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BACKYARD CRITTERS
Grades K-3

Overview

The purpose of this lesson is to allow students to use the science process skills to increase their knowledge of common invertebrates by acquiring data through the senses; using laboratory materials; measuring; communicating through words, tables, graphs, and pictures; predicting, inferring, generalizing; controlling variables; conducting an investigation; and drawing conclusions. Students will collect various invertebrates from the school grounds or nearby parks; make careful observations of the animals they find both in the classroom and on the video; describe and compare methods of locomotion of each of the animals; conduct an investigation to find the speeds of each of the animals and have a race; and create a habitat where the animals will not need to move away to find a more suitable place. This lesson takes from 3-5 days.
ITV Series
Up Close and Natural #2: Animals Without Backbones
Up Close and Natural #15: Outside your Door
Learning Objectives
Students will be able to:
Materials
Per class:

Investigating Invertebrates
Per group of 4 students:

"Loco"-Motion
Per group of 4 students:

A Snail's Pace
Per group of 4 students:

They're Off!
Per group of 4 students:

Home Sweet Home
Per group of 4 students: Materials may vary, but may include such things as:

Pre-Viewing Activities
On a nice fall (or spring) day take the students out to a vacant lot, a flower bed, or some area where there are dead leaves, rocks, or logs on the ground. Take a plastic bucket or terrarium and trowels. The teacher should very gently lift rocks or logs or move leaves and look for your backyard critters. You will find a variety of inhabitants such as snails, slugs, isopods (pill bugs or sow bugs), millipedes, earwigs, ants, etc. In addition, look for worm castings (little piles of digested dirt) to indicate where earthworms might be present. All of these critters are called "invertebrates" by scientists. Vertebrae are the bones in your back. Animals who do not have backbones are called "invertebrates," which means "not vertebrates" or animals that do not have backbones. You will probably have to look in a variety of places to find enough invertebrates for the whole class. As you are collecting critters you should also collect some soil, leaf litter, twigs, flat rocks for hiding places, and whatever else is in the habitat where you find your specimen. You will need to set up a terrarium to house your critters and it should be as much like the place you found them as possible. You can also assign students to look in the flower beds in their backyard and bring in any critters they find. In addition, you may wish to purchase earthworms from a fishing bait store. They are very inexpensive (around $2.00 for about 20 worms). If you buy worms, try to get the small red worms which are sometimes called "jumping worms". These worms are more active than the larger nightcrawlers. Safety Note: Watch for fire ants. They have a painful sting. They are sometimes found under rocks and logs. If you move things gently you will not get stung. If disturbed, they can swarm on to a child and get into clothing and cause many painful bites. Also this collection is best done in an area with which you are familiar, perhaps the school grounds or a nearby park. Do not lift rocks in areas that are not often visited by people or in places where you see a hole. You do not want to come upon a snake. While that is not likely, it is always best to be cautious. When you return to the classroom have students classify the critters you brought back. Then tally the number of each set you found. Make a simple pictograph (a graph that uses pictures or symbols to represent data) using Lab Sheet 1 and sticker dots to show how many of each set you have. Use a different color for each type of critter. After you have collected enough critters for each group of 2-4 student to have at least 3 or 4 different critters, conduct a class discussion and make a language experience chart to find out what information the students already know about their critters. In a language experience chart, the teacher writes down exactly what the students say in their own words. Ask students how they found out the things they know. Many children may have already had some experience with at least some of the invertebrates you find. Others will have learned something about them as you collected. Point out that these are ways of acquiring data. Data is information scientists gather which is used to solve problems or answer questions. [Note: For kindergarten children you will probably need to work in pairs, perhaps even individually, in order for each child to be able to see the critters and so that they can explore. If you have students work individually, give each student only one critter. Allow them to then trade with someone who has a different critter so that they get to work with all of the different kinds you have found. Keep the terrarium with all of the critters in the science center so that students can come and explore it during center time. They will probably also check it spontaneously every morning when they arrive and throughout the day.] Give each group of 2-4 students a bag of critters and a small amount of leaf litter and soil. Groups should also have magnifiers, a ruler, and a petri dish. Students should place their critters in a petri dish and hold the dish up to get a better look of the critters from the underside. Have student make as many observations as possible about their critters. [See Note above for kindergarten students.] Students should describe the critters using both qualitative information (color, shape, etc.) and quantitative information (number of segments, legs, etc. and older children can measure the critters to give the size in centimeters). Allow each child to draw a picture of her/his critter(s). For older students you may want to have them organize their data using Lab Sheet 2. For kindergarten, it is best to allow the students to use blank paper to draw their critter(s). After about 10-15 minutes have students share their data with the class. Combine the class data so that you have complete descriptions of each of the critters and how they move. Add any new information to the language experience chart. List adaptations of each critter and the benefits those characteristics may have that help the animal live in your backyard. Add these to the language experience chart. Older students may wish to use the table on Lab Sheet 3 to organize their data. [Note: All groups may not have the same critters. However, it would be good if all groups could have at least two critters in common.]
Focus Viewing
To give a specific responsibility while viewing, have students watch the video segments very carefully to see how each type of critter moves. They will have magnified views of the earthworms in Up Close and Natural #15 and of the millipede and isopod in Up Close and Natural #2. Tell students that you want them to look for patterns in the way the invertebrates move. Look at the number of legs and the way the legs are moved.

