Lesson Session – Weave a Food Web

Weave a Food Web

Subject – Science, Art

Grade Level – 4-6

Skills Used:

Predicting; Collecting, Recording and Interpreting Data; Identifying and Controlling Variables; Defining Operationally

Key Vocabulary:

Food Chain, Food Web

Lesson Time:

30 minutes

Conceptual Objective:

Students will understand that food chains overlap to form a web of multiple energy paths.

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Process Objective:

Students will create a model of a food web.

Materials

* construction paper
* markers
* scissors
* bulletin boards
* pushpins
* tape
* string
food web handout – click to download

Procedure

1. Introduce and explain the terms ‘food chain’ and ‘food web’ to students.

2. View, explain, and answer questions about an example food web.

3. Pass out handouts and explain how the information is set up on the chart.

4. Put children into groups of five, giving each group the necessary supplies.

5. Instruct children to draw and label all of the different woodland organisms listed. Also draw a picture of the sun. Cut out drawings and attach them to bulletin boards with pushpins. Leave space between the drawings.

6. Students should tape one end of the piece of string to any one of the drawings. Using the table, connect the other end of the string to the proper organism.

7. Students should draw and cut out an arrow, taping it on the string to indicate in which direction the energy is flowing.

8. Students should repeat these steps to connect all of the organisms.

9. Announce clean-up time, and display finished food webs around the room.

Lecture

What is the food chain?

Energy flows through an ecosystem as one animal eats another animal or plant. A food chain shows “who eats who” in an ecosystem.

For example:

An owl – eats a mouse who – eats a beetle who – eats leaves.

Each part of the food chain has a name:

Plants make (produce) their own food using water, sunlight and carbon dioxide (photosynthesis). Plant start the food chain. There are more plants than any other living thing because they are the bottom of the food chain. They provide the energy for everything else. They are the PRODUCERS.

The animals (insects, mice, chipmunks, squirrels, rabbits, deer) that mostly eat plants are called the herbivores. There are fewer herbivores than there are plants because each herbivore needs a lot of plant matter to live. Herbivores feed directly on the producers. They are the PRIMARY CONSUMERS.

Animals (spiders, birds, snakes) who eat the primary consumers (herbivores) are the SECONDARY CONSUMERS. There are fewer secondary consumers than there are primary consumers because each secondary consumers needs to eat a lot of primary consumers to live.

Animals (fox, coyotes, eagles, owls) who eat the 1st & 2nd consumers are carnivores (they eat meat). They are the TERTIARY CONSUMERS. There are fewer tertiary consumers than there are secondary consumers because each tertiary consumers needs to eat a lot of secondary consumers to live. Because there are fewer animals as you move up the food chain, it is really a food pyramid with the big carniores needing to eat the most and so being the rarest of the animal kingdom.

Because animals eat so many things, the food chain has many overlapping parts, so is really a FOOD WEB.

Last but not least, the DECOMPOSERS eat and so recycle dead animals and plants (mushrooms, fungi, insects, bacteria). They are then consumed themselves by other parts of the food web so nothing is wasted.

Something to think about:

In a food web, if an important animal is taken out, and there are no other animals to take its place, it can affect all the other animals in the food web. This animal is called a KEYSTONE SPECIES.

An example of this is the American alligator. Thirty years ago it was hunted so much in the everglades that it all but disappeared. What people didn’t realize was that the American alligator’s main food is the gar, a big everglade fish. The gar in turn eats a lot of the same fish people like (referred to as game fish).

When the American alligator disappeared, the gar (with no other predator) became very plentiful. All the extra gar ate all the game fish. Suddenly fisherman noticed that all the game fish had disappeared and there were gar everywhere.

The food web was out of balance. Once the American alligator was protected from hunting, its numbers rose quickly. In turn the number of gar decreased. Soon the game fish returned. The balance was restored.

Evaluation

1. Did students make and use a model that allowed them to make inferences about food chains? Assess the neatness and the accuracy of the food webs.

Troubleshooting

1. Students may argue about who will do what in the group. If this happens, the teacher should assign roles to students.

Lesson Session – Cold Blooded

Cold blooded

In this fun experiment, students learn what it means to be ectothermic (exothermic) or cold blooded.

