Teacher Workshop

· "Energy comes to us from the sun in the form of sunlight, it is in the food we eat, and it sustains life."

· "Persons, places, and things have energy, but we observe only the effects of energy when something is happening – only when energy is being transferred from one place to another or transformed from one form to another."

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· "…there is more energy stored in the molecules in food than there is in the reaction products after the food is digested. The energy difference is what sustains life."

· Digestion of food in animals is the reverse process of plants making their food. In digestion, carbon combines with oxygen to make carbon dioxide. But when plants make food, they combine carbon dioxide with water to make a hydrocarbon compound such as sugar. This is photosynthesis and it requires an energy input, in this case the energy comes from the sun.

(Biology Concepts and Applications)

Page 712

· Energy transfers at each trophic level are so low that ecosystems have a hard time maintaining more than 4 consumer levels. In one aquatic ecosystem only 6 – 16% of the energy entering one trophic level becomes available for organisms at the next level.

· (my own thoughts) For animals, food is where they get their energy (if they are decomposers or detritivores decaying matter is their food and that is where they get their energy), for plants the sun is where they get their energy. There could be no energy in food without the energy of the sun being absorbed and turned into food in the plants.

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· Ecosystem: an array of organisms and their physical environment, interacting by a one-way flow of energy and a cycling of materials.

· Who are the players that use energy in the ecosystem:

1. Producers (autotrophs: self-feeders)— plants and other photosynthesizers get their energy from the sun and convert that energy to chemical compounds that allow them to build organic compounds from inorganic materials. For example, the sun is used to make sugar in the plant and that sugar is used to make the plant grow a flower, or stem, or leaves. Plants are the primary producers for the entire system ecosystem. They "produce" energy for everyone in the ecosystem by taking the suns energy to make food for themselves to grow and then produce food for the primary consumers. Everyone else in the ecosystem has to consume energy (food) from the plants, either directly or indirectly (such as a secondary consumer who eats a primary consumer who eats a producer), to obtain the energy they need to survive.

· Consumers (heterotrophs: not self-feeders)—Consumers feed on the tissues of other organisms. They obtain energy from the compounds the producers put together (for example, stems, leaves, fruit, flowers). There are several types of consumers: herbivores (eat only plants), carnivores (eat only animals), omnivores (eat both plants and animals), and parasites (extract energy from the living hosts they live on or in). There are also decomposers (fungi and bacteria that break down the remains or products or organisms) and detritivores (obtain energy from the decomposing particles of organic matter, such as crabs and earthworms).

· Producers (autotrophs) secure the nutrients as well as the energy for the entire ecosystem.

· "Energy cannot be recycled. Over time, most of the energy that the autotrophs fix is lost to the environment, mainly as metabolically generated heat."

Page 709

· Trophic Levels—A hierarchy of feeding relationships or "Who eats whom?" All the organisms at a particular trophic level are the same number of energy transfer steps away from some energy input into the ecosystem.

4^th Trophic Level—Tertiary Consumer (secondary carnivores, parasites or carnivores)

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3^rd Trophic Level—Secondary Consumer (primary carnivores)

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2^nd Trophic Level—Primary Consumer (herbivores, decomposers, detritivores)

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1^st Trophic Level—Primary Producers (plants, algae)

· People and decomposers may feed at many trophic levels.

· Food Webs—A straight-line sequence of who eats whom is called a food chain. However, one species may be linked to many food chains at once. So, to portray the feeding relationships in an ecosystem more accurately the food chains need to cross connect with one another. This is called a food web.

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· Major pathways of energy flow: "Plants fix only a small part of the energy from the sun. They store half of that in new tissues but lose the rest as metabolic heat. Other organisms tap into energy stored in plant tissues, remains, or wastes; and they, too, lose heat. All of these heat losses represent a one-way flow of energy out of the ecosystem."

· Two types of food webs: 1. Grazing food web (plants- herbivores- carnivores) and 2. Detrital food web (plants – decomposer- carnivores)

· "The amount of energy moving through food webs differs from one ecosystem to the next and often varies with the seasons."