Viewing Activities
Up Close and Natural #2 shows earthworms. Be sure that each child has an earthworm to observe in a petri dish or tray. Cue the video past the segments on the snake, frog, raccoon, caterpillar, and spider to the picture of two earthworms on the ground. With no sound, BEGIN the video. If you have "auto edit" on your VCR, switch it on and off and ADVANCE the video frame by frame. If not, PLAY the tape and PAUSE when the picture moves to Louise. You may want to REWIND and REPLAY this segment several times hitting PAUSE to stop and hitting PAUSE again to restart the video. (This segment is only 5 seconds long). Discuss with the students how the earthworms appear to be moving. Compare the pictures to the earthworms the students have in their petri dish or tray. With no sound, RESUME the video for 8 seconds for the picture of the earthworms in Louise's hand. Again, use auto edit to ADVANCE the video slowly to allow the students to discuss the movement they are observing or use play, then REIWND and REPLAY the segment. PAUSE when the close up of the worm and the word "bristles" comes on the screen. Discuss the bristles on the worm. Ask students how they think these would help the worm move. Add this information to the language experience chart. Have students run their fingers back and forth gently over the worm. Do they feel the stickery bristles? Continuing with no sound, RESUME the video and watch the worm digging in the soil. Talk about how the bristles are helping it move. PAUSE when the close up of the worm comes back up on the screen. [Note: When you preview you may want to listen to the sound to help you find the place to pause. It is where Louise says, "The rings show us where the earthworm's muscles are." Then a close up with the word muscles appears. You need to stop before the word comes up.] Discuss the segments of the worm. These segments are very muscular and help the worm to move. Put a piece of clear plastic laminating film on the TV screen. Using a water based pen for transparencies (so that if any gets on the screen it will wash off), draw the sides of the worm on the screen. Have students come one at a time and draw a line where one of the segments is. After several segments are drawn on the screen, have students look at their worms using magnifiers to help them see the segments. Remove the clear plastic film from the screen. Ask students to watch the next section of the video very carefully to see how the segments help the worm to move. RESUME the video. In the section where the worms are burrowing in the dirt, use the auto edit to ADVANCE the tape slowly or alternate PLAY and PAUSE to see the close up of the worm expanding and contracting his muscular segments. STOP the video where Louise is squatting next to the bucket. Ask the students to watch their worms move. [Hint: Have spray bottles of water available to squirt the worms to encourage them to move.] Now ask students if anyone can move like an earthworm. Allow students to get down on the floor and demonstrate how worms move. EJECT the Up Close and Natural #2 video and INSERT Up Close and Natural #15. Give each group of 2-4 students a petri dish with a millipede in it. With no sound, BEGIN the video where Louise is squatting on the path and the word "millipede" comes up. Have students watch how the millipede moves. PAUSE on the close up of the millipede. Ask how the millipede's body is similar to the earthworm's body. (long, segmented) How is it different? (legs) How many legs per segment? (2 on each side) Use auto edit or alternate PLAY and PAUSE to see the millipede's feet move. How are the legs moving? (in groups) How many legs move together? (4-6) Add any new information to the language experience chart. REWIND and REPLAY as needed for students to see how the millipede moves. PLAY the rest of the section of the video on the millipede. STOP when the millipede crawls under the leaf. Compare the millipede on the video with the living millipede in the petri dish. Ask students how we could act out how the millipede moves? Allow children to come up with a plan. For example several children can line up very close behind each other and hold around their waists, then try walking with all those legs, coordinating the movement of four legs on a side at a time. Let children express any ideas they have about the difficulties of manipulating so many legs. Ask students why the millipede may need so many legs. Accept all hypothesis and add them to the language experience chart. FAST FORWARD past where Louise turns over a log and looks at a centipede. PAUSE where she puts the isopod in the yellow bowl. Ask how the isopod is like the millipede. (segmented, numerous legs, antennae) How many segments does it have? (6 + the head) How many legs per segment? (1 on each side) PLAY the rest of the section of the video with the isopod. STOP where Louise is walking in the field. REWIND and REPLAY as many times as needed. How does the pill bug move? Is it more like the earthworm or the centipede? Add any new information to the language experience chart. What patterns did the students find in how the animals looked and how they moved from place to place?
Post-Viewing Activities
"Loco"- Motion Using what they have learned from the video and what they have observed of each critter, have students describe each type of movement and compare the ways the animals move. Add this to the language experience chart. How are the ways the critters move alike? How are they different? Classify the critters by their method of locomotion. You may need to mist the animals or put drops of water on them. If they start to dry out, it is difficult for them to move. They also need to remain damp in order to breathe easily.

