Unit title - College of Engineering



Biology

Introduction

Objective:

The goal of this week-long study of biology is to give the students an understanding of what conditions are necessary for life. They will learn what these conditions are, how they are obtained, and what will happen if they are not met. They will also learn what types of things biologists study.

Background:

Biology is the study of life. “Bio” means life, and “ology” means “study of”. Biologists study living things and life processes. There are many different types of “-ologists” that study different aspects of life (see “Types of Biologists). Life is what makes a rock different from a plant. During this week the students will learn what “life” is and how it is maintained. There are seven characteristics that an object must display in order to be considered alive. It must grow, move, take in nourishment, reproduce its own kind, respond to stimuli, breath, and excrete waste materials. There are many objects that display one or more of these characteristics that are not alive. For example, some machines move and respond to stimuli, but they are not alive. A photocopier reproduces, but it is also not alive. An object must display all seven of these characteristics.

There are also certain things that are required to maintain life. An organism needs very few things in order to survive, despite what humans decide they “need” in order to live. They need only food, water, air, and shelter from intolerable weather conditions. Without food the organism will starve, without water the organism with become dehydrated, without air it will be asphyxiated, and without shelter it can die from weather conditions and exposure.

Different types of Biologists

Botanist- studies plants

Ecologist- studies relationships between organisms and their environment

Entomologist- studies insects

Herpetologist- studies amphibians and reptiles

Ichthyologist- studies fish

Paleontologist- studies fossils and ancient life forms such as dinosaurs

Pathologist- studies disease-causing organisms

Ornithologist- studies birds

Zoologist- studies animals (often broken into invertebrate and vertebrate)

Biology

State Standards and Benchmarks

Oregon Standards for 3rd and 5th grade

Life Science- Diversity/ Interdependence

Oregon Common Curriculum Goals:

Understand the relationships among living things and between living things and their environments.

Benchmarks:

Grade 3: Describe a habitat and the organisms that live there.

Grade 5: Describe the relationship between characteristics of specific habitats and the organisms that live there.

Life Science-Organisms

Oregon Common Curriculum Goals:

Understand the characteristics, structure, and functions of organisms.

Benchmarks:

Grade 3:Recognize characteristics that are similar and different between organisms. Describe the basic needs of living things.

Grade 5: Group or classify organisms based on a variety of characteristics. Describe basic plant and animal structures and their functions.

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Physical Science-Energy

Oregon Common Curriculum Goals:

Understand energy, its transformations, and interactions with matter.

Benchmarks:

Grade 3: Identify common types and uses of energy.

Grade 5: Identify forms of various types of energy and their effects on matter. Describe examples of energy transfer.

Biology

Vocabulary

•

• Abdomen

• Agar

• Air

• Anal Fin

• Antennae

• Antibiotics

• Asphyxiate

• Bacterium (Bacteria)

• Budding

• Cap

• Carbon Dioxide

• Caudal Fin

• Chlorophyll

• Coal

• Compound eye

• Conserve

• Consumers

• Contaminate

• Cotyledon

• Culture

• Decomposers

• Dehydrated

• Desiccated (Dried Out)

• Domino Patterns

• Dormant

• Dorsal Fin

• Ecosystem

• Energy

• Energy Loss

• Exponential Growth

• Eye

• Food

• Fungus (Fungi)

• Germ

• Gill Slit

• Gills

• Growth

• Habitat

• Head

• Herbivores

• Hypha (Hyphae)

• Jointed leg

• Leaf

• Life

• Mandibles (jaws)

• Medium

• Microorganisms (Microbes)

• Mouth

• Mushroom

• Mycelium (Mycelia)

• Natural Gas

• Natural Resources

• Necrotic (Dead Tissue)

• Non-Renewable Resources

• Omnivores

• Organism

• Oxygen

• Parasite

• Parent Cell

• Pathogen

• Pectoral Fin

• Pelvic Fin

• Photo Response

• Photosynthesis

• Pigment

• Predators

• Primary Consumers

• Producers

• Renewable Resources

• Respiration

• Roots

• Scent

• Scent Consumers

• Seed Energy

• Shelter

• Simple Leaves

• Soil

• Solar Energy

• Spore

• Stalk

• Stem

• Surface Area

• Swab

• Thorax

• Transfer

• Transpiration

• Variable

• Veins

• Virus

• Water

• Yeast

[pic]

Biology

Lesson Index

Lesson:

Bean Growth

Dissecting Fungi

Energy Transfer

Environmental Swab Plate Growth

Feed the Yeast

Leaf Slide Show

M&M Resources

Make a Habitat

Observing Fish and Insect Parts

Nature’s Tea

Web of Life

Page:

8

11

14

16

20

23

27

30

33

37

39

Biology

Bean Growth

Grades K-5 (with variations)

Overview:

Students learn about the needs of a living organism by growing beans and studying what happens to the ones that do not have certain necessary things.

Time: 40 minutes set-up on day 1, 15 minutes observation on days 2-5

Materials:

For the class:

• Water

• Opaque bag (a paper bag works)

• Bean Growth Stickers (1 page)

For each pair of students:

• 1 Lima bean (a seed variety will work much better than ready-to-cook beans)

• 1 Bean of another variety

• Zip-loc bag

• Paper towel

• 1 Bean Growth Worksheet

Background:

In order to survive, a plant needs food, water, air, and light (another form of energy aside from food). If any of these are taken away the plant will not survive for any extended period of time.

A plant’s source of food for the first part of its life comes from inside the seed, rather than from soil. The first pair of leaves found inside a seed are known as a cotyledon, and they get their nutrients from the seed for the first few days of its life. Once the plant has roots, it is able to absorb soil nutrients from an external source in the soil. Upon germination, the cotyledon emerges, enlarges and becomes green.

Without water a plant will become dehydrated and die, just like an animal. Plants draw up water through the roots through a series of vessels and veins. Water is lost out the leaves through transpiration.

Just as people need to breath, plants also take in a gas and convert it into another gas, a process called respiration. Unlike animals, which take in oxygen and convert it to carbon dioxide, a plant takes in carbon dioxide and converts it to oxygen.

A significant difference between plants and animals is a plant’s use of light for energy, using a process called photosynthesis. The chlorophyll in leaves and green parts of plants makes this possible. Without light a plant will turn lighter color or white and will eventually die. Animals can not perform this function and we must get our energy through other sources, such as eating plants or eating animals that have eaten plants. Otherwise, we could feed ourselves by standing in the sun!

Setup:

Some beans will need to be soaked overnight so that they are soft enough to pull open. Be careful not to soak them so long that they fall apart. Most of the beans can just be left in a wet paper towel overnight.

Activities/procedure:

Pass out a zip-loc bag, a paper towel, a lima bean, and another bean variety to each of the students. Decide, in groups of five (leaders may need to participate or make extra bags), who is going to take away food, water, air, OR light, (each student will only remove one variable) and who will give the plant everything it needs (perhaps the leader). Label each bag accordingly. Place the two beans inside a folded paper towel and put them in the zip-loc bag.

For the beans that get everything (the control): pour a small amount of water into the bag to wet the paper towel. You don’t want it to dry out, but you don’t want lots of standing water, or the seeding will rot. Leave the bag open and in a well-lit area, but not in direct sun. These beans should sprout the best, and in about 5 days, they should have green leaves starting to uncurl and roots growing through the paper towel. At this point, they will have almost used up the nutrients supplied by the seed, and they will be searching out more from the soil through its roots. The green color in the leaves indicate that they are starting to undergo photosynthesis and are producing chlorophyll.

