to collect plankton yourself, it is best to observe the samples that day or no longer than 1-2 days later. Many plankton are fragile and tend not to survive long outside their natural habitat, particularly at the population density obtained after using a plankton net. However, some plankton can be maintained in the classroom for several days or even weeks under the right conditions – adequate dissolved oxygen and access to a food source. In fact, an interesting extension would be to monitor the types of organisms observed by the class over time as species die out and other increase in numbers.
Student Prerequisites
Experience with microscopes allows students to jump into the classroom portion of the activity more quickly but is not necessary.
Getting Ready Creek visit:
Lesson Plan
Creek visit:
Pond water investigation:
Assessment
Research one of the organisms you observed. What does your organism eat? Where is it found? What does it need to survive? Describe its life cycle.
Going Further
Sources
This lesson was adapted and inspired by the Pond Water lesson available at Science NetLinks. This site has student worksheets and other excellent resources.
Instructions for building plankton nets can be found at The Plankton Net and Bigelow Laboratory.
The Plankton Net has superb scientific information, photographs, and resources about plankton ecology and marine science in general.
Miscape has a superb cartoon drawing identification key for common pond water organisms as well as information about collecting and maintaining pond water organisms in the classroom.
A superb pond life site can be found at the Sparsholt Schools' Centre. Their "virtual pond dip" is an excellent pond insect identification guide.
The book Pond Life: Revised and Updated (a Golden Guide from St. Martin's Press) by George K Reid is an excellent resource with an identification key for pond life ranging from the microscopic to common birds and mammals.
A great source of information about microscopes and their parts may be found at Microscope.org.
If you do not have compound microscopes (or any microscopes at all) many pond water organisms such as coepepods, ostracods, algae, and insect larvae may be observed with a hand lens. If you have more time or want to integrate an optics project into your pond water investigation, you can build your own microscope out of simple everyday materials. A super microscope plan can be found at the Fun Science Gallery.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism
through food webs.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Grade 7
Cell Biology
1. All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through a microscope.
All grades
Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
b. Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.
Summary
Students review the concepts of food chains and the roles of organisms in a food chain through a simple card sorting activity. Cards representing different individuals in a California ecosystem are first sorted by herbivore, carnivore, dentrivore, and omnivore, then are reordered to create several food chains. In addition, students begin to understand the idea of a food pyramid – since all living things use energy to move, reproduce, respond to the environment and grow, less energy is available to pass on at each link of the food chain.
Objectives
Can define and construct a food chain.
Can identify the role of organisms within a food chain.
Can trace the path of energy through a food chain.
Can build a food pyramid and explain how it functions in terms of energy transfer at each level.
Vocabulary
Food chain
Produce
Consumer
Herbivore
Carnivore
Dentritivore (or Decomposer)
Omnivore
Food pyramid
Time
45-50 minutes
Grouping
none
Materials
Setting
classroom
Teacher Background
This activity teaches students 2 things, 1) it reviews the concept of food chains and the major roles of organisms with a food chain and 2) it illustrates the concept of a food pyramid and the transfer of energy from one organism to the next through the food chain. Most students should be familiar with the concept of a food chain and food pyramid from elementary school science, but it is worth at least one class period to thoroughly review these concepts in preparation for more in depth investigations of food webs, ecosystems, and population change.
Food chains are the most simple arrangement of who eats whom assuming that each organism only eats one thing. Of course, in real life this is not the case. Still, it is useful to consider food webs as tangled food chains; therefore, understanding food chains is an essential prerequisite.
The roles that organisms play within a food chain are very well defined. Producers make their own food through photosynthesis. Consumers eat producers or other consumers and may be divided into 4 major categories: herbivores which eat producers, carnivores which eat herbivores or other carnivores, dentritivores (also called decomposers) which recycle the energy from dead organisms to make nutrients available for producers, and omnivores which eat producers and consumers.
Although it is tempting to emphasize that every food chain begins with the sun as the source of energy on which photosynthesis depends, in fact, not all food chains begin with the sun. Organisms near hydrothermal vents at the bottom of the ocean depend on sulfur as the initial energy source. These bacteria use a process called chemosynthesis, taking hydrogen sulfide and oxidizing it, thereby releasing energy. This is typically far more advanced than middle school classrooms although you may wish to allude to the existence of food chains that do not rely on the sun as the initial energy source. For further information, see RESA has a superb website about life at hydrothermal vents.
The concept of a food pyramid adds a level of complexity to the concept of food chains. A producer uses energy from sunlight to grow, reproduce, and survive. Only a small fraction of that energy can be used by a herbivore that eats that producer. Similarly, that herbivore needs to use energy to grow, reproduce, and survive. A carnivore that eats that herbivore does get some energy from that herbivore but only a small percentage. Another way to think of it is to consider how many seeds a plant produces in its lifetime, how many seeds a chicken consumes in its lifetime, and how many chickens a human will consume in its lifetime. Clearly, energy is used and lost at each level of the food chain. Using a food pyramid to illustrate this concept helps students see this visually.
Student Prerequisites
None.
Getting Ready
Lesson Plan
At this point, introduce the idea of producers as plants, or more scientifically, as organisms that make their own food through photosynthesis. Introduce the idea of consumers as animals, or more scientifically, as organisms that eat producers or other consumers.
Introduce the vocabulary words herbivore, carnivore, omnivore, and dentritivore at this point and give the formal definitions.
Assessment
Sources
The idea for the food chain card game came from Project WILD’s book Alaska Ecology available for purchase online for $22.
Debbie Breeding’s activity Food Chains and Webs provided the information and pictures for the food chain cards. The illustrations on the activity pages are by Paula McKenzie, copied from Mountains to the Sea- A Visitor's Guide to the Santa Monica Mountains and Seashore.
Another web resource that provides a similar activity is available from the British Ecological Society. Some of the illustrations on the activity pages are copied from the food chain cards available on their site.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism
through food webs.
b. Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.
c. Students know populations of organisms can be categorized by the functions they serve in an ecosystem.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Summary
In this 2-3 day activity, students choose an organism and research its life cycle, food chain, and habitat. The student research is assembled in 2 ways. First, the classroom is cleared of tables and chairs while students use their organisms to create a food web stretching the length and width of the classroom. Second, the pages are assembled to create a field guide for your local area or for a field trip into a state or national park nearby. I found this to be an extremely effective way to get students interested and excited about an upcoming field trip. I choose insects, birds, fish, mammals, amphibians, and reptiles commonly sighted at Point Reyes National Seashore for students to research a week before the scheduled field trip. On the field trip itself, students were very excited to spot their animals and the student who did the research would usually come forward to tell his or her classmates all about their organism.