A Snail's Pace Give students the large paper circles. Have them put one critter at a time in the middle of the circle. One student should time the critter to see how long it takes to reach the edge of the circle. One student should follow behind on its trail with a pencil to mark where it travels. When the critter reaches the edge of the circle, have students write down on Lab Sheet 5 the amount of time it took for the critter to make it from the center of the circle to the edge. Ask students to lay a string down on the pencil mark of the trail that the animal made and cut the string off at the end of the trail. The students should measure the string with a ruler to see how long it is. To figure the speed of the critter have students divide the distance (the length of the string) by the time it took to travel that distance (time to the edge of the circle). Repeat with each of the critters until the students have speeds for each. [Note: Some critters are very slow. At least one group should have a snail and quantify what a "snail's pace" is. Suggest that students time the earthworm last. They tend to move around in the middle of the circle and never seem to make it to the edge. Allow a maximum of 2-3 minutes and then just divide the distance traveled by the time even though they never finish their journey.] Combine all the results of the groups for each critter and find an average speed for each kind of critter. What is a "snail's pace"? Which critters travel at a "snail's pace"? [Note: For younger children, following the critter with a pencil is enough. (No pushing.) Have students lay the string on the pencil mark and cut the string. The students can compare the lengths of the strings to see which critter went the farthest distance. Which critter got to the edge of the circle fastest?]

They're Off! Have a race with your critters. Have students predict which critter will be the winner based on the data from "A Snail's Pace." Have students cut out the critters (see lab sheet attached) and paste them on a sheet in the order they predict the critters will finish. Put all of your critters in the middle of the circle under a clear cup. One student will watch the time. Have each of the students in the group watch a different critter.. (The critters may not necessarily all go in the same direction.) When a critter gets to the edge of the paper circle, the student watching that critter will call out "Finished!" Mark the time on Lab Sheet 7. Continue watching the other critters until all have "Finished." Younger children may not be able to time and record all of the critters. Simply let them note the order that the critters finish the race. Who won the race? Did the group's prediction come true? Why or why not? Have the students use their cut-outs of the pictures of each of the critters and write a number next to each to show the order in which they finished the race.

Home Sweet Home We have seen how fast the backyard critters can move. This was avoidance behavior. The animals were trying to get away. Now we want to find a way to make the animals feel safe enough to slow down. Have the students create a place where the animals do not need to run away. Make them a home where they will be comfortable. Students may use any of the materials provided. They do not have to use all of the materials. Have the students place the materials they have chosen in a tray (or a small box) and add the critters. Observe carefully for five minutes. What types of materials did the critters seem to prefer? Why do the students think they felt safe or comfortable with these materials? What behaviors did students see that leads them to this conclusion? Have older students draw a picture of their critters' home on Lab Sheet 8. Label the parts. Older students should write a report about what they found out from their investigation. Kindergarten students can draw a picture and dictate their ideas to the teacher to write on the back of their picture or write their report as a group and have the teacher add it to the language experience chart. For older children you may wish to try this additional investigation. Use a different color of water based marker for each of the critters. For five minutes watch your critters. Put a dot near each critter every 15 seconds. Describe the objects that each critter stays near. What conclusions can be drawn from their behavior?
Action Plan
Invite a gardener to come and visit the classroom and talk about how the backyard critters fit into the ecosystem. What are the benefits and problems caused by each? Invite the county agent to come and talk about how earthworms help develop the soil. Call the local bait store and see if there is a worm farm in your community. If so invite the farmer to bring in some of his "livestock." He can talk about how he raises earthworms and how worms are useful. Or if possible, go and visit the worm farm. You may even want to start your own worm farm.
Extensions
Science: Students may have questions about their critters and the way they live in their backyard. Encourage them to try to find the answers to their questions by setting up experiments. For example, what conditions does each of the critters prefer? (light/dark, wet/dry, soil/rocks, single living/ group living)
Science: Some students may have different types of isopods. Some are "pill" bugs and can roll into a ball. Others are "sow" bugs and are flatter and cannot roll into a ball. Have students compare these two types of isopods. Which of these is faster? Conduct some isopod races and see which type of isopod wins most often. How do their movements help them survive hungry birds?
Language Arts: Have students draw a picture that shows something they each remember about your trip to collect critters. Have students write a story to tell about their pictures. Or allow the students to tell you their stories so that you can write them down.
Art: Make worms with playdough, paint worm pictures with string (dip short lengths of string in paint, squiggle string onto paper, fold paper, and pull string out), draw, paint pictures, and glue collages about backyard critters. Language Arts: Have children dictate (or write) stories or poems about their pictures. Forms of poems can be very open. Example from Bryan age 5, "Worms, Skinny, brown, and wiggly, In the garden." Music: Make up a song using words the children tell you about how the critters move. Example: To the tune of "The Farmer in the Dell" "The worms are crawling out. They're crawling all about. They're creeping, inching, wiggling. They're crawling all about."

Math: Measure worms. Compare lengths of various worms. Place a worm on paper. Put a pencil mark at each end. Place the next worm beside these marks, and mark his length, etc. Find the longest, shortest, middle sized worms. You can sequence the worms by size if you cut your paper into strips and mark each worm on a separate strip. You can use a different color for each worm and use the strips to make a bar graph.
Worksheet
Click here to view the worksheet associated with this lesson.

Master Teacher: Sandra Johnson

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