Oregon Herpetology Curriculum

Tina Whitman

Introduction

     This series of lesson plans is intended to provide an introduction to amphibians and reptiles for students in grades four and five and includes background information, related student activities, a list of resources on amphibians and reptiles, and species lists for the state of Oregon. The background information provided for teachers is in not comprehensive but a instead offers a framework for further study and application in the classroom setting. There are many excellent resources for educators and students on amphibians and reptiles; a resource and reference list is included. The Oregon herpetology curriculum is meant to offer a starting off point and suggestions for hands and minds-on activities to help students have fun while learning about amphibians and reptiles.

Objectives

Section One: Biology and Classification

Section One: Background Information

     Reptiles and amphibians are often grouped together under the term 'herps' from herpetology, the branch of zoology that focuses on reptiles and amphibians. This term is derived from the word 'herpeton' which means 'crawling things.' This term is a relict from a period when naturalists believed that amphibians and reptiles were more closely related than they actually are. Early reptiles evolved from amphibians, so they are related, but in the same way that birds and mammals are related to early reptiles.


Characteristics of Amphibians

     Amphibians were the first group of vertebrates to become adapted to life on land and the term literally means 'double life'; referring to the aquatic and terrestrial stages typical to most amphibians. Amphibians are ectothermic, lack scales, and have glandular skin which secretes mucous and/or toxins. Amphibians lay masses of jelly coated eggs in wet environments, and most amphibians undergo metamorphosis. Amphibians in Oregon include salamanders and frogs (which includes toads). The first amphibians are believed to have existed 360 million years ago; today there are approximately 4000 species worldwide.


Characteristics of Reptiles

     The earliest reptiles were turtles, followed later by crocodilians then snakes and lizards. Birds and mammals also evolved in this period between turtles and the squamates (snakes and lizards). There are approximately 6000 species of reptiles worldwide today. Reptiles are ectothermic, have scales, a dry skin surface with no water or gas exchange occurring across this membrane and most reptiles lay shelled eggs on land. Reptiles do not undergo metamorphosis; when hatched the young look like little adults. Oregon reptiles include: turtles, snakes and lizards.


Salamanders

     Salamanders are carnivorous through their larval and adult stages. Most are secretive and nocturnal; primarily as a result of their need for a moist environment. Salamanders have a head, trunk and tail, with four limbs used for running and walking. Their tails are used for swimming, terrestrial balance and fat and energy storage. There are 19 species of salamanders in Oregon, the majority of which occur west of the Cascades.


Frogs and Toads

     The distinction that is commonly made between frogs and toads is not a scientific one but is based on the general observation that frogs have smooth moist skin, and toads have warty, drier skin. From this point frogs and toads will be collectively referred to as frogs. Frogs are herbivorous as tadpoles but become carnivorous after metamorphosis into their adult form. Frogs are the only amphibians that call, and the calling is primarily conducted by males. Types of frog calls include: mating, territorial, and distress. In general frogs are stout bodied creatures with protruded eyes, large hind limbs and no tail. There are 10 species of frogs in Oregon.


Turtles

     Turtles have a hardened shell which consists of the carapace (covers back), the plaston (over abdomen) and the bridge (connects the carapace and plastron). The shell of turtles is used as armor and the head, neck and limbs can all be drawn into the shell. Turtles lack teeth but have horny beaks similar to birds and feed primarily on vegetation, insects and worms. There are 2 native species of freshwater turtles in Oregon and 3 sea turtles which utilize the Pacific Ocean off our coast.


Lizards

     Lizards have a shape similar to amphibians with a head, trunk, four legs and a tail but the skin is thick and covered with protective but flexible scales. Lizards also have 5 claws on each foot which amphibians lack. Lizards have teeth, are mostly predaceous, and feed on insects, spiders, worms and other reptiles. Lizards have good vision including color and also have good senses of smell and hearing. There are 11 species of lizards in Oregon.


Snakes

     Snakes lack legs, movable eyelids and external ear openings and posses an elongated body plan with a flexible spine. Snakes have good close range vision and an excellent sense of smell aided by their forked tongues. Snakes can hear only at low frequencies and can also sense vibrations. Snakes are carnivores and eat their prey whole, utilizing their detachable jaw and small backward pointing teeth. There are 15 species of snakes in Oregon. Only one of our snakes is poisonous: the Western Rattlesnake.


Ectothermy

An ectotherm is an organism that depends on external sources for heating and cooling. Amphibians and reptiles, along with fish and all invertebrates are ectothermic and cannot internally maintain a constant body temperature. Birds and mammals are endothermic, and self-regulate their body temperatures. Ectotherms are often referred to as 'cold-blooded' which is not really the case, as most amphibians and reptiles maintain their body temperatures within a preferred range. To maintain their temperatures within this range, reptiles and amphibians practice thermoregulation.