Objectives
Can conduct independent research.
Can use a field guide to research an organism’s habitat, diet and life cycle.
Can identify insect, animal and plant species in the field.
Can define habitat.
Can identify the parts of a habitat and give examples.
Can predict how habitat change might affect the organisms living within it.
Vocabulary
Habitat
Food web
Endangered species
Threatened species
Time
10-20 min introduce activity
45-60 min complete research (some may be assigned for homework)
45-55 min construct food web on classroom floor
Grouping
Individual
Materials
For organism research
For food web activity
Setting
Classroom, library or computer lab.
Teacher Background
This is a superb activity if you are planning an ecology based field trip or restoration project in an area where local wildlife can be observed. The student research makes students immensely interested and excited about the organisms they might observe in the field. In many ways, this was the highlight of the ecology unit in my students eyes.
The general idea is that students create a field guide to use in the outdoors. Through the process, students gain experience using published field guides, learn about habitats, food webs, and discover threatened/endangered species in their local environment.
I created my list of organisms with a trip to Point Reyes National Seashore in mind. Thus, the creatures represent riparian and coastal California chaparral habitats. If you are planning a trip, the park you plan to visit will usually have a list of wildlife that you can use. I strongly recommend creating your list of organisms to represent local habitats or habitats you plan to visit. If you have too many students for just consumers, consider increasing the number of organisms by including producers as well.
The concluding activity in which a food web is constructed across the classroom floor is fun but often chaotic. I found that 20-30 students can create a complex, representative food web. Therefore it is recommended that you use one class worth of students to assemble a large food web, put away those organisms and start over with the next group of students. Some organisms, such as top carnivores and decomposers are more rare so you can keep those pages available to add to the following class’s food web if you want.
Crowd control in this activity can be quite a challenge if you have an unruly class. In this case, you may want to consider putting the food web together on the board with students still in their seats.
Student Prerequisites
Knowledge of food chains and organisms’ roles within a food chain. It is helpful if students know what habitats are and how to use a field guide although this can be taught during the lesson.
Getting Ready
For organism research
For food web activity
Lesson Plan
For organism research
For food web activity:
Assessment
Going Further
Sources
This activity was adapted from Monitoring Creek Health a 6-8th grade curriculum written by the Point Reyes National Seashore Association. Their lesson focued on the insects found in aquatic, creek habitats. I used resources from Point Reyes National Seashore to supplement the list of organisms to research with birds, mammals, reptiles, amphibians, and other species that are commonly encountered in the park. The Point Reyes website has great descriptions of the plant and animal life in the park.
The book Life on the Edge – A guide to California’s Endangered Natural Resources by Biosystem Books is a superb resource for identifying and researching endangered and threatened species.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
b. Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.
c. Students know populations of organisms can be categorized by the functions they serve in an ecosystem.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Summary
In this activity, students finally get to apply their skills of soil analysis and observation to a 1 meter by 1 meter area of the schoolyard, restoration site, or creek bank. Teams of students get down and dirty exploring the soil, vegetation, and insect life in their microhabitat. Students practice using the soil analysis tools they learned previously and also practice using field guides to identify plants and insects. Upon returning to the classroom, they compare their results with other groups to see the differences and similarities between their microhabitats. This is a superb activity to use before and after a habitat restoration project or simply to track changes in a habitat throughout the year. I used this investigation to introduce the idea of native vs. non-native species and to begin a debate about invasive species. My students really “got it” when they examined our adopted restoration area and discovered that there was a monoculture of invasive, non-native English ivy all across our site. They visited our adopted site 3-4 times throughout the year pulling ivy and planting native plants. When all was said and done, they repeated this investigation in the spring to discover exactly the magnitude of the change they made on the environment – and to find that the native plants recruited a wider variety of insects than they had seen at that site in the fall.
Objectives
Can conduct tests of soil quality. Can interpret tests of soil quality. Can identify insect, animal and plant species in the field. Can define habitat and microhabitat. Can record and interpret data in a science lab notebook. Can apply classroom knowledge to real world data.
Vocabulary
Microhabitat
Invasive species
Native species
Non-native species
Time
For habitat survey:
40-50 minutes at the creek
traveling time varies
For setting up the soil analysis tests in the classroom:
10-15 minutes to set up soil separation and Tullgren funnel tests
10 minutes to identify plants and insects
A day later, analyze the results and have a class discussion:
10 minutes to interpret soil separation and Tullgren funnel tests
10 minutes to compare results with another group
20-30 minutes group discussion
Grouping
2-4 students
Materials
For habitat survey, each group of students needs: (I assembled all the materials into several shoebox-sized plastic containers to become our class set of “creek kits”)
Teacher Background
Most of us are familiar with the threats to ecosystems such as rainforests, wetlands, and oceans. Naturally, anything that is a concern on a large scale such as global warming or clear cutting should be studied and researched. However, many organisms do not use an entire ecosystem. Most live in a relatively tiny portion of a larger ecosystem, a microhabitat. In fact many organisms spend their entire lives within a 1 meter square area. It is essential to recognize that organisms do not need an entire ecosystem to be damaged to find that their little microhabitat has been destroyed.
I believe that science skills such as water quality monitoring or soil analysis are of little interest to students unless these skills are applied in the real world to real problems that may not have ready-made solutions. Therefore, after teaching them how to make observations and analyze soil samples in the classroom, I take my students to apply these skills to a real world problem – invasive English ivy that has taken over the bank of a nearby creek. This problem gives students an opportunity to carefully monitor a microhabitat, recognize that ecology happens on a small scale (as well as a larger scale) that an individual person can make a difference on, and create a plan of action to help their microhabitat.