For the beans that get no food: After soaking the bean in water, remove the seed coat, separate the halves of the seed and remove the small plant from inside. This is the cotyledon. This seedling will not be able to feed off of the bean. The small cotyledon will dry up quickly and die in the absence of nutrients.

For the beans that get no water: If the beans have been soaked, leave the paper towel dry. Place the bag open in a well-lit area. If they have not been soaked, wet the paper towel like the others, however, give it no more water. This bean may sprout if it is wet in the start, but it will not continue to grow in the absence of water.

For the beans that get no air: Wet the paper towel, seal the bag and leave it in a well-lighted location. This bean may actually sprout quite well, and look good at first. There is not a huge amount of air underground where these beans start to grow. However, after a few days without air, the sprout will start to get limp and look wimpy. Without the gas exchange from respiration, the seedling will soon die.

For the beans that get no light: Wet the paper towel, leave the bag open and place it inside another bag that will not allow light to come in, such as a paper bag. This bean will probably also look pretty good at first, since there is no light underground, and seeds will sprout in the dark. The sprouts will then grow towards the light, and the roots away from it, which is called a photo response. By the end of the week, these sprouts may start to look lighter in color and will probably not grow as vigorously as the sprouts exposed to light.

On the following days, add water to each of the bags (if needed), except the one that gets no water, and leave them in the same condition as before. Have the students make observations and draw pictures about the growth of their plants. Compare the growth of the beans under different conditions in each group.

Extension: “Inside a Seed”

Ask How does a plant begin? How does a seed turn into a plant. Give each student a seed been that has been soaked in water so it is easier to open.  Show them how to open the seeds carefully.  (They fall apart, so you must be gentle!)  Ask students to see if they can find out how a seed turns into a plant.  They should be able to find a small white or pale green cotyledon, or baby plant. After looking on their own, have them help friends find out why.  Have them talk about it with their groups as they look.  Make sure every child sees a baby plant. Have they label the seed and the baby plant on their Dissecting Plants and Seeds worksheet.

Discussion:

• Talk about the needs of a plant. It needs food, water, air, and light. Compare that to what an animal needs.

• Which plants grew the best (under which conditions)? (Plants with all of the resources)

• Why didn’t some of the plants grow? (Plants need all four to grow well)

• What happened to each of the plants that had something taken away? (They died/withered/did not grow as well)

Vocabulary:

• Chlorophyll

• Cotyledon

• Dehydrated

• Growth

• Life

• Photosynthesis

• Photo Response

• Respiration

• Transpiration

• Variable

Biology

Dissecting Fungi

Grades K-5 (with variations)

Overview:

Students will learn the different parts of fungus and compare them to the parts of a seed plant.

Time: 20-30 minutes

Materials:

For each student:

• An “Observing Seed Plants” and mushrooms worksheet

For each student pair:

• 1 mushroom for each student- grocery store variety

• 1 plastic knife

• 1 paper or plastic plate

• 1 magnifying glass

Teaching/demo materials:

• Either and overhead of the worksheet answer key or an individual key for each group

• A seed plant that can be used for part comparison. A house plant or vegetable start works well.

Background:

There are over 100,000 different species of fungi. The largest are several feet in diameter, while the smallest are microscopic.

Plants reproduce using seeds, which sprout to form a seedling. Fungi reproduce by way of spores, which do not sprout. Instead, they send out threadlike hyphae which form a web like mass of mycelia (plural mycelium).

Fungi are generally classified by the type of structure that forms the spores. Two fungi that kids will be familiar with are mushrooms and mold. Spores on mushrooms are found in gills, compared to molds for example, which have spore cases that contain spores.

Mushrooms have many comparable parts to a seed plant. The mycelia of a mushroom are similar to the roots of a plant. The mushroom stalk is like a plant stem in that they both provide support. Seeds and spores can also be compared to each other, since they can both produce new organisms. The gills in mushrooms, and the spore cases in mold, are comparable to the flowers of flowering plants in that they are where propagative structures are formed.

The cap of the mushroom is only similar to a leaf in that it may provide some shelter to the reproductive structures of the organism. However, the cap does not provide food for the mushroom like a leaf does for a plant. Fungi do not undergo photosynthesis, has no chlorophyll, and is not green. It must get its nutrients from the things on which it grows. Fungi play an important part in our ecosystem, in that they act as a decomposer that breaks down dead organic matter.

Setup:

You must buy mushrooms at the grocery store shortly before this activity. Provide each team with the required supplies.

Activities/procedure:

Tell the kids that these are not poisonous mushrooms, but that many mushrooms are. They should never pick wild mushrooms without an adult present, and they should NEVER taste them! Review the “no tasting” rule for this activity. Talk to them about using the plastic knife carefully and always cutting away from themselves. Even a plastic knife can be dangerous!

Start off by observing a seed plant, and labeling all of the parts on the worksheet. Review what each of the structures do.

Have the kids remove the stem of their mushroom by carefully twisting it. They can then peal back the membrane over the gills and observe them. Now allow the kids to explore their mushroom by having them carefully cut into the different parts of their mushroom. As they do this, have them hypothesize what each structure is for, as they fill it out on their worksheet.

It is not a good idea to allow students to taste even grocery store mushrooms. Aside from health code issues, there also may be mushroom allergies. Plus, there seems to be a gag response that many younger kids experience when they try mushrooms. Personal experience, don’t ask.

Have the kids clean up their own area, and dispose of the mushrooms, then lead a discussion.

Discussion:

Questions to ask:

• Does the mushroom get energy from the sun? Does it contain chlorophyll? (No- if it did, it would appear green. It gets its energy from decaying matter.)

• How does a mushroom reproduce? (spores produced in the gills)

• Where are the mushrooms mycelia? (they get cut off when harvested)

Vocabulary:

• Cap

• Fungus (Fungi)

• Gills

• Hypha (Hyphae)

• Leaf

• Mushroom

• Mycelium (Mycelia)

• Roots

• Seed

• Spores

• Stalk

• Stem

References:

Fungi- Small Wonders. Delta Science Module- DSM II. 13-18.

Biology

Energy Transfer

Grades K-5 (with variations)

Overview:

This activity is a fun outside water game that uses cups of water with holes in them to teach students about how energy is lost each time it is transferred between organisms. It also reinforces the idea of interconnectivity between species and the concept of a food chain.

Time: 20 minutes

Materials:

For the class:

• 5-Five gallon buckets

• Access to large amounts of water (hose)

For each student:

• Large labeled Styrofoam cups or plastic containers (we used 64oz cups) with holes poked in the bottom.

Background:

When energy is transferred between objects, some is converted into non-reusable forms. The same holds for the transfer of energy between plants, animals, and food products. When more changes occur, more energy is lost. As a result, it takes more energy to create a hamburger than a garden burger because there are more steps involved. To create a garden burger, the energy comes from the sun, is absorbed by the soil and plants, and the plants are made into a burger. To make a hamburger, one more step is added when the cow then eats the plant and is later consumed by a human.

