Prep for Teachers
Before teaching this lesson, make certain that all of your Web sites are bookmarked on all of the computers in your classroom, and that all of the necessary links are still valid and running. CUE your videotape to the first segment you are going to use in the Learning Activity, at the visual cue of a green tree snake slithering along a tree branch as the narrator says, "But where did snakes come from? The answer is rather surprising."
Make sure that each lab station has all of the necessary components already in place for the start of the lesson. Place all handouts and pencils needed for this lesson on each of the students' desks before class begins.
When using media, provide students with a FOCUS FOR MEDIA INTERACTION, a specific task to complete and/or information to identify during or after viewing of video segments, Web sites, or other multimedia elements.
Explain to the class that for many of us, snakes are considered an evil and reviled creature of nature. Yet, for the most part they play an important role in our ecosystem. Ask them what is the first thing that comes to mind when they hear the word snake, see a snake, or think about snakes. On a clear overhead sheet record your class's answers to the questions you posed. (Student reactions will vary.)
Tell the student that they are now going to take a little pre-lesson quiz to test their knowledge about snakes. Take your students to the following Web site: Easy Snake Quiz at www.snakequiz.com/easytest/correct.html. Provide your students with their first FOCUS FOR MEDIA INTERACTION, asking your students to take the quiz to see what they already know about snakes. (The site consists of ten questions of a varying nature about snakes. Each participant is graded on their responses and is afforded the opportunity to view their correct and incorrect responses. Each question is also given a brief explanation in regards to the correct response. To see the questions and correct responses for each question see Appendix A at the end of this lesson.)
After your students have completed the Easy Snake Quiz and shown you the results of their efforts, explain to your class that they are going to be learning about snakes. Ask the class if any of them know the record for the world's longest Anaconda, and record your students' responses on the overhead. Tell your students that they will find out the answer to this question and many more later on in the lesson.
Insert NATURE: Snakes - Deadly Companions into your VCR.
Provide your students with a FOCUS FOR MEDIA INTERACTION, asking your students if they know how snakes evolved into the species they are today. Allow your students a few seconds to write down their prediction on the FOCUS FOR MEDIA INTERACTION Worksheet. When they hear the answer to the question posed, they are to raise their hands. PLAY the videotape. PAUSE the videotape when the narrator says, "But there were legless lizards and it was from these that snakes evolved." Allow time for your students to check their predictions against the answer the video provided. Discuss with your students if they know of any other species of animal that evolved and adapted to better suit its environment. Refer back to the segment just viewed to check for student comprehension. (Lizards. It is hard to believe that snakes have anything to do with animals like the Komodo dragon. Primitive reptiles evolved into Turtles and all other reptiles. During the evolution of primitive reptiles, there were no signs of snakes. But there were legless lizards and it was from these that snakes evolved.)
Provide your students with a FOCUS FOR MEDIA INTERACTION, asking your students if they know the four main categories of reptiles and how many different types of snakes there are today. Again, allow a few seconds for your students to write down their predictions on the FOCUS FOR MEDIA INTERACTION Worksheet. PLAY the videotape. PAUSE the videotape at the visual cue of the four main categories of reptiles after the narrator says, "For a 110 million years they have been living side by side with other reptiles. Today, there are more than two and a half thousand different species of snake." Discuss with your students the various types of species of reptiles that can be found in the four main categories while allowing time for them CHECK their predictions against the answers the video provided. (The four main categories of reptiles are: turtles, snakes, lizards, and crocodiles. There are more than 2,500 different species of snake.)
Discuss with your student the following: Snakes evolved from legless lizards. Obviously legless lizards once had legs, so they must have used their legs to move around their surroundings. If both legless lizards and snakes have no legs, how do they move along the ground? Allow time for your students to respond to your question. Write your students' responses down on the overhead. Each time a student gives a description, have them demonstrate their response using a plastic Slinky or themselves. Allow a few moments for your students to write down their classmates' predictions on their FOCUS FOR MEDIA INTERACTION Worksheet. Provide your students with the next FOCUS FOR MEDIA INTERACTION, asking them to view the following segment to check their predictions as they relate to a snake's movement. PLAY the videotape. PAUSE the videotape at the visual cue of the sea snake diving back down towards the bottom of the sea after the narrator says, "Even this sea snake must interrupt its hunting for a breath of air at the surface." Discuss with your students the various styles of locomotion that snakes use to move. (Snakes move in various manners. Some slither using the serpentine method, others use the rectilinear style, some use the serpentine wave. Tree snakes can make portions of their bodies rigid like a ladder and sea snakes act like an eel in the water. All snakes can swim.)