Invasive species are organisms that not only are non-native, but which take over a habitat and out-compete the native organisms. There are many examples of invasive species. Each has a story about where the invasive species came from, how it got to the area, and what adaptations allow this species to out-compete the native species that typically occupy that niche of the food web. English ivy is just one example. It was brought over to America by Europeans who decorated their houses and gardens with this robust, fast-growing vine. In Europe, ivy does not out-compete the plants in the local ecosystems, however, in California, ivy will quickly invade and cover large areas to the exclusion of all other plants.
For middle school students, it is important to draw the distinction between non-native species and invasive species. Not all non-natives are “bad”. One can think of it like diversity in a community of people. Newcomers to a community are welcome and bring new points of view and new ways of doing things. However, if a small group of newcomers start killing off all of the “natives” by crowding them out and taking all the resources then those newcomers are no longer welcome.
This activity plays a role in that the microhabitat survey allows students to observe that there is an extreme difference between those students who have a microhabitat in the ivy covered area and those who have a microhabitat elsewhere along the creek bank. They observe first hand how ivy is invasive and can come to the definition of a native species, non-native species, and invasive species through their own observations. We then decide upon an action plan to restore the ivy area to a more native state and begin our restoration activities. At the end of the year we repeated the microhabitat survey to see how well we did with our goals.
Depending on the message you wish to convey with your own students, the focus of this investigation will vary. I chose to assign half the students sites in the ivy area that we plan to restore and the other half sites in a previously restored area. Other ideas include investigating shaded versus sunny microhabitats, schoolyard versus garden habitats, organic versus fertilized garden habitats, and virtually any other comparison you can imagine.
Student Prerequisites
Soil analysis skills (see Soil Analysis Lesson).
Basic understanding of habitats and ecosystems (see Terraqua Columns, Food Chains, Food Webs, and Ecosystem Organization Lessons).
Ability to use a field guide (see Food Webs Lesson).
Getting Ready
For habitat survey:
- Soil separation: 15 ml tubes, alum, ruler, labels, 2 different soils labeled in plastic cups, spoons
- Tullgren Funnel: lightbulbs, funnels, cheesecloth squares, funnel holder, petridishes or cups, labels, 2 different soils labeled in plastic cups, spoons
Lesson Plan
For habitat survey:
- What similarities did groups find? Why might those similarities exist?
- What differences did groups find? Why might those differences exist?
- Why did you find certain things surprising? What did you expect at the beginning?
- These small habitats are considered microhabitats. What factors in the environment might create microhabitats? (examples include a road or path that divides one area from another, areas of shade or sunlight, proximity to a water source, etc.)
- What creatures might live their whole life in only one microhabitat? What creatures wander from one microhabitat to another?
- Were we able to answer the question with the data we collected?
- Are there additional observations we could have or should have made to better answer the question?
- Is the area we studied a healthy habitat? Why or why not?
- Is the area we studied a sustainable habitat? Why or why not?
- What could or should be done to improve this area? Could we as a class do anything to improve it?
Assessment
Sources
The idea for this activity came from several other lesson plans designed for transect survey sites. I was inspired by the following lessons:
“On-Site Lesson Plan” in Monitoring Creek Health
“Activity 7: Microhabitats” in the book Environmental Science Activities Kit : Ready-To-Use Lessons, Labs, and Worksheets for Grades 7-12 by Michael Roa
“Weeding Out – River Plant Survey”, “A Matter of Trash – Pollution Survey” and “Macroinvertebrate Investigation” from Friends of the LA River’s science curriculum
See the Soil Analysis Lesson for source information about the soil analysis tests.
You can obtain 15 ml graduated test tubes from BD sciences.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
b. Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.
c. Students know populations of organisms can be categorized by the functions they serve in an ecosystem.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of
light and water, a range of temperatures, and soil composition.
Grade 8
Reactions
5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept:
e. Students know how to determine whether a solution is acidic, basic, or neutral.
All grades
Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform
investigations.
Summary
The study of ecology has many layers, ranging from the individual organism, to the population, to the ecosystem, to the planet. It is important for students to know the levels within this hierarchy and to recognize which level they are focusing on at any one time. For the purposes of this activity, students will learn about the different levels (organism, population, community, ecosystem, biome, and biosphere) by choosing an organism and the illustrating a pyramid about that organism. The result is a colorful display of organizational pyramids.
Objectives
Can define and explain the relationships among: individual organisms, populations, communities, ecosystems, biomes, and the biosphere.
Can explain some of the reasons why different regions of the globe have different climates, and thus support different biomes.
Can describe the characteristics of familiar biomes: tundra, desert, prairie (grassland), deciduous forest, tropical rain forest, ocean.
Vocabulary
Organism
Population
Community
Ecosystem
Biome
Biosphere
Tundra
Desert
Prairie
Deciduous forest
Tropical rain forest
Ocean
Time
45-55 minutes
Grouping
Individual
Materials
Teacher Background
In order to study ecology, scientists need to see how organisms are related to one another and also to the environment in which they live. To do this, it is useful to think about a hierarchy of ecosystem organization ranging from the individual organism to the biosphere.
To begin with, consider a single organism, the individual. An “organism” is any living thing, whether it is a human being, a germ, a rose bush, or a panda bear.
A group of organisms of the same kind is a population. A “population” can be defined as a group of interbreeding organisms living in the same area. You might imagine a human population such as the population of the city in which you live or the population of a certain country. The humans within that population live in the same area and can interbreed and have babies. Similarly, a population of dandelions might all live in the same field and share pollen or a population of dolphins might all live in the same body of water and have babies.
A community is the next largest level of organization. A “community” includes all the organisms, sometimes hundreds of different types, in a given area. Several different populations are usually found in a community. The populations within a community are interdependent because of the food webs that bind them together. Communities can vary greatly in size. For instance, you could consider the community within a certain forest or you could think about a community in a garden. In MyScienceBox, students study microhabitats and look at a community within a single square meter. Communities can be even smaller such as the community that lives on and inside a single human being. On our skin are various molds, yeasts, and bacteria. In our hair we may have lice. In our intestines are E. coli and other bacteria. Many microscopic critters live in our mouth. Thus, there is a community of organisms living in and on your body!