Setup:

Label each of the cups with one of the following: sun, soil, plant, garden burger, cow, hamburger, or human. Arrange the cups in two different teams that will compete against each other.

Team 1: Sun ( Soil ( Plant ( Garden Burger ( Human

Team 2: Sun ( Soil ( Plant ( Cow ( Hamburger ( Human

Place a bucket full of water at the end of each row next to the sun, and place an empty bucket next to each of the humans. You may have to make extra cups to adjust for the number of participants. If there is a large group doing this, it may be better to have two rounds or to run two simultaneous races. If the chain of participants gets too long, then none of the water makes it to then end!

Activities/procedure:

Have each student stand in front of one of the labeled cups, but to wait to pick them up until after the instructions. This activity is a good one for hot summer days! You may have to remind the kids that this is not a water fight.

This activity is a race to see who can get the most water, which represents energy, from the full bucket next to the sun to the empty bucket next to the human. The students with the sun cup must fill their cups and then pass the water by dumping it into the next student’s cup. The water will travel down the line in this way until the last person dumps it into the bucket. The holes in the bottom of the cups represent the energy lost during the different transfers.

Start the two teams at the same time. When the buckets get low on water, call “stop”. Measure the amount of water in the ending buckets using comparison. This is easiest if the buckets are the same size, and it is possible to see the water line through them.

The team with more people (the hamburger and the cow) should lose every time because they have more chances to lose energy before reaching the bucket. If both teams are very quick at this game, (which at times is the case with older kids) the difference is often so slight that it is unnoticeable, but still apparent. Younger kids may have difficulty with the coordination involved with transferring water, so they may need some help getting any water to the end of the line at all!

Some kids will swear it was just because one team was faster, so you can mix up teams and try it again, where they will find that the team with more people always loses. If it is hot, the kids will not complain about doing it a few times!

Discussion:

Questions to ask the students:

Which team had the most energy at the end? (The team with less people, less energy sinks)

Which team lost the most energy? Why? (The group with the most people lost the most energy because they had to pass it the most times. The same thing happens in nature with energy. It takes less energy to make a soy burger than a hamburger.)

Vocabulary:

• Energy

• Energy Loss

• Transfer

Biology

Environmental Swab Plate Growth

Grades K-5 (with variations)

Overview:

Students get to culture their own microbes (bacteria and fungus) in a Petri dish filled with agar and watch it grow over time. They will find out that there is a large variety of life that grows when given the right conditions.

Time: This is a 5 day experiment requiring 2 hours plate preparation, 30-40 minutes to collect samples on day 1, and 10-15 min per day on days 2-5.

Materials:

For each student:

• 1 Environmental Swab Plate Growth Data Sheet

For each student pair:

• 1 prepared agar plate

• 1 sterile cotton swab

For the each group:

• Masking tape

• Permanent markers

• A tray or box to carry the groups plates on

Teaching/demo materials:

• Sample photos of microscopic organisms

Background:

Microbes or microorganisms are very small living things that we can not see without the aid of a microscope. Bacteria, fungi and viruses, are all microbes. Students will be growing bacteria and fungi in this exercise. Many are very important to the function of all life. They can live any were from your stomach to the bottom of the sea floor to the grass.

In this activity, the students will be growing a culture, which is cultivating living material in a nutrient media. Microbes will grow in a Petri dish filled with agar, (which comes from red alga/ seaweed), and animal proteins, (from the brain and heart of a cow). This mixture will act as our growing medium, which is an environment where something functions and thrives. It acts as the food and the habitat for the microbes and will allow us to grow many different types of microbes

All microbes are often referred to as a germ, and many kids will know them as such. However, for this exercise, try to be consistent and refer to germs as the microbes that cause disease and make us sick. Another name for them is a pathogen. Emphasize that not all microbes will make us sick.

Bacterium (pl. bacteria) is any of numerous sometimes parasitic unicellular organisms having various forms and often causing disease. Bacteria will probably be the first thing that grows on the agar medium.

A fungus (pl. fungi) is a large group of organisms including yeasts, molds, and mushrooms, which lack chlorophyll. Some of the growth in this experiment may be fungal (mold) growth. The medium starts to mold after being out of the refrigerator.

The kids will not grow virus in this experiment, but a virus may grow in a Petri dish if placed there. A virus is a any of a large group of submicroscopic infective agents that are regarded either as extremely simple microbes, or extremely complex molecules. They have a core of nucleic acid (RNA or DNA) and are surrounded by a protein coat. They are capable or invading and destroying living cells and causing the release of a large number of new particles identical to the original one, thus producing a disease.

There are three things that can make us sick—parasites, viruses, and bacteria (there are four including poisons, but they can be disregarded for this exercise). Parasites, which are multi-celled organisms that infest another organism, are the largest disease causing agent. Parasites cause sickness by multiplying inside their host and drawing nutrients away from it. Some feed off of the host itself, causing more direct damage.

Viruses are the smallest of the three and cannot be killed by medications. Once a virus has been introduced to the body, the immune system creates anti-bodies that remain and create a permanent immunity to the virus. An immunization against a virus is done by introducing a small amount of the virus (usually in an inert state) that will not make the body sick, but will cause it to create anti-bodies, preventing future infection from the virus.

Bacteria are single-celled organisms that may sometimes causes illnesses. There is no way to immunize against them due to the rapid mutations of the cells, but they can be killed using antibiotics. Bacteria multiply quickly in welcoming environments. They cannot survive in extreme heat or extreme cold. Contrary to common belief, not all bacteria are harmful. Certain kinds of bacteria are necessary for survival. The bacteria in intestines digest food into nutrients the body can use. The bacteria living outside convert excrement and trash into dirt. Bacteria are asexual organisms. Only one is required for reproduction. In a culture dish the bacteria will multiply exponentially because each bacterium splits to form two, and those two split to create four more. This is known as exponential growth.

Setup:

Agar plates must be prepared ahead of time, wrapped tightly in plastic, and placed in cold storage. They need to be sterile for the experiment to be accurate. A contaminated plate will grow unknown microbes that will interfere with the results.

To make the agar plates use four 500mL Erlenmeyer flasks. Fill each flask with 10g LB Broth (powder form), 8g Agar (powder form) and 400mL of deionized water. Mix these solutions just enough to get the powder from the top into the solution (the powder will not dissolve completely). Place aluminum foil loosely over the flasks (it is important to leave the foil loose so that steam can escape). Autoclave the flasks on the fluid cycle for 20 minutes. Allow the flasks to cool in the autoclave for around one hour then remove the flasks, using the autoclave gloves, and cool the flasks in a 60 degree water bath. Once the flasks have cooled for about 20 minutes, pour just enough of the solution to cover the bottom of each Petri dish. This should make about 70 Petri dishes of agar. Make sure to cover the dishes immediately after pouring them to ensure sterility.

You want sterile swabs. If you cannot purchase individually wrapped swabs, you may dip some Q-tips in alcohol and let them dry.

Activities/procedure:

Four days is long enough to get good results for this experiment. After that, the plates begin to smell bad.

Explain to the students that we will be sampling the environment for microbes, and come up with some examples. Brainstorm some places that they think would have lots of bacteria, such as door knobs, the bottom of a shoe, the handle of a toilet, or your nose, mouth or skin. Think of some places that they are not sure of, like a hot hand railing or a freezer. Review what living things need in their environment to stay alive.