Tactics of Thermoregulation


Metamorphosis

     Metamorphosis only occurs in amphibians and is the process by which young undergo a change to reach adult form. In amphibians, the typical life history trait is an aquatic larval stage followed by a terrestrial adult stage.

Section One: Student Activities

     In the following activities students will apply their knowledge of the differences and similarities among amphibians and reptiles and the major groups of amphibians and reptiles in Oregon. Through an interactive setting, students will gain a better understanding of the characteristic features that are used in classifying amphibians and reptiles.


"Who Am I?"

     For this activity you will need pictures of a variety of reptiles and amphibians pasted to cards which can be attached to students backs. You can complete this activity in either a large or small group setting; it may work well to begin in small groups and reconvene as students gain confidence. If they get really good you can time them to make it more challenging.

     Pin a picture of an animal on the back of a student making sure that they don't see the picture first. For the first level, have students ask questions with 'yes', 'no' and 'maybe' answers to their classmates to discover if their new identity is a reptile or an amphibian. Once they have reached this point, continue the questioning until they are able to identify themselves as a snake, lizard, turtle, frog, or salamander. Additional levels can easily be added to this game; for example if you are working on species identification with your students, the cards could portray individual species and the game would include more detailed features and descriptions.

"Creature Feature"

     A quieter activity that covers the same principles involves creating a concentration/memory game where groups of animals are matched to their major characteristics. Create the following individual cards with these labels on one side: amphibian, reptile, turtle, snake, lizard, frog, salamander, shelled eggs, undergo metamorphosis, thermoregulate, have scales, males have calls, have moist, slimy skin, smell with forked tongue, swallow food whole, have hard shell, can have tails that can break off and grow back, aquatic larval stage, permeable skin, can change color,..... There should be fewer cards with the broad categories of amphibian and reptile as they will match many features and multiple cards with snake, turtle, lizard, frog and salamander. These features are just some ideas, create your own set emphasizing the topics you covered in class. A related game could be also created with drawings or photographs of amphibians at different life stages and asks students to match larval forms with the mature adult to illustrate the concept of metamorphosis.

Section Two: Habitat

Section Two: Background Information

     Section two covers the general relationship between organism and habitat, based primarily on the basic biology of amphibians and reptiles outlined in section one. There are many complex features that allow amphibians and reptiles to survive in a wide range of habitats including high elevation alpine areas and hot arid desert regions. For this age level and activity students will be asked to think about the basics of reptile and amphibian biology and how it relates to habitat in general terms. Students should understand that the issues facing amphibians and reptiles in terms of habitat requirements are different as a result of the differences in their biology and life history. Amphibians are dependent on relatively stable aquatic resources for breeding sites as well as moist conditions in terrestrial habitats. Amphibian skin is excellent for the exchange of water and gases but is extremely poor at water conservation. Terrestrial amphibian habitats include riparian areas, pond margins, and forested areas that receive high precipitation such as high elevation areas on the east coast and throughout forests in the pacific northwest. Within these forested habitats amphibians are most likely to be found in the moister areas such as rotting logs, leaf litter, near seeps or underground in the soil. Reptiles are much better adapted to tolerate dry conditions, with thicker skin and other features such as the excretion of uric acid that aid in water conservation. In general, reptiles have a higher optimal body temperature than amphibians and require an environment with good solar access in terms of days and sites for thermoregulation. Reptiles are found more commonly in the low moisture open habitats, with plenty of sunny days and a variety of basking sites. Because they are ectothermic, amphibians and reptiles are able to lower their metabolic rates and many hibernate to avoid cold winters.

Section Two: Student Activities

     The activity for section two involves drawing and writing and asks students to make connections between the basic biology and life history characteristics of amphibians and reptiles and the kinds of habitats that they occupy. Discussion of habitats, type of animal and adaptive features should take place prior to this activity. Through the creation of a 'new' species of amphibian or reptile, complete with a suitable habitat, students will apply their understanding of the differences between amphibians and reptiles and of the relationships between different organisms and their habitat needs.

"Invent a New Amphibian or Reptile"

     Explain to students that they will be creating their own new species of amphibian or reptile. They are allowed to develop whatever they wish as long as the following criteria are met:

  1. It should be clear through their drawing or accompanying text whether the animal is a reptile or an amphibian (it must meet some of the major characteristics outlined in section one).
  2. The animal must come complete with a habitat that it can survive in. Make sure your students understand that they are free to create a brand new habitat type for their new species; the point isn't to stifle creativity but to make students think about the connections between 'creature features' and habitat. As long as the habitat provides what their species will require in terms of food, water, shelter, and thermoregulation to survive, anything goes!

Be sure to allow plenty of time for this activity, as well as time for students to share their creations with the rest of the class.