Until now, we have only considered the living things in an area. The next level of the organization, an ecosystem, begins to include the nonliving parts as well. An “ecosystem” includes all organisms in a defined area and their nonliving environment. When you study an ecosystem, you look at how the nonliving and living parts affect one other. When you study a community, you only look at how the living things affect each other. Like a community, an ecosystem can be large or small. The Earth is the largest of all ecosystems which is called the “biosphere”.
The Earth ecosystem can be divided into several major biomes. A “biome” is one of several major types of ecosystems found on the planet. Each biome is characterized by a particular type of vegetation. Biomes generally encompass large geographical areas and are not sharply delineated (one will blend into another). You probably are already familiar with the major biomes already: desert, rainforest, grassland, tundra, coniferous forest, deciduous forest, and mountain. Some include the ocean as a non-terrestrial biome. One important point is that even though a biome like a rainforest will be similar anywhere in the world – all will have large trees, vines, many bird and animal species, etc. – the exact type of species of tree and the exact type of vine will vary from rainforest to rainforest. Thus in one kind of biome, different organisms will occupy the same niche. These organisms tend to be similar in form but often come from very different evolutionary backgrounds (for instance, consider the numbat, an Australian marsupial anteater, and other mammalian anteaters around the world including the giant anteater and the armadillo).
Student Prerequisites
Some understanding of food webs is useful but not required.
Getting Ready
Lesson Plan
Assessment
Use a quick quiz the following day to test vocabulary retention. For example:
Match the example to the correct word. Write the letter of the correct word in the blank beside the example.
a) ecosystem
b) community
c) biome
d) individual
e) population
f) biosphere
____ Rosie the rattlesnake
____ rattlesnakes, mice, small birds, crickets, grass, hawks, cacti, and tumbleweed
____ the entire planet Earth
____ the community, the water, the air, the rocks, the soil, and the mountains
____ a desert
____ all the rattlesnakes in the area
Sources
For more information about biomes around the world, see the Blue Planet Website
For more information about Biosphere 2, see the official website of Biospheres 2 or this Biosphere site that contains additional information about the research and history of the project.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
c. Students know populations of organisms can be categorized by the functions they serve in an ecosystem.
d. Students know different kinds of organisms may play similar ecological roles in similar biomes.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Summary
Once students understand the concept of populations, it is important to introduce the idea of population change. There are many reasons for population change – limited resources, predator-prey cycles, human impact, habitat change – to name but a few. In this activity, students learn to graph population data and then use their graphs to evaluate one of the most famous examples of population change, the predator-prey population cycle of the snowshoe hare and the Canada lynx. The data is taken from the 300 years worth of real data collected by trappers of the Hudson Bay Company. This activity provides students a chance to look at real data and make some hypotheses about what causes population change in the real world. The Going Further section is more extensive than for other lesson plans on this site and refers teachers to many excellent population change activities that can be found in other curriculum guides.
Objectives
Can define population.
Can graph changes in a population over time.
Can interpret graphs and identify causes of population change.
Can see how available resources determine the number and type of organisms that environment can support.
Vocabulary
Predator
Prey
Population change
Time
45-55 minutes
Grouping
Individual
Materials
Teacher Background
After learning about habitats, food webs and food chains, students can begin to discover the relationships between organisms and between organisms and their environment. A key to many of these studies to the investigation of how populations change over time.
Populations are always changing. Sometimes changes are the result of humans interfering with food webs or habitats. But even when humans do not interfere, populations will still naturally shift up and down or fluctuate. As an example, we will look closely at the relationship between the Canada lynx and its primary prey, the snowshoe hare – an example touted in nearly every ecology textbook and population biology course.
The snowshoe hare is a common species of rabbit found in North America, its range extending throughout Canada, Alaska, and into the northern United States. One distinctive quality is its 2 different coloration patterns – brown in the summer, and white in the winter to better camouflage with the snow. Its diet consists of grasses, berries, twigs, bark and leaves.
The Canada lynx is a wild cat that resembles a large house cat with a short tail and prominent tufts on its ears. It is very secretive and even experienced hunters rarely see one in the wild. Its range overlaps with the snowshoe hare, on which it almost exclusively preys upon.
For over 300 years, the Hudson Bay Company has been involved in the fur trade in Canada. Detailed company records list the number of snowshoe hare pelts and the number of lynx pelts collected by hunters and trappers every year since the late 1700’s. The data shows a 200 year history of cyclical population booms and busts in the snowshoe hare population and a slightly delayed population boom and bust in the lynx population. Native Americans observed this cycle long before Europeans began trapping the hares and lynx for their pelts. Yet there are many competing theories to explain why the populations cycle in so dramatic a fashion. These theories include:
During peak years, the hares devour all the available vegetation and quite literally breed like rabbits until the environment can no longer support their blossoming population. As the hares become weakened by starvation, the lynx are better able to find and kill them, adding to their decline. The population does not reestablish itself immediately because it takes time for the vegetation to grow back.
Another theory is that the lynx population determines the hare population. As the number of hares increases, so does the numbers of lynx that survive to eat them. Soon, there are too many lynx for the number of hares and the lynx eat away their favorite food until they too suffer a population decline until the hare population can start growing again.
Lastly, there is evidence that at the peak population levels, the hares become so stressed by the increasing numbers of predators that they no longer reproduce at the same rate. Their population falls both as a result of the lowered reproductive success and the sheer number of lynx that are out to eat them.
Although the subtleties of these theories may be too complex for the typical middle schooler, their understanding of food webs and intuitive understanding of predator-prey relationships will likely enable them to piece together the general picture well enough for it to make sense.
Student Prerequisites
A clear understanding of food webs (see the Food Web activity).
An intuitive understanding of predator-prey relationships.
Experience with graphing data on an x-y coordinate system. This is essential! For students only recently introduced to graphing, consider giving students the completed graph and carefully walk them through its interpretation.
Getting Ready
Lesson Plan
- Notice how the hare population begins to increase over time until it reaches a peak. Why do you think that the numbers of hares are increasing at this time?
- Notice how the hare population begins to decrease after the peak. Why do you think that the numbers of hares is decreasing at this time?
- In general, are there more lynx or more hares? Why?
- Do the peaks in the lynx graph line up exactly with the peaks in the hares graph?
- When the hare population increases, what happens to the lynx population? Why?
- Look at the lynx population in 1903 and 1904. Think about what is happening to the hares at this time. Is the presence of more lynx helping the hares or hurting them? Why?