Take the class to a location with many different objects that could potentially host bacteria. This could be the classroom, an area outside, or another building. Give each student a clean cotton swab, and have them touch only one end to prevent contaminating the culture. Demonstrate how to swab something and then swab the plate. They should lightly swab the surface that they want to, and then gently run the swab back and forth over the agar without pushing down or breaking the surface of the agar.

As groups, let them explore the area to find a surface to test. Each student should rub the untouched end of his or her swab lightly over the area to be tested. Although the swab will not pick up any visible particles, it will collect bacteria. The students should rub the swab in a zigzag pattern, covering as much of the surface as possible. They will not see anything on the plate besides a light smear pattern. Make sure to tell them not to actually pick up pieces of stuff, like dirt, to smear in the plate. After the tray has been contaminated, close the lid and tape it shut with masking tape. Use minimal amounts of tape so as not to inhibit the view of the bacteria. On the tape, write the location of the culture. Leave the culture trays at room temperature overnight, away from direct sunlight but not in the dark.

As a demonstration and a control, swab one plate with a clean cotton swab. Tape the plate shut and label it. Chances are, it will grow some bacteria, since it is hard to find truly sterile cotton swabs. Explain that the purpose of a control in an experiment is to find out what will happen without introducing an outside variable (in this case, the introduction of different sources of bacteria).

Each day, give the students time to observe the growth of their bacteria. Have them draw pictures of the bacteria and compare their bacteria to those of the other students. Compare the growth of the control to see if there might have been some bacteria already contaminating the plate or the swab. Many different type of cultures may start to form as different types of microbes and fungi start to reproduce.

Extension:

Have some students put a drop of antibacterial ointment (such as Neosporin) on their plates. Nothing will grow around these drops.

Discussion:

• What are the three things that make us sick? (Viruses, bacteria, and parasites)

o Discuss what viruses, bacteria and parasites do and how they are different.

• Are all bacteria bad? (No. Not all of them make us sick. In fact, some are necessary for life)

o Discuss the functions of bacteria in the body and the environment.

• Where did the most bacteria grow? (Answers will vary. Swabs from the body, especially the mouth, grow very well. Other more obvious places, such as the toilet, may also grow well)

• Where did the least bacteria grow? (Sometimes the answer to this may be surprising. Sometime, toilet handles or doorknobs may have been sprayed with disinfectant, and will grow very little culture. Sometimes places that are exposed to direct sunlight, will have very little growth at all -- handrails and leaves have produced very little in the past)

• What caused these differences? (Perhaps different environmental conditions, especially extreme heat, or cleaning products)

Vocabulary:

• Agar

• Antibiotics

• Bacterium (Bacteria)

• Culture

• Contaminate

• Exponential Growth

• Fungus (Fungi)

• Germ

• Medium

• Microorganisms Or Microbes

• Parasite

• Pathogen

• Swab

• Virus

Biology

Feed the Yeast

Grades K-5 (with variations)

Overview:

This activity teaches students about yeast, a single-celled fungus. They learn yeast reproduce by budding and observe the yeast in dormant and active states.

Time: 15 minutes to set up, a 15 min break, and 10 min of observation.

Materials:

For the class:

• Warm (almost hot) tap water

For each group of 4-5:

• 2 very small cups (portion cups work well)

• 2 toothpicks

• 2 mL sugar

• 2 mL yeast

• 1 flask

For each student:

• Feed the Yeast activity sheet

• Magnifying glass

Background:

Yeast is a fungus, much like mushrooms and mold. However, yeast exists as single cells. It takes about 7 trillion cells of yeast to make a kilogram (3.2 trillion cells per pound). With the right combination of moisture, food, heat, and oxygen, these cells rapidly reproduce by a process known as budding. A bud, the beginning of a new cell, gradually forms on the surface of the parent cell. Buds are smaller than parent cells and may or may not break off once matured. In this fashion, whole chains of cells can be formed. A new cell develops in about 30 minutes, given the ideal conditions.

Yeast cells feed on sugars and multiply rapidly. They change sugars into alcohol and carbon dioxide when they are living and growing. Carbon dioxide bubbles form and are trapped below the surface, causing the yeast to expand. Yeast also produces spores. These spores can withstand normally unfavorable conditions. In this dormant state, yeast can survive for long periods without water or food, and at extreme temperatures.

Setup:

Each team will need two small cups: 1 mL of yeast in the first and 1 mL of yeast plus 2 mL of sugar in the second. Pour a small amount of very warm water into each group’s flask. Yeast works best when the water is nearly hot. Provide prepared cups, a flask of warm water, and two toothpicks for each group and magnifying glasses for each student.

Activities/procedure:

First, have the students make observations of the dry yeast. What does it look like under the magnifying glass? (Like little pellets) How does it feel in between your fingers? (Grainy) How does it smell? (Some say like bread or peanut butter)

Have the students add 15 mL of warm water to the cup containing just yeast, and then use a toothpick to stir the contents. It will start to foam up slightly, and the texture will change. Have the kids predict what they think will happen when they add water to the cup with sugar and yeast. Have the students then add 15 mL of warm water to the sugar and yeast cup, and then stir it using the second toothpick.

At this point, the mixture will have to sit for a few minutes for the yeast to rise (about 15 min works well). The sugar mixture will rise much more that the mixture without sugar. Observe the yeast and record observations on the activity sheet.

The contents of the cups will have to be taken out quickly, or you will end up with bread in a cup, and it gets difficult to clean up!

Discussion:

Discuss the yeast’s reproductive process of budding. Explain the needs of all living things to live and grow (water, food, air, sun).

Questions to ask after testing first cup:

• What did the yeast look like before you added water? (Small grains/pellets)

• What do you think will happen when you add water to the cup containing sugar and yeast? (It will grow/rise)

Questions to ask after testing second cup:

• What happened? (the yeast and sugar bubbled and grew. It smelled like baking bread)

• How can you explain the different results in the two cups? (the sugar provided food that the yeast needed in order to reproduce and grow)

• What did the yeast need in order to reproduce? (food, water and heat)

• Yeast is a fungus like mushrooms and mold. What does yeast have in common with them? (it is not green, has no flowers, seeds, roots, leaves, or stems)

• How are they different? (yeast is microscopic and lacks the structural features of mushrooms and mold such as a stalk, hyphae, mycelia, cap, spore case, and gills)

• Tell students that mushroom and mold spores can remain dormant until the conditions are right.

• Then ask them: What evidence is there that the same is true for dried yeast cells? (as grains, the yeast remained dormant, but began to grow and reproduce when provided with moisture and food.)

Vocabulary:

• Budding

• Dormant

• Fungus (pl. fungi)

• Parent Cell

• Spore

• Yeast

Recources:

Fungi- Small Wonders. Delta Science Module- DSM II. 25-35.

Biology

Leaf Slide Show

Grades K-5 (with variations)

Overview:

Kids will pick leaves and put them into leaf slides. They will then have a “slide show” and will share their leaves with the group while making observations of the different types of leaves.

Time: 45 minutes

Materials:

For each student:

• A leaf slide: a letter-size file folder with a 4 in square hole cut in the middle of it so that a leaf can be pressed in the folder

Teaching/demo materials:

• A variety of leaves that show the different colors of chlorophyll and the different types of leaf veins.