Using the plastic slinkys, the students can demonstrate each style of movement. Discuss with them how each style varies and have them look at which styles of locomotion expend a great deal of energy, which ones do not, which styles allow a snake to move quicker or slower. Again, allow a few minutes for your students to check their classmates' predictions against those seen in the video and to write down notes from your discussion.
Ask your students if they know how snakes see, hear, and smell both during the daytime and at night. Again, allow your students time to write down their prediction on their FOCUS FOR MEDIA INTERACTION Worksheet. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to watch the next video segment and raise their hands when they can describe the snake's different senses. PLAY the videotape. PAUSE the videotape at the visual cue of the snake attacking the mouse in infrared. Allow your students time to check their predictions against the information they viewed in the video. Discuss with your students similarities and differences between human beings and snakes. Talk to your class about how humans can feel and hear vibrations, how we can sometimes not only smell odors but that at times if we breathe through our mouths we can even taste them, discuss with your class how snakes have an advantage over us in regard to seeing at night. Use examples of how human beings with sight and hearing loss compensate for their loss by increasing their abilities in other sensory areas. (Snakes can smell using their tongue, licking the air looking for the scent of their prey. Snakes use their bodies to sense ground vibrations. Snakes have sensory bits on both sides of their head that can detect their prey through body heat or infrared heat detection.)
- Snakes evolved from legless lizards.
- There are four main categories of reptiles
- There are over 2,500 different species of snakes.
- Snakes move in various ways
S-Wave (Serpentine Wave)
- Tree Snakes can make portions of their bodies rigid like a ladder
- Sea Snakes swim like eels. (In fact all snakes can swim)
- Snakes smell using their tongues
- Snakes use their whole bodies to hear through ground vibrations
- Snakes have two infrared heat sensing pits that aid in their seeing their prey at night.
FAST FORWARD the videotape to the visual cue of the Australian cane fields at night with a full moon above it. Ask your students why they think snakes need venom. Allow your students time to record their prediction on their FOCUS FOR MEDIA INTERACTION Worksheet. Have your students share their ideas with their classmates to stimulate a discussion about the students' individual predictions. Have your students role play their predictions if necessary. An example would be to strike and disabled prey larger than them. Place one student on a chair and have the second student explain how the snake could possibly attack this type of prey. Discuss with your students how animals of varying sizes are able to thrive and survive despite of a lack in physical size. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to identify why snakes need venom. PLAY the videotape. PAUSE at the visual cue of the snake consuming the rat after it has attacked it as the narrator says, "Breaking down cells in its body." Allow your students time to write down their answers on their FOCUS FOR MEDIA INTERACTION Worksheet. Again, have your students' role play and or discuss the ability of snakes to strike their prey, injecting venom and either killing or disabling their prey. Discuss with your students other examples of how animals and insects use distinct physical characteristics to hunt and subdue their prey. (Since a snake's head houses all of its sensory equipment, the head is very vulnerable to injury when it strikes at its prey. Venom gives a snake two huge advantages. First, it helps kill or paralyze its prey quickly, thereby ensuring that the snake is not injured, since only one bite is needed. Second, it helps breakdown the snake's prey, making it easier to digest.)
FAST FORWARD the videotape to the visual cue of the snake wrangler Donald Striden removing a lid from a snake cage. Ask your students if they know how a snake delivers its venom to its prey. Provide your students with their next FOCUS FOR MEDIA INTERACTION, asking them to listen to and record the various ways in which a snake can deliver its venom to its prey. PLAY the videotape. PAUSE the video after Donald Striden says, "a snake is never without its venom." Allow your students a few moments to record their answer. Review with your class how the Puff Adder injects its venom into its prey.
FAST FORWARD the videotape to the visual cue of the nurse caring for a man whose leg has been bitten by a snake. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to listen and record the various methods in which a snake delivers its venom without being harmed during the attack. PLAY the videotape. PAUSE the videotape after Donald Striden says, "One would die of asphyxiation. You literally can't breathe and one could die from a heart attack." Allow your students time to write down their answers on their FOCUS FOR MEDIA INTERACTION Worksheet. (The Boomslang Snake is a back-fanged snake, and it has the ability to open its jaw 120 degrees, allowing it to strike large prey and deliver its venom much like the Puff Adder. The Spotted Cobra has fixed fangs, and their fangs are both small and erect at the front of their mouth. Even the smallest scratch from these fangs can kill a human being.)