- Look at the lynx population in 1904 to 1906. Why is the lynx population declining?
- Do you think that this pattern is still happening today?
Assessment
Sources
Of the many websites that explore the relationship between the hare and the lynx, by far the most dynamic and engaging is CBC Television’s production of Walking with Ghosts. The Overview section has detailed information about the hare, lynx, population cycles and even about predator biologists. Unfortunately, I was never able to figure out how to order a copy of the program. Please add a comment if you are able to get a copy!
Other resources about the hare-lynx population cycle include:
Standards
Grade 6
Ecology (Life Sciences)
Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Summary
The management of the world’s fisheries is a controversial current issue that involves individuals from many different viewpoints – fishermen and women, environmentalists, park rangers, politicians, and shoppers at the seafood counter. The issue is that many of the world’s fisheries are overfished and have collapsed or are on the verge of collapse. This is but one example of the tragedy of the commons – where a limited common resource is overused because each individual person thinks, “If I don’t use this resource first, then somebody else will.” Students in this activity act as fishermen and women who need to share an ocean of fish and take in a catch. Groups soon realize that if they don’t set fishing limits and monitor the fish population, soon there are no fish left in the ocean.
Objectives
Can define population.
Can graph changes in a population over time.
Can see how available resources determine the number and type of organisms that an environment can support.
Can see how humans impact natural resources.
Can identify common natural resources that humans impact.
Can devise strategies to manage natural resources.
Vocabulary
Fishery
Overfishing
Collapse
Tragedy of the commons
Sustainability
Resource management
Time
45-55 minutes
Grouping
Teams of 4 students
Materials
Teacher Background
The tragedy of the commons was initially proposed as a hypothetical model to illustrate a much larger societal problem. In colonial times, there was often a common pasture (the commons) where all citizens of the town could take their livestock for grazing. Each individual farmer and his animals is motivated to use this pasture land to get the maximum benefit possible. However, as more animals use the resource, the pasture gets trampled and overgrazed until there is no grass left for anyone. Thus, if each farmer is motivated simply to maximize personal benefit, thus using the pasture as much as possible, the resource is soon no good to anyone.
Similarly, the ocean’s supply of fish is a common resource that is rapidly being depleted. The basic issue is that since 1950, the fishing industry has quadrupled its catch. According to the United Nations, 15 out of the 17 world fisheries are overfished or depleted. 90% of the large fish species in the oceans have been fished out in the last 50 years. In short, fish are being taken from the oceans faster than they can reproduce and grow. Many fisheries have already collapsed, sending hundreds of fishermen and women out of work. Without clear international controls and regulation, soon there will be no more fish in the seas. Many articles have been published in recent years describing the problem. For example, see the Economist, May 2005, Science Magazine, December 2003, and the San Francisco Chronicle, October 2004.
This activity is a way to help students recognize the problem by catching candy, peanut and cracker fish from paper plate oceans. Students will spend 4 years fishing in their oceans. Each “year” the students have 30 seconds to fish for as many fish as they can catch using straws and masking tape as their poles and hooks. Each fish has a different monetary value and each student much catch a minimum dollar amount of fish in order to stay in business the following year. Then the remaining fish in the ocean have a chance to reproduce. There must be at least 2 fish of that species to reproduce. In addition, the fish in their oceans have a food web and must have their food source still available in order to survive.
At the end of the game, some oceans will likely have overfished their fishery until there are no fish left. Others will have developed a strategy in order to maintain a sustainable fishing industry. The discussion at the end will look at the problem of overfishing and solutions that lead towards sustainable resource management. The stage is then set for solid discussions of resource management strategies for other shared environmental resources.
Student Prerequisites
Students need a solid understanding of food webs (see Food Webs activity) and experience with monitoring population changes over time through tables and graphs (See Hare and Lynx Population Change activity).
Getting Ready
Lesson Plan
- 4 fisherpersons will be fishing in each ocean (a paper plate). You cannot touch, tip or move the ocean!
- Each fisherperson will be given 2 fishing poles (straws) and a net (a short length of tape) to fish with. There should be NO fishing with hands! Each fisherperson will also get a boat (a napkin) onto which any fish that are caught should be placed. Fish that fall out of the boat onto the table do not count!
- You will be fishing in your ocean for 4 years. Each year you will have 30 seconds to bring in your catch.
- There are 4 different kinds of fish in the ocean. Each is worth a certain amount of money on the market. Goldfish are worth $3, Peanut Fish are worth $5, M&M Fish are worth $5, and Peanut M&M Fish are worth $10.
- You must earn at least $5 of income each year to stay in business. However, you should try to earn as much money as possible.
- At the end of each year, the fish have a chance to reproduce. For every 2 fish of that species, they will make 2 baby fish. Fish mate in pairs. Single fish don’t reproduce.
- The fish exist in a food web and need to have food in order to survive. Goldfish eat seaweed of which there is always a lot in the ocean. Peanut Fish and M&M Fish eat Goldfish; there must be at least 1 Goldfish in the ocean for these fish to survive. Peanut M&M Fish eats both Peanut Fish and M&M fish; there must be at least 1 Peanut Fish and 1 M&M fish in the ocean for these fish to survive.
Assessment
Sources
The idea for this lesson came from Jen McGonigle, a science teacher from Haddonfield, New Jersey, who shared this activity during the Exploratorium’s Summer Teacher Institute.
Wikipedia has a wonderful summary of the tragedy of the commons. It includes an excellent review of Hardin’s original essay on the topic, historical background about where the concept of the commons originated, and many examples of modern commons problems: littering, air quality, water quality, population growth, logging, etc.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Grade 6
Resources
6. Sources of energy and materials differ in amounts, distribution, usefulness, and the time required for their formation. As a basis for understanding this concept:
b. Students know different natural energy and material resources, including air, soil, rocks, minerals, petroleum, fresh water, wildlife, and forests, and know how to classify them as renewable or nonrenewable.
All Grades
Investigation and Experimentation
7. c. Construct appropriate graphs from data and develop qualitative statements about the relationships between variables.