Background:

Leaves come in many different shapes and sizes. Their main purpose is to collect light which drives photosynthesis and produces sugars which work to feed the tree. The more leaves there are, the more surface area there is to collect light.

Gas exchange also occurs in the leaves. The leaves take in carbon dioxide, and then release oxygen through a gas transfer process called transpiration.

The green color in leaves is caused by chlorophyll which are photosynthetic pigments found chiefly in the chloroplasts of plants. The chlorophyll ester appears dark green or blue-black, but as the leaf starts to die, it looses its green pigment first and some of the other chlorophyll pigments become visible. The leaves then start to take on the fall colors of red, orange and yellow.

Leaves transport water through a series of veins. Some leaves have a branched network of veins, while other leaves, such as a blade of grass, have veins that run parallel. When leaves loose water, they get hard and dried out (or desiccated) and are referred to as necrotic (dead tissue). Some leaves have a waxy coating to help reduce an excess loss of water.

[pic]

Branched veins Parallel veins

If a leaf is on a single stem, it is called a simple leaf. If there are many leaves on a single stem, it is called a complex leaf.

[pic]

Simple leaf Compound leaf

Setup:

Leaf slides must be made in advance by cutting a 4” square hole in the center of a closed letter-sized file folder.

Activities/procedure:

Take the students to an outdoor location. Seat them in a circle on the grass and pass them each a leaf slide.

Make picking rules:

• Get your leaders permission before picking your leaf.

• Choose a leaf (or a small branch of leaves) that is large enough to fit in your slide.

• Choose your leaf wisely. You may pick only one.

• No tasting!

• Everything picked is going to go back into nature. You can not take anything home.

• Only pick something where you can find more than ten of them in a square foot (or about the size of their notebooks). This will make picking a single flower against the rule.

• Only pick things at the bottom of a bush, not right in the middle.

• Pick carefully. Pinching a leaf off works a lot better than pulling on a branch.

Emphasize that the students should not usually pick things and that this is a special exception.

Give the students/group leaders some boundaries and a meeting time and place. Then have them go out and find their leaves.

When the students meet together as a group, tell them that we are now going to have a slide show! When the leader says “click” they will all pass in one direction around the circle. Have the kids hold up that hand, so they know which way to pass it. They will then hold their leaf up to the light, but not directly at the sun! Remind them that they should not have more than one slide in their hand at a time, and they need to wait for the leader to say “click” before they pass. The kids may also need to be reminded that they need to hold the slide very carefully as they pass it, so that the leaf will not fall out.

After the students have seen all of the leaves, lead a discussion. Have them then return the leaves back under the bushes, and turn the leaf slides into their leaders.

Extension:

Leaf Rubbings: Have each student take their leaves back to the classroom, put them under a piece of paper and rub a crayon over the leaf, leaving an impression of the leaf.

Discussion:

Discuss all of the different types of leaves that were found. Ask questions that address the biggest differences, such as:

• Why are the leaves different colors? (Some may be due to a different chlorophyll pigment that is present in a live leaf, while some color change will be a result of the dying leaf and loss of pigments.)

• Why are some leaves brown? (Some students may pick up a brown leaf, or the leader should have an example set aside. This is a good example of what happens after all of the pigment and water is gone and the leaf becomes necrotic.)

• Simple vs. compound leaves. How are they different? (Different shapes, more than one leaf, veins)

• How do these trees and plants reproduce? (trees and some plants- seeds, grass- runners, and ferns- spores)

• Did anyone notice veins in the leaves? What are these for? (Movement of water, like little straws. Some are branched, some parallel.)

Vocabulary:

• Carbon Dioxide

• Chlorophyll

• Compound Leaves

• Desiccated (Dried Out)

• Necrotic (Dead Tissue)

• Oxygen

• Photosynthesis

• Pigment

• Simple Leaves

• Surface Area

• Transpire

• Veins

Biology

M&M Resources

Grades K-5 (with variations)

Overview:

Students learn the importance of conserving natural resources by using M&M’s candy to represent different resources. When resources are not conserved, there are no more for those that come after you!

Time: 20 minutes

Materials:

For the class:

• 1- Large bag of M&M’s candy (1 bag is enough for up to 40 students)

• 1-3 Paper plates (about 1 for each 7 students)

For each student:

• 1 Paper cup

Background:

Natural resources that we use include water, solar energy, trees, air, coal, natural gas, and soil. Many of these resources are limited, so learning to conserve them is important. Since there are an unknown number of future generations, we must leave as many resources behind as possible by taking only what we need and learning to replace them with renewable resources. If we use up our resources faster than they can be replaced, there will not be enough for future generations. One Native American belief is that one should think about how their actions will affect the next seven generations.

Setup:

Set one or two paper plates on the ground and pour some M&M’s into them. Have enough clean paper cups for each student to have one. Put a couple of extra cups in each plate, so the kids can use them as a scoop and are not touching the candy.

Activities/procedure:

Have the students meet in a circle with their group leaders and divide them into about four generations (depending on the size of the class) and give each student a paper cup.

Make sure you tell them that they can not put these cups on their mouths.

Set the plate of M&M’s on the ground in front of the generations. Tell the class that it is a plate of natural resources, and assign a resource to each color of M&M’s. For example; Blue= water, brown=soil, orange=petroleum, yellow=sun, green=plants, red=animals. Tell the first generation to go ahead at take as many resources as they want.

Instate rules that they cannot touch the candy with their hands and any candy that hits the ground becomes wasted resources. (the candies need to be kept clean since they will later be returning them, but don’t let the kids know this!) Have a group leader in the first generation that encourages them to take a lot of M&Ms. This may well insight a riot, as the kids fill their cups with candy! After the first generation has as many as they want, there will be very few left. Now, let the second generation take as many as they want. The M&Ms should run out long before the last generation has a chance to get any. Have a discussion about what happened and how that made the later generations feel. Have the kids return their candies to the plates.

Next, try it again. This time, have another group start off. They will often take revenge and will make the same mistake by gobbling up all of the M&Ms without conserving any for later groups. Obviously, if this is going to be fair, the group needs to decide how they are going to divide the resources. Guide this discussion until the students come up with a solution such as taking one of each resource (color), or a similar idea. If they suggest taking a specific number, point out that they might not get some of every resource (but that may work the best for time). They will often agree that the best way to do it is for everyone to get a certain amount of candies (say, 5 each).

When the class has come to a conclusion of how they can get some of every resource and still leave some for future generations, have them try again. Once all the generations have taken candy they should all have similar amounts. However, many groups will leave no more on the plate. What about the next generation, and the one after them? Hopefully, they will think of this and leave some on the plate at the end of the activity. Allow the students to eat their M&M’s. Often, we will give the kids a few extra M&Ms (dividing up the extras)

**Make sure none of the students have peanut allergies. Even the plain M&M’s can cause allergic reactions due to the peanut dust in the factory where they are made. If allergies in the class exist, Skittles can be substituted for M&M’s

Discussion:

• What happened when the first generations took as much as they wanted? (There was nothing/not enough left for the future generations)

• Did the second generation get as much as the first? (No)

• Did the later generations have any resources left at all? (No/not enough)

• How can you make sure the later generations have resources? (Only use what each generation needs, replenish any resources)

• Are there only [four] generations in the world? (No. There are many more than that)

• Will the generations that come next have any resources? (Not unless we reduce our use of resources)

• What is one way to save REAL resources for future generations? (Plant trees, only use what we need, recycle, reduce, reuse, etc)

Vocabulary:

• Coal

• Conserve

• Natural Gas

• Natural Resources

• Non-Renewable Resources

• Renewable Resources

• Soil

• Solar Energy

• Water

Biology

Make a Habitat

Grades K-5 (with variations)

Overview: Before kids can do any scientific observations involving living things, they need to

Time: 45 minutes

Materials:

For the class:

• Various art supplies of your choosing, if so desired. (We used sidewalk chalk, when weather permitted.)