Page 711

· Energy pyramid: shows energy loss at each trophic level. Energy pyramids have a large energy base (plants).

· Energy flows into food webs of ecosystems from an outside source, usually the sun. Energy leaves ecosystems mainly by losses of metabolic heat, which each organism generates.

· To measure heat transfer we can talk about how many kilocalories are transferred at each trophic level. A kilocalorie is 1,000 calories of heat energy (the amount required to raise the temperature of 1 kilogram of water 1° C) and it is used as the unit of measure for the caloric content of foods. An example of an energy pyramid is (page 712):

1,700,000 kilocalories from the sun (1,679,190 kilocalories lost)

Producers only use 20,810 kilocalories

Herbivores only use 3,368 kilocalories

Carnivores only use 383 kilocalories

Top Carnivores only use 21 kilocalories

(Decomposers and Detritivores use up all the energy lost through wastes at each trophic level: 5, 060 kilocalories)

If this were an energy pyramid it would be built with Producers—Herbivores—Carnivores—Top Carnivores(that have the least amount of energy available left to them)

Suggested Activitites

Plant Detectives

Description

Students will go on a hunt in the garden to look for clues that plants produce food for other animals.

Objective

Students will be able to recognize that animals eat plants and get energy from them.

Materials

Paper

Pencils or crayons

Cardboard Squares with a rubber band around them to hold the paper

Activity

Start this activity by asking: "What do plants use to make food for themselves so they can grow? Do we use the sun to make food in our bodies like plants? How do we get energy? Where do we get our food? Where do other animals get their food? Does this give them energy? What would happen if there were no plants?"

1. Explain that we are going to become plant detectives to find clues that animals eat plants. That includes all animals, the furry ones, insects, worms, etc….

2. Lead a discussion on what clues the students could look for in the garden and make a list of ideas so you have a reference for later.

3. Once the students have brainstormed a list have each child choose two things they want to look for and put them into small groups to explore the 8 garden beds outside.

4. When they are outside the students can use crayons or pencils and paper rubber banded to a square of cardboard (or use a clipboard if you have one) to draw the clues they find on the plants.

5. To conclude the activity head back inside and make a new list of all the things they saw and share their pictures. Did they see any animals actually eating the plants or things that come from the plants like a squirrel gathering nuts? Why do some animals need to eat plants? Does it give them energy? Do plants give us energy when we eat them?

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Plants Eat the Sun

Description

Play a game to determine that plants get their energy from the sun.

Objective

Students will be able to explain that plants use energy from the sun to make food for themselves so they can grow and become food for others (i.e.; seeds, fruit, leaves).

Materials

30 sun energy cards

30 leaf, seed or fruit cards

Activity

Start this activity with a discussion about who in the garden needs the sun’s energy (some answers may be: plants, humans, animals). Do plants need the suns energy? Why?

Plant Survival Game:

1. Place 30 sun energy cards on the floor. Have the students choose to be any kind of plant they want to be and find a seat on the floor amongst the sun cards.

2. The teacher will turn out the lights and explain that when it’s dark the plants can’t grow (meaning they have to sit completely frozen and not move); they need the sun to help them grow. The sun gives plants energy to make food for themselves and then plants have energy to grow and become food for animals.

3. When the teacher turns on the light the plants can grab all the sun cards that are close to them (if it gets too competitive you might want to assign a number of cards for them to grab). When the teacher turns off the light they have to freeze again. Play a few rounds by only turning on the light for a few seconds.

4. When they have gathered as many sun cards as they can reach they come up to the front of the room where all the plants can trade their sun cards to get leaf, seed, or fruit cards (1 sun card=1 leaf, seed, or fruit card). Ask the students, "What do we need to grow healthy and strong? What does the plant need? Why do the plants grow leaves, seeds, or fruit when they use their sun cards?"

5. At the end of the game lead a discussion with the students about what helped the plants to survive. "Could the plants grow in the darkness without energy from the sun? What else might plants need to survive that we didn’t have in our game? What does the plant do with the energy from the sun?"