Summary
In order to help understand the complexity of the issues surrounding protecting endangered species, students read an article about the Channel Island fox published in the Smithsonian magazine in October 2004. They create and use food webs to better understand the reasons for the foxes decline. This is a superb follow up to the Food Webs activity.
|
Objectives Can recognize how habitat change affects the organisms living in that habitat. |
Vocabulary
Endangered species
Food web
Habitat
Time
30-45 minutes
Grouping
Individual
Materials
Copy of the Fighting for Foxes article (downloadable below or from Smithsonian Magazine).
Copy of the Reading Questions (downloadable below).
Field guide with information about golden eagles.
Field guide with information about Channel island foxes.
Setting
classroom
Teacher Background
The causes and complexity of protecting endangered species is a hot topic in the media and environmental policy. For students to become educated consumers of scientific information in the media, it is essential that they gain exposure to these issues and discover that saving an endangered species is never as simple as it seems. The Channel Island fox is a fascinating example because its story involves several other charismatic species, the bald eagle, the golden eagle, and feral pigs. I encourage you to seek out other articles describing the plight of endangered species in your local area. If you find any good ones, add your comments below to let other teachers have access to your resources.
Student Prerequisites
Students should have been exposed to the following concepts: food webs, habitats, and endangered species.
Getting Ready
Lesson Plan
Going Further
Sources
The original Fighting for Foxes article from Smithsonian Magazine is available free online. Several additional articles about the foxes and other endangered species in California are available through Smithsonian as well.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.
b. Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Summary
This section will give you information to help you plan a field trip to Point Reyes National Seashore. My classes went to Point Reyes for an overnight camping trip between lessons 7 and 8. The first day, we went to the Bear Valley Visitor Center and did a ranger led program called Monitoring Creek Health. After creek monitoring, we played and hiked at Linmatour beach before retiring to our campsite. The following day, we took a kayaking tour of Tomales Bay. Our kayaking guides taught the students about the wildlife and geology of the area throughout the trip. The happy and exhausted students and teacher then made their way back to school.
Objectives
Can apply knowledge about water and soil quality monitoring to real world creeks.
Can conduct a scientific investigation.
Can use a field guide to identify animals in the wild. HAVE FUN!
Time
2 days, 1 night
Bear Valley Visitor Center ranger program
This program gave students the opportunity to use their water quality monitoring skills in a real world situation. This program comes with a superb hands-on curriculum for use in the classroom before and after the program. Students create a map, measure the temperature, measure pH, measure dissolved oxygen, measure the channel width and depth, measure the velocity of the water, and survey the insects present in the creek. They briefly discuss their results as a group with the ranger but the bulk of the discussion happens when the data is brought home to the classroom. The Post-Visit Activities included in the curriculum are both excellent and essential to bring closure to the experience. The creek monitoring experience provides a springboard with which to plan a water and soil monitoring program at a local creek near the school.
You must make reservations in advance to participate in the park’s ranger led programs. In addition to Monitoring Creek Health, there are a number of other ranger led programs focusing on different aspects of geology, ecology and natural history. Reservation forms can be found on the Point Reyes website. Reservations must be in writing and are accepted on a first come first served basis. Call 415-464-5139 for available dates and more information.
Camping at Olema Ranch Campground
Olema Ranch Campground is a privately owned campground located half a mile from the Park. Several large group sites are available. Tent sites start at $25 per site. Each site accommodates up to 6 people and 2 cars. The facilities have showers, fire pits, picnic tables, and a general store. They also have games you can borrow such as horseshoes, croquet, shuffleboard and others. For more information, call (415) 663-8001 or e-mail the campgrounds at [email protected].
Kayaking with Blue Waters Kayaking
Our school has gone kayaking with Blue Waters Kayaks for many years – always with the greatest success. The program I can heartily recommend is the 6 hour paddle out of Inverness. Students learn the basics of handling a kayak then slowly make their way 1.5 miles along the bay to a lovely beach. There, students have lunch and explore the estuary and its wildlife before returning. While I personally have only been on the 6 hour kayaking programs with my students, Blue Waters can also arrange kayak camping trips along Tomales Bay. The prices for groups varies so contact Blue Waters directly for rates and information 415-669-2600.
Summary
At the end of the unit, students can now apply their understanding of ecosystems, food webs, resource management, native vs. nonnative species, and human environmental impact to a real world situation. Individuals involved in habitat restoration routinely research and select plants and animals to include in a redesigned ecosystem. In this final project, students will create posters with a minimum of 8 native plants and 5 native animals that should be included in the redesign of the habitat they surveyed previously. They will look at how these organisms will interact and discuss how to sustain the ecosystem into the future. If it is possible to do a long term habitat restoration near your school, this is an excellent exercise to get the students personally invested in the restoration work because they played a role in selecting the species they will reintroduce.
Objectives
Can research plant and animal species using field guides.
Can identify and describe organism-environment interactions and organism-organism interactions in an ecosystem.
Can conceptualize an ecosystem working together as a whole rather than as individual plants and animals living independently in an environment.
Can recognize the benefits of biodiversity.
Can see our role as environmental stewards with a mission to sustain and nurture our local ecosystem.
Can apply classroom knowledge to real world data.
Vocabulary
Biodiversity
Sustainability
Food web
Invasive species
Native species
Non-native species
Time
3-4 hours
Grouping
Groups of 2-3 students
Materials
Teacher Background
In this activity, students will put together all they know about food webs, habitats, ecosystems, and the interactions between organisms and their environment to try to design a diverse, balanced, and sustainable ecosystem. One of the most important things for students to recognize from this activity is the idea that an ecosystem works together as a unified whole rather than as individual plants and animals living independently in an environment. The plants depend on the available growing conditions of the topography, soil quality, water availability, temperature and sunlight. In turn, the animals depend on the availability of plants for food and shelter. And the whole ecosystem depends on us to set it up in a balanced way so that it can sustain itself in the long run.
Another key lesson is that of biodiversity contributing to greater ecosystem health and sustainability. In general, the more diverse an ecological community, the more likely it is to flourish in the long run. If multiple organisms fill each niche, then when trouble hits one organism, the role can still be filled by another. An interesting analogy can be made to diversity in human communities. You may want to consider opening the discussion of biodiversity with the question, “Why do we as teachers try to encourage diversity in the classroom? Why does diversity help make better communities?” Allow this to lead you into the idea of why biodiversity might lead to more sustainable ecosystems.