For each student group:

• Make a Habitat activity sheet (One per group with younger kids would work best, older kids can each have one)

Teaching/demo materials:

• Fish tank

Extension: Sidewalk Habitat

• Sidewalk chalk

Background:

A living organism needs food, water, air, and shelter from intolerable weather conditions. Without any one of these things, an organism will not survive.

A habitat is the place or environment where a plant or animal naturally or normally lives and grows. It is the place where something is commonly found.

An artificial habitat is a housing for a controlled physical environment in which an organism can live under surrounding inhospitable conditions (such as a fish tank) An artificial environment for a human may be a biosphere under the sea or on the moon.

Setup:

If you decide to go an artistic route with this lesson, the art supplies need to be gathered. If you are going to do this using only found objects in nature, an area should be scouted out to make sure there will be enough things on the ground to gather up. This can be difficult in a well landscaped area, such as a school.

Activities/procedure:

The idea of this lesson is to have the kids think about the things that all living organisms need to survive and then to use their imagination to build a habitat for their group’s organism, where each of these four things are represented.

The first thing to do as a group is to vote on what organism you will build a habitat for. For this, use the “Make a Habitat” worksheet. After the group has thought about the things that their organism needs, they are ready to build an imaginary habitat for it. There are a few different ways to accomplish this and you can use a variety of objects to “build” your habitat. Go with what you think would work best for the group and with the weather. Have fun, and let the kid’s imagination run with ideas.

Ideas include:

• Build a diorama- like display in an unused fish tank.

• Build an environment under a table using construction paper and found objects

• Draw a mural on the chalk board or sidewalk using colored chalk

• Take a nature walk and gather objects that can be used to build a habitat in a clearing

OR a combination of the above can work well. Adding leaves, grass and other found objects to a sidewalk chalk habitat makes a great display.

After each group has had a chance to build their habitat, have them practice what they are going to say to the rest of the group about their habitat. Then meet back together in a group and take a quick tour of each habitat. We often make a train by putting hands on shoulders for our tour. Move quickly, so the kids don’t get bored. Maybe have each group share one thing that they really liked about their habitat.

If you have time left over, have each group bring one thing to one big class habitat. Chances are, in the end, all of the four necessary things for survival will not be represented. Have the kids come up with what is missing and how to remedy it.

Extension:

Sidewalk Habitat: Provide sidewalk chalk for the kids and allow them to draw larger scale versions of their habitats on the sidewalk.

Discussion:

• What is a habitat for a human? (buildings, even clothing, help us adapt within our habitat)

• What have we done to build our habitats around us? (houses with heating, pluming, windows for fresh air)

• What is the habitat for the animals around us? (Answers may vary. Houses, alleys, parks, forests, yards, etc)

• What happens when two organisms compete for the same habitat? (often, one of them have to find a new place to live OR they find a way to live together)

• What happens when an organism’s habitat gets destroyed? (it has to find a new place to live or it is not able to survive)

Vocabulary:

• Air

• Food

• Habitat

• Organism

• Shelter

• Water

Biology

Observing Fish and Insect Parts

Grades K-5 (with variations)

Overview: Through a fun art activity, students will learn the different parts of fish and of insects.

Time: 30 minutes

Materials:

For the class:

• Crayons/ markers/ colored pencils

For each student:

• Observing Fish Parts and/or Observing Insect Parts worksheets

Teaching/demo materials:

• Answer key for Observing Fish Parts or Observing Insect Parts worksheets

• A classroom aquarium and/or an insect display (such as Indian Walking Sticks)

Background:

Other animals have parts that do many of the same things that human parts do.

Fish (from Tetra Aquademics ):

Fins: Fins are used for swimming and sometimes for protection. Some fins are paired and others unpaired. The paired fins are the pectoral and pelvic fins. The unpaired fins are the dorsal, caudal (tail) and anal fins. The way the fins are used varies among different groups of fish. Most fish use their tails to move through the water and their other fins to steer with. Fins are most bony fish are flexible and supported by visible spines and rays. The shape, location and size of a fish's fins are closely linked with its way of life.

Pectoral Fins: The paired pectoral fins are usually responsible for turning, although they can be used for other functions such as tasting, touching, support and as a source of power for swimming.

Pelvic Fins: Paired pelvic fins add stability and are used for slowing some bony fishes.

Dorsal Fin: This may be a single fin or be separated into several fins. In most bony fishes, the dorsal fin is used for sudden direction changes and acts as a "keel" to keep the fish stable in the water.

Caudal (or tail) Fin: This is responsible for propulsion in most bony fishes.

Anal Fin: The anal fin adds stability.

Tails: The shape of the tail can be an indicator of how fast a fish usually swims.

Crescent-shaped: Fish with crescent-shaped tails are fast swimmers and constantly on the move.

Forked: Fish with forked tails are also fast swimmers, though they may not swim fast all of the time. The deeper the fork, the faster the fish can swim.

Rounded: Fish with a rounded or flattened tail are generally slow moving, but are capable of short, accurate bursts of speed.

Eyes: Fish are visual predators. Many nocturnal fish have large eyes to help them feed at night. Fish such as sharks have pupils that dilate and constrict, and some sharks also have an eyelid that closes from the bottom upward. Bony fish eyes lack both of these characteristics.

Mouths: The position of a fish's mouth gives a general indication of where it feeds in the water column. In an aquarium, fish with up-pointing mouths like hatchetfish primarily feed on the food flakes that float or hang near the water surface. Some fish with mouths on the underside of their head, like the catfish, feed on the bottom. A catfish would be very beneficial to the Aquademics® aquarium because, as a bottom-feeder, it helps eliminate unused food buildup by eating the food particles that sink to the lower levels of the tank.

The shape and size of a fish's mouth can also tell you what it eats. Since tropical fish in an aquarium have small mouths, Tetra has developed a variety of small fish food flakes, granules and tablets for daily feedings.

Gills: Fish, like most organisms, need oxygen to survive. The oxygen that fish "breathe" is dissolved in the water. The oxygen enters the water surface by diffusion or in the water from plants as a byproduct of photosynthesis. Water enters the fish's mouth, moves across the gills and passes out the gill slits or operculum. The gills are made up of a bony or cartilaginous arch supporting a large number of paired gill filaments. Numerous small projections with very thin membranes on each filament are the sites of gas exchange (oxygen to carbon dioxide). Beneath the thin membrane is a network of blood vessels. Oxygen diffuses from the water through the membrane into the blood and carbon dioxide diffuses outward.

Insects (from ):

The Indian Walkingstick (also called the laboratory stick insect, Carausius morosus) is a long, slow-moving, plant-eating insect from India. There are almost 3,000 species of stick insects (Order Phasmatodea) in the world; all are nocturnal (most active at night) herbivores (plant-eaters).