FAST FORWARD the videotape to the visual cue of a flock of birds in a marsh. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to listen for and record the name of the largest snake in the world, where is it found, how it capture its prey. PLAY the videotape. PAUSE the videotape after Donald Striden releases the Constrictor Snake back into the bush. Allow your students time to write down their answers on their FOCUS FOR MEDIA INTERACTION Worksheet. (The Anaconda is the largest snake in the world. It is lives in South America (Venezuela). Constrictor Snakes attack their prey by lying in wait, then striking their prey and biting into it with hundreds of tiny sharp teeth. It then coils its body around the prey slowly, constricting or crushing it to death.)
FAST FORWARD the videotape to the visual cue of an African Egg-Eating Snake approaching an egg. Ask your students if they know how a snake can eat prey considerably larger than itself. Allow your students a few moments to write down their prediction on their FOCUS FOR MEDIA INTERACTION Worksheet. Ask your students to share their predictions with their classmates. Record these predictions on the overhead. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to identify how snakes can eat large prey. PLAY the videotape. PAUSE the videotape after the snake swallows the egg. Allow your students time to check their predictions and those of their classmates against the answer from the video. (All snakes can eat meals bigger than their heads. The snake simply opens its mouth as wide as possible, then special ligaments in their lower jaw expand, allowing them to eat their prey.)
Explain to your students that they are now armed with enough information to begin the next leg of their discovery about snakes. In the next part of this lesson, they will be broken up into groups to complete a Web scavenger hunt that will culminate with each group producing a short 3-to 5-minute video about snakes.
Web Scavenger Hunt -- Student Video
Per student (or group of four):
- 1 Scenario Sheet with directions
- 1 Pen/Pencil
- 1 computer with Internet connectivity with Windows 95 or higher, Internet Explorer 6.0/Netscape Navigator, Windows Media Player/Movie Maker, (or similar video editing software) and JAVA Script.
- Assorted Colors of Construction Paper
- Assorted Colors of Markers
- 36 Styrofoam/Paper cups
- 36 lids to match the cups
- 36 inches of heavy
The activity in the culminating activity section was adapted and rewritten by Robert Redmon from "Snakes Alive" written by Cynthia Matzat for Mrs. Mael's elementary science class.
Step 1: The Scenario
Explain to your students that Mrs. Tanis, their Life Science teacher, has a very famous uncle, the famous herpetologist Salazar "The Slink" Slithers. Slithers has just returned from one of his adventures and brought back a treasure to share with your class -- four baby snakes from around the world! While visiting your class, Slithers received an emergency phone call asking him to go help a remote South American village with an invasion of frogs. In a tizzy, he handed the snakes to Mrs. Tanis and asked that the snakes be taken care of until he returns from South America.
Your teacher, being the quick thinker that she is, immediately decided to put you to work. Your class has four new baby snakes to care for, and each one is a different kind! What will you feed them? What kind of habitats do they need? Most importantly, why would anyone want to save snakes? Are they actually important, useful animals?
Step 2: The Mission
Explain to your students that Mrs. Tanis decides to make this slippery situation an exciting event for the whole school. She wants the students to create a short video to share with the school that shows the school all that they have learned about these interesting reptiles. These videos should include:
As junior herpetologists and wildlife filmmakers, it will be the students' job to research one of the snakes and create a five to ten minute video presentation on the snake of their choosing. Remind students that their main goal is to find out if snakes are important, useful animals.
- Information about the life cycle of a snake
- Anatomy of a snake
- How snakes move on the ground, in the water, and in the trees
- How snakes survive in the wild as both predator and prey
- The adaptations snakes have made to survive all these years in various environments and habitats
- Myths and folklore behind snakes
Step 3: The Procedures
Explain to your students that Mrs. Tanis wants to make sure you know the meanings of some words related to snakes. When they create their videos, they will be required to use the correct terminology when discussing their chosen snakes.
Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to visit the Merriam-Webster Online Dictionary at www.m-w.com/home.htm, and define the terms found below. Students should be required to use these terms during the rest of this unit.
Snake Vocabulary: Reptile, Habitat, Cold-blooded, Lateral Undulation, Concertina, Rectilinear, Slide-pushing, Venom, Habitat, Predator, Scales, Vertebrate, Fangs, Receptors, Infrared, Shedding, Anti-venom, Coiled, Slithering, Herpetologist
The Life Cycle of a Snake
Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to visit the following Web sites and document their findings as they relate to the life cycle of a snake on their graphic organizer (see attached).
Natural Resources and Environmental Conservation
Pick a Snake
Students need to pick one of the four snakes that Dr. Salazar "The Slink" Slithers left with Mrs. Tanis.
Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to visit the following Web sites to learn more about their snake. Ask your students to answer the following questions:
Eduscapes: Specific Snakes
Animal Allsorts-The Reptile House
The Anatomy Section
Anatomy Of A Snake
Amphibian & Retile Index-Anatomy Of A Snake
Where does your snake live?