Grades: 1-6

Background:

Being a reptile is hard work.

Humans are warm blooded (or endothermic.)   Our body temperature is at a constant temperature of 98.6 degrees, unless we are sick and have a fever.  We can wear clothing and shiver to raise our body temperature or sweat to cool our bodies.thermometer

Reptiles are cold blooded (or ectothermic)  and they cannot control their body temperature by wearing clothes or sweating.  Reptile body temperatures change according to the temperature of their surroundings. If it is 75 degrees outside, a snake will be 75 degrees inside its body. If it is 105 degrees outside, the reptile with be 105 degrees inside its body. Reptiles have a body temperature range that they must be at in order to survive.

Do you see many reptiles outside during the winter? Not if you live where it gets cold!  Reptiles have to hibernate during cold winters because it is too cold outside for their bodies to work properly. They cannot eat or move around when it is cold outside, so they go in to a deep sleep called hibernation.

During the warmer months of the year, a reptile has to keep within the temperature range it needs to survive. Reptiles must find a warm places to sit when they are cold, and find cooler places when they are hot. Have you ever stood in the sun when you are cold or moved to the shade when you are hot? That is what a reptile does all day.  Different species of reptiles have different temperature range requirements.

Set-up:

For this experiment you will need a number of thermometers. It is best for the students to split up into groups sharing a thermometer. To make things really fun, you can decorate each thermometer by gluing it to a picture of a reptile from a magazine glued to a note card or other heavy card stock.

About an hour before class, find an area that has many different features like rocks, grass, dirt, trees, and bushes. Find the lowest temperature in the area by putting thermometers in the shady areas. Then find areas with the highest temperature found on asphalt, rocks, or other hot surfaces in the sun.

Lay the thermometer down on an object – just like a reptile.   Wait at least two minutes before taking a reading.

Next, set up temperature ranges. They should be in five degree increments started at five degrees below your lowest recorded temperature and ending at five degrees above your highest recorded temperature.

Assign temperature ranges to the thermometer reptiles. If there are more temperature ranges than reptiles, space out the temperature ranges you assign.

Activity:

Pass out the reptile thermometers along with its assigned temperature range. Give the children ten minutes or so to find the best place to lay their thermometer reptile so that the thermometer reads within its assigned range. Remember it takes a minute for the thermometer to give a proper reading and it must be actually on something, reptiles cannot hover in the air.

Encourage the children to be creative and experiment where they put the thermometers. You may even have the children write down where they place the thermometer and what its reading is. Some students will not be able to find a spot that will keep the thermometer within their range. Others may have to keep moving their reptile thermometer to stay within their assigned range, just like a real reptile!

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Closure:

After ten minutes or whatever time limit you decide, have the children discuss the activity.

How do you think a reptile’s day would be different than a humans? What are advantages to being ectothermic? What are the disadvantages?

Scientific Names for Elementary School Students

We had a great Question from Sujan at our After School Class last week.

“What is the name of the lizard we met in class?”

Well Sujan, the Sudan Plated Lizard has TWO names!

The lizard we met is named Gerrhosaurus major, or “Gary” for short.  Why such a long name?

platedliz

All animals, rocks, plants, even types of clouds are given a special name called their “scientific name.”  This helps scientists put things in groups with things that are all alike.

For example:

Tree frogs that have sticky feet may be put in one group while frogs that have webbed feet and live in the water are put into another group.

They are grouped by the type of feet they have.

You can have fun doing an experiment in your own house!

Think of different ways you can group things in your house.  Some ideas may be.  Arranging things by color, size, or what it’s made of.

Choose a way to group things, then write down the different categories of groups.

Say you chose to group things by color.  Your categories will be different colors; red, blue, green, yellow..etc.

Then walk around your house and put objects in your house in its correct category.  (Yellow things go in the “Yellow” category.)  Write it down.

For extra fun, do this experiment with other people in your house.  Have them choose a different way to group things.  Compare your lists at the end!

You will find things that may be hard to put in one group.  (maybe it’s blue & yellow)  You can only put it inone, that means you have to decide!

It is lots of fun to be a scientist that classifies things!  They are called Taxonomists.