Camouflage:

The walkingstick is well-camouflaged in its environment, since it looks like a twig (plant mimicry). Plant mimicry also occurs in its eggs; the eggs have hard shells and look much like tiny brown seeds.

Anatomy:

Like all insects, the Walkingsticks have a three-part body (head, thorax and abdomen), six jointed legs, two pairs of wings, and two antennae. Their body is covered with a hard exoskeleton. Walkingsticks breathe through a series of holes called spiracles; they are located along the sides of the body. Indian Walkingsticks are brown or green. The body is long (up to 8 cm for females, 6 cm for males) and thin (with a diameter of about 5 mm).

Metamorphosis:

Indian Walkingsticks are often parthenogenetic; females can lay unfertilized eggs that hatch into females who can also lay unfertilized eggs. Walkingsticks undergo simple (or incomplete) metamorphosis; eggs hatch into nymphs, which look like little adults without wings or reproductive organs. Nymphs molt about 6 times as they grow to bcome adults. Indian Walkingsticks have a life span of about 18 months.

Setup:

Gather art materials and make copies of the worksheets and answer keys in advance. Classroom displays with insects and/or fish are nice to have.

Activities/procedure:

Ask students to think about the functions of different parts of their own bodies. Sketch the outline of a tropical fish and an insect on the board, point out the basic parts and explain the purpose for each part as simply as possible. Encourage students to compare the fish's body parts and purposes to their own. Ask students some of the discussion questions, and then give them several minutes to identify the parts of a fish and/or an insect.

Discussion:

• What body parts do I use to see, hear, taste, touch and smell?

• What body parts do I use to move around?

• How do I move backward? (Let students demonstrate)

• How do I move side to side? (Let students demonstrate)

Vocabulary:

Abdomen

Anal Fin

Antennae

Caudal Fin

Compound eye

Eye

Dorsal Fin

Gill Slit

Head

Jointed leg

Mandibles (jaws)

Mouth

Pectoral Fin

Pelvic Fin

Thorax

References:





Biology

Nature’s Tea

Grades K-5 (with variations)

Overview:

This activity teaches students to appreciate nature by enjoying the scents of different combinations of plants.

Time: 25 minutes

Materials:

For the class:

• Variety of hardy plants

For each student:

• 1 Paper cup

Setup:

Find an out-door location with a variety of plants, trees and bushes. Make sure it is an area where the students are allowed to pick pieces off the plants without causing damage.

Background:

Sometimes science involves observation. In this lesson, students will make observations and they will use their sense of smell. Since plants are alive, studying them is one thing a biologist may do. Every plant is different and has different characteristics, such as smell. Combining different plants can create unique scents.

Activities/procedure:

Take the students to an outdoor location. Seat them in a circle on the grass and pass them each a paper cup.

Make picking rules:

• Do not put the cups on your mouth or you will loose your cup

• No tasting!

• Everything picked is going to go back into nature. You can not take anything home.

• Only pick something where they can find more than ten of them in a square foot (or about the size of their notebooks). This will make picking a single flower against the rule.

• Only pick things at the bottom of a bush, not right in the middle.

• Pick carefully. Pinching a leaf off works a lot better than pulling on a branch.

Emphasize that the students should not usually pick things and that this is a special exception. Tell them to find different plants, flowers, bark, etc. that might smell good to put in their cups.

Once the students have collected their plants to make their “tea”, call them back to the circle. Tell them that you are now going to share. Chose a direction to pass the cups, and have the kids raise that hand (left vs. right is a challenge). Make a rule that you can only have one cup at a time. When the leader says “pass” pass once and do not pass until the leader says so. Have them pass the cups around and smell each one (go quickly). After they are done, lead a discussion. Kids may be surprise at how many different smells their were and how some of them smelled like other things (lemon and pumpkin are common) Have them put the contents of the cups back in the bushes and return the cups to the leaders.

Discussion:

• What did the cups smell like? (Answers will vary)

• Did they all smell different? (Yes)

• Did anything surprise you? (Answers will vary)

Vocabulary:

• Nature

• Scent

Biology

Web of Life

Grades K-5 (with variations)

Overview:

Students learn how organisms and resources within an ecosystem are interrelated, and how when one is affected, others are as well.

Time: 20 min

Materials:

For the class:

• Large ball of yarn (tangles less than string and easier for kids to hold)

For each student:

• A nametag with the names of things in an ecosystem

Teaching/demo materials:

• Pictures of different organisms

• A Forest Food Web

Background:

The following is information relating to a similar activity written by:

©2002, President and Fellows of Harvard College, Understandings of Consequence Project (see references for website)

Subject Matter

• An ecosystem is a combination of living things in a community and the non-living things in the physical environment surrounding them (biotic and abiotic factors).

• Different organisms in ecosystems need certain things to survive, such as water, air, soil, food and sun.

• Organisms in an ecosystem can be put into three categories: producers, consumers and decomposers.

• There is interconnectedness in an ecosystem, and changes in one population in an ecosystem may cause changes in other populations in that ecosystem.

• Energy from the sun is transferred in a domino-like pattern.

Causality

• Causes can have direct and indirect effects.

• Causes can have far-reaching effects.

• A seemingly small precipitating cause can have extensive effects.

• In a system, isolated effects are uncommon.

• Effects often appear to propagate in domino-like patterns including ones that branch or radiate out.

The activities in this section are designed to help students understand the connectedness within ecosystems. An ecosystem is a community of different types of living things (organisms) and their physical environment (including sunlight, rocks, soil, water, hills, holes, etc.) The organisms in an ecosystem interact just as people interact in a school. Each organism has a role (or "niche") in the ecosystem. Each living thing in the ecosystem depends on other living things.

The sun plays a critical role in the ecosystem. It provides the energy for all life on Earth and thus all Earth's ecosystems. Plants convert sunlight to make their own food, which they use to support their own lives. When animals eat plants, they eat this "ready-made" food, formed from energy originally provided by the sun. The sun's energy is thus passed along to them. In this way, the sun's energy fuels every living thing. Plants are called producers because they produce or make their own food. Animals are called consumers because they consume (eat) food but do not produce it on their own. There are different kinds of consumers: those that eat only plants are called primary consumers or herbivores; those that eat only animals are called carnivores; and those that eat both plants and animals are called omnivores.

Some organisms in the ecosystem are called decomposers. They decompose or break down dead matter by digesting dead plants and animals. (In this sense, they are also consumers.) They break down dead matter into basic materials, which are recycled into the soil and become nutrients that can be used by plants and some other living things. Therefore, they play an essential role in the ecosystems.

Food Chains

Students are usually taught about ecosystem feeding relationships in terms of food chains. For instance, they are shown a food chain beginning with the sun or green plants and extending to secondary consumers (those consumers that eat the organisms that eat green plants). Food chains address one of the difficulties that elementary students tend to have when reasoning about ecosystem relationships. Students usually focus on simple linear or direct effects (one thing makes another happen). For instance, students realize that the green plants are important to the organisms that eat green plants. However, students often don't detect indirect connections. It is common for students to reason that the green plants are not important to the things that don't eat them even if those things eat things that eat green plants. Learning about food chains helps them to see the domino-like pattern and to move beyond simple direct effects to indirect effects.