What is its habitat?
What is the life cycle of your snake?
What is the anatomical makeup of your snake?
What type of locomotion does your snake use to move along the ground, in the water, or in trees?
How does your snake survive in the wild as both predator and prey?
What adaptations have snakes made to survive all these years in various environments and habitats?
What types of myths and folklore are there about snakes?
Create a Model of Your Snake
Using the information they have obtained about their particular snake, students are to create a model of their snake for use in their video. Use the following steps to create a snake for demonstration purposes.
Step #1: Determine the type of locomotion your particular snake uses to travel.
Step #2: Using a pencil, punch a hole in the center of the base of each Styrofoam Cup and their lids.
Step #3: Cut a piece of thick rope, twine, string, or yarn about 36 inches long.
Step #4: Thread it through the holes in each Styrofoam cup and lid.
Step #5: Space the cups apart.
Step #6: Tie a large knot at both ends of the snake.
Step #7: Leave about 5 inches after the knot at the head of your snake for pulling it.
Step #8: Decorate your snake with markers and construction paper.
Step #9: Cut a diamond-shaped head out of construction paper, and glue to the first cup on your snake.
Saving the Snake: Fact or Fiction
As we already know many people fear snakes and probably think Mrs. Tanis and "The Slink" are foolish for wanting to save four baby snakes. Provide your students with a FOCUS FOR MEDIA INTERACTION, asking them to use the information they have learned so far about snakes and the following Web site to determine why snakes are important, useful animals and the role they play in our ecosystem: Snakes: Information for Missouri Homeowners at http://muextension.missouri.edu/xplor/agguides/wildlife/g09450.htm.
Students should include a section in their videos explaining to the viewer the role snakes play in the ecosystem.
On to the Video
Explain to your students now that they have done all of the background research, they will need to create their video presentations. Using the information that they have acquired during their Web scavenger hunt, they are to create a video informing their peers about the ecological benefits of snakes. Students should include in their videos the following information about snakes:
Sources of food and shelter
Manner of reproduction
Where they evolved from
Interesting facts and myths about snakes
While making sure to include the model, they have constructed in order to demonstrate how their snake moves and any other information that they deem necessary to convey their message.
Explain to your students that they will be evaluated using a Rubric System. (Please see Appendix B for an example of a grading rubric that you can use with this lesson to grade your students' efforts in both the Web scavenger hunt and their videos.)
SCIENCE/LANGUAGE ARTS/ FINE ARTS
As seen in the video, snakes live in a variety of habitats around the world, and alongside a variety of other life forms. Students are often unclear about what animals live in the same habitat. To correct the common misconception that lions and tigers live in the same areas, have students do research to create a display on a map that shows the location of big cats around the world. They might include leopards, cheetahs, and panthers, in addition to lions and tigers. Students can also find out facts about each environment to display on the map.
LANGUAGE ARTS AND READING
Have your students read Snakes by Eric S. Grace (San Francisco: Sierra Club Books for Children, 1994.) to learn about snakes, the most common reptile. The snake lives on almost every continent, in almost every climate, on both land and in water. People fear snakes, but did you know that more than 75 percent of the world's snakes are not poisonous?
Have your students use the Internet to locate organizations that support wildlife, marine life, and habitat conservation. Have your students learn how these organizations work to protect wildlife and to analyze their efforts based on what they have learned about snakes.
Have your students create a one-page Web site based on the facts that they uncovered during their research. Have them tie in snippets from their video as an interactive segment.
LANGUAGE ARTS AND SOCIAL SCIENCES
Have your students research snake symbolism in ancient civilizations and specific cultures. Students are required to give an oral presentation on the civilization/culture they researched and the role that the snake played in it.
- If possible, visit a local zoo that has a reptile house or nature conservation center that deals with reptiles. Students complete a field quest to complete based upon the reptiles that each organization has on site. Many of these organizations have an educational branch that have such activities available for visiting teachers and their students.
- Check with your state's Department of Fish and Wildlife to see if they have a program that brings indigenous live reptiles to the classroom if you are unable to visit a zoo or nature center.
- Invite a fashion designer to speak to your student about the use of reptile skin in fashion design. What makes people more acceptable of using a snake's, lizard's, or crocodile's skin for apparel over that of an animal with fur?
- Visit a local hospital or doctor's office to see exactly how snakebites are treated.
- Invite a herpetologist to speak to your students about the various snakes that are indigenous to your area and what methods they use to control the population if necessary, as well as how do they collect a snake's venom for creating anti venom serums.