Activity Variations

1. One variation on this activity is to have the students only receive leaf cards the first time they play. Then they play a few more rounds of gathering the sun cards and they trade them in for a seed or fruit card. Explain that the plants have grown tall and strong by growing leaves first and now they are able to grow food for other animals like seeds and fruits.

2. Another variation of this activity is to remove half the sun cards and tell them that winter is coming. Then, turn on the light but only for a second and see if they still were able to gather as many sun cards as before. Discuss how winter affects the growth of plants. Ask the students, "What do you see happening to plants in the winter? Is the sun’s energy giving plants enough heat and light to grow?"

3. A final variation on this activity is to have the students turn in their sun cards and build a whole plant together. The teacher could have the students each make giant plant parts and then they could use their sun cards to add plant parts such as the stem, leaves, flowers, fruit, etc….

Extension activity

Grow two radish plants in the classroom (radishes usually sprout within a week). Grow one on a sunny windowsill and grow one in a dark closet. Water both everyday so that the soil is moist. Discuss your results with the class after two weeks.

Sun Sense

Description

Hunt in the garden for energy by finding shady and sunny places and comparing the differences using your senses.

Objective

Students will be able to identify that the sun provides heat and light energy to the garden by using their senses.

Materials

The Garden or Playground

Your Body

A Sunny Day

Activity

Have students gather in the garden (or playground) and then explain that they are going to find energy in the garden. Something is making the garden grow and helping it to live. By playing this game we are going to find out who is giving the garden energy to survive. Before the game let them know that you can feel energy as heat and see it as light. Here are the rules for the game:

1. When the teacher says "Find Shade!" the students run to a shady spot and use their bodies to feel the temperature (hot or cool), and then their eyes (is it dark or light).

2. Then the teacher says, "Find Sun!" and the students all run to a sunny spot in the garden and use their bodies to feel the temperature (hot or cool) and then their eyes (is it

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There’s Food Chains in My Lunch

Description

Students will identify where all the food in their lunch comes from and determine if they have a food chain in their lunch.

Objective

Students will be able to define a food chain and explain that sun is the energy that powers a food chain.

Materials

Every Students Lunch

Activity

As students eat their lunch have them think about where they get their food. Does it come from an animal that eats other animals, or an animal that eats plants, or did it come from a plant? Lead the next part of the discussion by asking if they would have any food in their lunch without the sun’s energy shining down on earth? Who uses the sun’s energy to make food for themselves? Did you have any of these in your lunch?

Give them some new vocabulary words.

Food Chain: A relationship between animals and plants that tells us who eats who. It must contain plants, an animal that eats plants (herbivore), and may have another animal that eats the animal that eats plants.

Producer: All plants are producers because they produce food for others after using the sun to make their own food.

Consumer: All animals are consumers because they consume either plants or each other.

Knowing these new words. Ask the students if they have any producers or consumers in their lunch. Then lead them into a discussion of the possible food chains in their lunch. For each item they need to break it down into its ingredients and each food chain needs to have at least one producer and consumer. For example, crackers and cheese: the crackers are made from plants and we eat the crackers [this is a short food chain—sunč wheat (crackers)č us (humans)]; the cheese has a little bit longer food chain [sunč grassč cow (milk makes cheese)č humans]. To make the food chains more visual you can have them draw pictures of each thing (sun, grass, cow with cheese, and human) and then have them draw arrows from each picture to the thing that eats it.

After finishing lunch and making their food chains, lead a discussion with the students about where the food chains get all their energy to work. Ask the students, "In each food chain what was the first thing they had to have for the plants and animals to have energy to feed themselves? What was always the second thing in the food chain to produce food for animals? What was always the third thing in the food chain that consumed the plants? Do you remember the big names for plants and the animals that eat them? Can you explain what these names mean?

3. Lastly, the teacher says, "Find the teacher!" and have all the students gather back with the teacher.

4. Discuss their findings. "How did the sun make you feel? How did the shade make you feel? Was there light in the sunny spot or the shady spot? Where is the energy, or heat and light, coming from in the garden?"

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