Food Webs and Domino Causality

The activities in this section introduce domino causality to help students move beyond noticing only direct effects. Domino causal models describe how, like dominoes falling, effects can in turn cause other effects. The dominoes can fall in different types of extended patterns, for instance branching or radiating. For branching patterns, events closer to the "stem" have a greater effect on the rest of the branch than ones that are further away. In radiating patterns, one event can have many direct and indirect effects.

Domino causal models provide a way to visualize more extended patterns of cause and effect. They enable students to organize more information about the system. These patterns are some of the easiest causal patterns for students to learn. However, without direct teaching, many students will not learn to recognize them.

The activities in this section also introduce food webs. Like food chains, food webs illustrate the domino-like patterns of indirect effects. Learning only about food chains can reinforce a short sighted, linear view of how ecosystem members affect each other. Students are likely to miss more extended domino-like patterns, such as branching and radiating ones. A food web shows the broader energy transfer relationships within an ecosystem. It can help in predicting how changes in a population will affect other living things.

[pic]

It is important to realize that focusing solely on domino patterns is not the answer to students' difficulties either. An overemphasis on domino patterns can make it harder to detect other types of patterns such as cyclic or two-way patterns. The trick is to help students learn different types of causal patterns (simple linear, domino, cyclic, and two-way) and when each type applies.

There are at least three other concepts that give students difficulty in understanding feeding relationships in ecosystems: The direction of the arrows, overemphasizing connectedness, and reasoning about populations vs. individuals.

The Direction of the Arrows

The arrows in a food chain or food web go from the thing that is being eaten to the thing that eats it to show the transfer of energy. When students try to reason about food webs, they often reverse the direction of the arrows to show what eats what. They reason about "active", more easily visualized aspects of what happens (this eats this) rather than "passive", less easily visualized aspects (this gains energy from this). Students can be encouraged to use the arrows to "point to the mouth of the thing that eats it" to help them construct the arrows in the right direction.

Overemphasizing Connectedness

It is possible to take the connectedness message too far. There is enough redundancy and flexibility in food webs that not all seemingly harmful or disruptive events adversely affect food web members. Once students understand the basic idea of connectedness, this caveat can be introduced.

Reasoning about Populations vs. Individuals

Young children find it hard to reason about populations as opposed to individuals. When creating a food chain, they think of the predator as eating the particular animal as prey, rather than each animal representing a population of animals. It is important to reinforce the understanding that the food web shows how populations of organisms interact. Even though one organism is pictured or talked about, the whole population is being represented.

Setup:

Each student will need a nametag with an organism or resource on them. You will need a representation of the following:

Sun, (Soil and Water also make interesting scenarios) Green Plants , Insects , Mammals including large carnivores (wolf, cougar), grazing mammals (deer, cow), rodents (rabbits, mice), Amphibians, Fish, Birds including birds of prey (i.e. Owls, Hawks), Snakes and other reptiles, and Decomposers (Fungi, Earthworms).

Try to make up enough different types of organisms that it will represent a food chain. You will need to have a leader be the sun, to start off the activity.

Activities/procedure:

Have the children stand in a large circle in a large outdoor area. Each of them should have a “web of life” nametag. Try to position the kids so that the different types of nametags evenly spread out (i.e.- don’t put all of the plants together in a group). The more spread out they are, to more it will take the shape of a web. Talk about not pulling on the string and listening carefully during the activity. Start off with the sun holding the ball of string. Then, move on to the producers, which are the plants. Have each kid with a plant nametag hold on to the string, and try to zigzag across the circle to create a web effect. Then move on to those who eat plants (insects and herbivores), those who eat them (carnivores, predators) and then those who take care of those things when they die (decomposers), all the while discussing the effects one thing has to another. In the end, you will end up with a very effective web.

Now come up with a scenario were any one of the organisms or resources is destroyed/depleted. Examples: a factory runs heated water or pollution into a stream, killing water organisms; the soil gets polluted and the soil bugs die; a species is hunted into extinction; the sun is blocked by smog, etc. Then one at a time, follow the scenario through the food chain, and have the kids drop their string one at a time, as they are no longer able to survive. The web becomes very slack very quickly. Eventually, everyone (except the sun in many situations) will have dropped their string. It is quickly apparent that everything around us is interconnected. Lead a discussion about what they have learned. Make sure the kids don’t run through or pull on the yarn tangle, and then carefully roll up the ball of yarn.

Discussion:

• Is everything living connected in some way? Give some examples. (Yes, answers will vary)

• How can we do our part to make sure that our “web of life” doesn’t collapse? (Protect endangered species)

Vocabulary:

• Consumers

• Decomposers

• Domino Patterns

• Ecosystem

• Herbivores

• Omnivores

• Predators

• Primary Consumers

• Producers

References:

President and Fellows of Harvard College, Understandings of Consequence Project



Biology

Worksheet Index

Worksheet:

Bean Growth

Dissecting Fungi

Dissecting Beans and Seeds

Environmental Swab Plate Growth

Feed the Yeast

Make a Habitat

Magnify Your World!

Observing Fish Parts

Observing Ant Parts

Observing Walking Stick Parts

Web of Life

Page:

45

46

48

50

52

53

54

55

57

59

61

SKIES

Biology

Bean Growth Stickers (Copy onto transfer paper)

Group 1

Control: Water/Light/Food/Air

Variable 1: No Water/Light/Food/Air

Variable 2: Water/No Light/Food/Air

Variable 3: Water/Light/No Food/Air

Variable 4: Water/Light/Food/No Air

Group 2

Control: Water/Light/Food/Air

Variable 1: No Water/Light/Food/Air

Variable 2: Water/No Light/Food/Air

Variable 3: Water/Light/No Food/Air

Variable 4: Water/Light/Food/No Air

Group 3

Control: Water/Light/Food/Air

Variable 1: No Water/Light/Food/Air

Variable 2: Water/No Light/Food/Air

Variable 3: Water/Light/No Food/Air

Variable 4: Water/Light/Food/No Air

Group 4

Control: Water/Light/Food/Air

Variable 1: No Water/Light/Food/Air

Variable 2: Water/No Light/Food/Air

Variable 3: Water/Light/No Food/Air

Variable 4: Water/Light/Food/No Air

SKIES

Biology

Dissecting Fungi Key

SKIES

Biology

Dissecting Fungi

SKIES

Biology

Dissecting Plants and Seeds Key

SKIES

Biology

Dissecting Plants and Seeds

SKIES

Biology

Environmental Swab Plate Growth Data Sheet

Surface Swabbed:

Day 2, Tuesday Notes:

Day 3, Wednesday: Notes:

[pic]

Day 4, Thursday: Notes:

Day 5, Friday: Notes:

[pic]

SKIES

Biology

Feed the Yeast

Yeast

Yeast and Sugar

What did you learn about yeast from this experiment?

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SKIES

Biology

Make a Habitat

Animal:

My animal likes to live near:

My animal needs:

My animal lives in:

My animal eats:

Other special things about my animal:

SKIES

Biology

Magnify Your World!

SKIES

Biology

Observing Fish Parts Key

SKIES

Biology

Observing Fish Parts

SKIES

Biology

Observing Ant Parts Key

SKIES

Biology

Observing Ant Parts

SKIES

Biology

Observing Walking Stick Parts Key

SKIES

Biology

Observing Walking Stick Parts

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[pic]

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