Finally, it is essential that you and the students have a very clear picture of the area that you will be designing the ecosystem for. The environmental conditions such as the landscape, sunlight, water, rainfall, soil quality, and general size of the space will greatly affect the types of plants and animals that can survive in that place. In addition, if the area is used or accessed by humans, that will greatly affect the types of plants and animals that can survive. Every plant and animal the students choose must be able to live in these conditions. Therefore, the more intimate the students’ knowledge of the environmental conditions, the easier it will be for them to keep those conditions in mind when choosing their species.
Student Prerequisites
A solid foundation in food webs, what ecosystems are, resource management, native vs. non-native species, and experience observing environmental conditions such as soil quality and water availability. Ideally, students would also have visited and explored the area they are designing their ecosystem for so they have first hand experience with the environmental conditions they are asking their plants and animals to survive in.
Getting Ready
Lesson Plan
- What are the relationships between the living and non-living parts of your ecosystem?
- How did your group maximize the diversity in the space you were given?
- What challenges arose and how did you overcome the problems?
- What guided you to choose one organism over another?
- How will the presence of humans and their pets affect the ecosystem?
- If your plan is implemented, how hard will it be for our class and future classes to maintain the ecosystem once it is established?
Sources
The idea for this project was adapted from the “Ecosystem Facelift” activity in Project WILD K-12 Curriculum and Activity Guide.
You will need to help give the students a head start by identifying some of the native plants and animals local to your area and the site they are designing their ecosystem for. I used the following resources:
Erica Campos put together a wonderful Creek Care Guide with the names of many local native plants found in riparian corridors.
The Piedmont Avenue Neighborhood Improvement League recently restored an area of the creek we were working on just a mile upstream of our adopted site. They created this listing of native plants that were selected for their project.
Another local creek organization, Friends of Sausal Creek, created this wonderful group of fact sheets about the plant and animal life near their creek. Of particular interest are the Tables of Biological Resources of the Upper Sausal Creek Watershed which lists many of the animals that can be found in and around their creek and the Gardener’s Guide to the Sausal Creek Watershed by Martha E. Lowe which contains detailed information about the many native plants that grow in our area.
In order to find lists of natives in your local area, try contacting nearby environmental organizations, creek groups, neighborhood groups, and local parks. The staff and volunteers at all these organizations are likely to be excited about your work and most will be enthusiastic about helping you gather information.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment.
Grade 6
Resources
6. b. Students know different natural energy and material resources, including air, soil, rocks, minerals, petroleum, fresh water, wildlife, and forests, and know how to classify them as renewable or nonrenewable.
Grade 6
Investigation and Experimentation
7. f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.
Grade 7
Investigation and Experimentation
7. d. Construct scale models, maps, and appropriately labeled diagrams to communicate scientific knowledge (e.g., motion of Earth’s plates and cell structure).
Summary
Once students have some experience working with a basic terraqua column (see the Terraqua Columns Lesson), they have an opportunity to design and conduct their own investigations with their mini-ecosystems. There are hundreds of variables students can manipulate with a minimum of materials – temperature, light, pollution, type of water, type of soil, etc. As a class, students brainstorm variables that might affect the plants, soil, and/or water in a terraqua column. In teams, students propose a project, and once approved, set about testing their ideas and observing the effects of their manipulations on their mini-ecosystem. If your school participates in a local science fair, this is a fantastic activity to introduce students to experimental design, variables, and control groups.
Objectives
Can use a lab notebook to design experiments, make observations, and draw conclusions.
Can design an original experiment.
Can explain what an experimental variable is.
Can explain the reason you need a control group to compare against.
Can keep track of and organize observations over a long period of time.
Can draw conclusions from results.
Can make connections between small scale models and real world events.
Vocabulary
Ecosystem
Variable
Control group
Experimental group
Hypothesis
Time
30 minutes to set the stage and brainstorm ideas
20 minutes to propose an experiment (more if you want students to conduct background research on their topic)
20 minutes to set up experiments
10 minutes a day, two to three times a week, for 1 month, to make observations and record results
30 minutes to organize results and draw conclusions
5 minutes per group to present the results to the class
optional: 45-50 minutes to create posters displaying scientific results prior to the presentation
Grouping
Teams of 2-4 students
Materials
Each team needs:
Teacher Background
Students are most engaged in learning when they can steer the direction of their own learning. In this lesson, students are able to design an original experiment, learn about experimental variables and controls, and present their results to the class. They use their experience with terraqua columns, water quality testing and soil analysis to guide their inquiry in a direction of their choosing.
To get a sense of what students might come up with, these are a few of the experiments my students conducted:
The Scientific Method
The scientific method is simply the process scientists use to learn about the world. Generally, the steps are
Variables
One unique element that makes science different than any other discipline is the controlled experiment. In science, we create theories based on evidence, and the evidence must be something that other people can repeat and observe for themselves. Every step of the scientific method centers upon understanding the need to control variables. So what is a variable and what does it mean to control a variable?
A variable is anything that might change in an experiment. Anything that you as the scientist change is a variable (like whether or not to put soda on your plants). Most everything that you measure and observe at the end of an experiment is a variable (like whether or not the plants grow and how tall they grow). And there are often variables that you don't even notice but can affect the experiments (the temperature in the room, how much time has passed, how damp the room is, whether the spoon you are using to measure materials is clean or not). An experiment has three kinds of variables: independent, dependent, and controlled.
The scientist changes the independent variable. In a good experiment there is only one independent variable. As the scientist changes the independent variable, he or she observes what happens. In our example, the independent variable is whether or not the scientist added soda to the water compartment.
The dependent variable is what you measure and want to know about in your results. The dependent variable changes in response to the independent variable. For example, the dependent variable is the height of the plants, the pH of the soil and the pH of the water.
Experiments also have controlled variables. Controlled variables are quantities that a scientist wants to remain constant, and he must observe them just as carefully as the dependent variables. For example, if we want to measure the difference in the height of plants in soda versus water, it is essential that we use the same kind of seeds in both terraqua columns. If we use radish seeds in one column and carrot seeds in the other, we can't be sure if the carrot seeds with soda grew more slowly because of the soda or because carrot seeds normally grow more slowly than radish seeds. Similarly, we want to make sure that they get the same amount of light, that they have the same type of soil to grow in, and that they stay the same temperature.
In a controlled experiment the scientist has considered all 3 types of variables. She tests a hypothesis by changing the independent variable and noting the effect on the dependent variables, all the while making sure that controlled variables stay the same. Good experiments make it so that the only difference between the control group and the experimental group is the independent variable.
Experimental and Control Groups
In many experiments, such as these terraqua column experiments, the scientist makes a comparison between different groups. The group that does not receive any treatments - the one where the independent variable is not changed - is called the control group. For example, a plant with no fertilizer. The group or groups that do receive a treatment - the ones where the independent variable is changed - is called the experimental group. It is essential to have a control group in these types of experiments or you will not be able to determine if a plant that got a treatment is any different.
When all of these details are taken care of, and when a difference in the dependent variable exists, then the experimenter can say it was the independent variable that caused the difference. There have been plenty of bad experiments in the real world. So, a smart scientist (and a good students) will look to see exactly how the experiment was designed and conducted in order to determine if the conclusion drawn from the data is really true.
Student Prerequisites
Student should have:
Getting Ready
Lesson Plan
Brainstorming, researching and proposing an experiment
| pH of the water | ||
| Date | Column with fertilizer | Column without fertilizer |
Sources
Botle Biology contains everything you wanted to know about terraqua columns.
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
Investigation and Experimentation
Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:
Grade 6
a. Develop a hypothesis.
b. Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.
c. Construct appropriate graphs from data and develop qualitative statements about the relationships between variables.
d. Communicate the steps and results from an investigation in written reports and oral presentations.
e. Recognize whether evidence is consistent with a proposed explanation.
Grade 7
a. Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.
e. Communicate the steps and results from an investigation in written reports and oral presentations.
Grade 8
a. Plan and conduct a scientific investigation to test a hypothesis.
b. Evaluate the accuracy and reproducibility of data.
c. Distinguish between variable and controlled parameters in a test.
e. Construct appropriate graphs from data and develop quantitative statements about the relationships between variables.
Summary
This is an alternative assessment activity in which students pull apart a rotting log as an example of a microhabitat that can be explored in the classroom. As they dissect the log and discover the myriad of bizarre creatures on and inside the log, the notes the students keep can be used as an assessment of many of the major concepts in this unit. Another use for this lab is as an engaging way introduce a very special organism-organism relationship, symbiosis. Termites have a symbiotic relationship with the protozoa in their gut. The protozoa that digest the cellulose in the wood for the termites, can be extracted from the termites’ gut and observed under a microscope. One of my students who witnessed the extraction and then saw the protozoa proclaimed “That was the coolest thing I have ever seen. Ever.” Finally, if you are just fascinated by termites and want to become completely enamoured, try putting a termite on a line drawn by a Bic pen…
Objectives
Assessment or continued exploration of microhabitats
Vocabulary (Optional)
Symbiosis
Pheromone
Time
45-55 minutes
Grouping
Groups of 4-6 students per log
Materials
For each student:
Teacher Background
I used this activity as a lab-based test that the kids didn’t actually think was a test. It was a super way for them to reveal the holes in their understanding before the written test. Some of the major concepts that can be assessed in this lab include differentiating between a community and an ecosystem, creating food webs, identifying interactions between organisms and between organisms and their environment, predicting the effects of human impact on populations, and assessing ecosystem sustainability.
In addition, I was able to show them an amazing symbiotic relationship between termites and protozoa. Termites eat wood but cannot completely digest the wood on their own. Many varieties of protozoa, single celled animals with amazingly varied modes of locomotion, live in the termites hindgut and help digest the cellulose in the wood. They attach themselves to the inner wall of the termite’s gut to keep from being excreted with undigested wood particles. In return for their invaluable services, the protozoa get a nice, safe home and a constant supply of food.
Student Prerequisites
Knowledge of food webs, ecosystems, organism-environment interdependence, and sustainability.
Getting Ready
Lesson Plan
- List as many organisms in the ecosystem as you can find. For each organism, draw a picture and label it with a name that describes the organism like “light-brown, long bodied ant-like thing” or “2 cm-long black beetle”. More things are living than you might think…
- List as many non-living parts of the environment as you can find. There is more than just wood – think about solids, liquids AND gases!
- Which of the things you just listed are part of the log community?
- Which of the things you just listed are part of the log ecosystem?
- What is the difference between a community and an ecosystem?
- Find evidence about the food webs that make up the community. Do you see any organisms eating? Do you see any “poop” that gives a hint about what the organisms have been eating? Draw as much of the food web as you can.
- Describe one organism-organism interaction that you observe.
- Describe one organism-environment interaction that you observe.
- How will this lab impact the populations of organisms in your log? Pick one organism and describe how the population of this species will be affected by our investigation.
- Is this ecosystem sustainable? Why or why not? Use your observations to support your idea.
- If you have a protozoa viewing station set up, invite groups one at a time to come visit you at the microscope to see the protozoa.
- Reserve plenty of time to clean up.
Going Further
Another cool termite trick… Did you know that termites mistake the smell of a Bic pen for a pheromone that they use to navigate? Pheromones are chemicals that communicates a message to other members of the same species. Although humans do have pheromones, termites and other social insects communicate extensively through these chemical messages. Termite workers indicate the path to a food source by leaving behind a trail-pheromone. A chemical in Bic pens (not other pens for some reason) mimics the trail-pheromone. If you draw a line with a Bic pen on paper then place a termite on the line, the termite will faithfully follow the line wherever it leads. Try drawing curly-Qs and other shapes. See what happens when a termite hits a crossroads. Try pens by other manufacturers. Try different colors of Bic pen.
Sources
The idea for this activity came from a workshop by Karen Kalamuck at the Exploratorium. THANK YOU Karen!
If you just can’t be bothered to go find rotting logs but really want to try the termite activities, termites can be ordered from Carolina Biological with instructions for how to isolate the protozoa ($11.25) OR with instructions for how to draw lines with Bic pens ($32.75).
Standards
Grade 6
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment.
All Grades
Investigation and Experimentation
7. Scientific progress is made by asking meaningful questions and conducting careful investigations.