Section Three: Species Identification

Section Three: Background Information

     Section three focuses on the identification of local amphibians and reptiles and provides an excellent opportunity for a class field trip. The activities in this section are designed to provide students with an in-depth investigation of one (or a few), species of amphibians or reptiles. As all the activities culminate towards the production of a class field guide to local amphibians and reptiles, section three involves students in research, drawing, and writing, as well as engaging them in learning to identify amphibians and reptiles.

Section Three: Student Activities

     The activities in section three will provide an introduction to the identification of amphibians and reptiles, focusing on local species. Utilizing regional field guides students will create a their own class field guide to local species through a series of activities including research, illustration, identification and layout of the final product. If possible, a field trip with an amphibian and reptile expert or enthusiast should be planned to assist students with observation skills and provide an introduction to local species. If a field trip isn't possible, slides or regional field guides with color photos should be utilized to introduce students to the variety of amphibians and reptiles in their region and key characters used in identification. As a class, a list of local species of amphibians and reptiles should be generated; to save time, this list can be obtained from a local herpetology group, university, field guide, or other source. For Oregon classes there is a great web site with species lists, photographs and natural history information on amphibians and reptiles in Oregon. Find it at: http://darkwing.uoregon.edu/~titus/checklist.htm

"Class Field Guide to Local Amphibians and Reptiles"

Research

     Each student, or team of students will be assigned a species to investigate from the class list. The students will first conduct research on the basic biology, range, and habitat of their species. Most of this information should be available in field guides and the depth of study can be narrowed or expanded to match time or resource constraints. Students will also compile a short list of ways to identify their species. This information should be first be completed as a short report - portions of it will be used later as text for the class field guide.

Illustration

     A color drawing of each species should be created. If students are working in pairs they can share the duties or choose different perspectives (dorsal or ventral) and each complete a drawing. It helps at this point if students are provided with a paper size that matches the size that the drawing should ultimately be for inclusion in the field guide (4X6" or so if the guide will be on 8.5X11" paper). Notecards will work really well for this as they can be pasted directly into the guide.

Identification

     Once the drawings are all completed, hang or lay them out around the room. Post a blank sheet of paper next to each drawing labeled with the species name. Have students look at all the drawings and each write down one or two features that they would use to identify this species (such as central yellow stripe for the Western Toad) on the posted sheets. Use the most common answers, and any from field guides that you choose to include, as your short list of ways to identify the species in your class field guide.

Creating the Field Guide

     Each species will be allowed one to two pages in the class field guide; this will depend on the size you choose (8.5X11" is usually the easiest), and the size of your groups. The students will select information from their reports for the page to include: the species and common names, a brief description of the habitat where the species is likely to be found (within you local area), and any other brief but interesting information that they would like to include. These can be added to the illustrations and the short list of identifying characteristics that you have already created for each species and put together as your class field guide!

Glossary

(Definitions from Raven, R.H. and G.B. Johnson. 1986. Biology. Times Mirror, St. Louis)

Class Amphibia

     Salamanders, Frogs and Toads. Tetrapod, egg laying, ectothermic vertebrates that lack scales. Amphibians respire with gills as larvae, with lungs as adults, and in both stages via gas exchange across their skin. Amphibians were the first terrestrial vertebrates and they still depend on a most environment for at least a portion of their life cycles. The term amphibian means 'double-life' and refers to the typical life history of aquatic and terrestrial stages.

Class Reptilia

     The Reptiles: lizards, snakes, turtles and crocodiles. Tetrapod ectothermic vertebrates with a shelled egg. Reptiles have lungs and are covered in scales; most are fully terrestrial. Legs absent in snakes and some lizards.

Ectothermic

     An organism that regulates its body temperature by taking in heat from the environment or by giving it off to the environment. Often called cold-blooded, blood of ectotherms is not actually cold and is usually maintained within a taxa specific range.

Metamorphosis

     Process in which there is a marked change in form during postembryonic development. For example: tadpole to frog, or larval insect to adult. The term literally means 'change of life'.

Resources

(This is not a comprehensive list but a personal selection of resources)

Children's Books

Cole, J. 1980. A Frog's Body. William Morrow, New York

Ernst, C,H., and G.R. Zug. 1996. Snakes in ?: The Smithsonian Answer Book. Smithsonian Institution, Washington,      DC

Eyewitness Junior Series. 1993. A. Knopf. New York


Johnston, G. and J. Cutchins. 1988. Scaly Babies, Reptiles Growing Up. Morrow Junior Books, New York

Johnston, G. and J. Cutchins. 1991. Slippery Babies, Young Frogs, Toads, and Salamanders. Morrow Junior Books,      New York

Ricciuti, R. 1993. Reptiles. Our Living World. Blackbirch Press, Woodbridge Connecticut.

Ricciuti, R. 1993. Amphibians. Our Living World. Blackbirch press, Woodbridge Connecticut.

Simon, H. 1973. Snakes: The facts and the Folklore. Viking Press, New York

Winner, C. 1993. Salamanders. Carolrhoda Books, Minneapolis

Educator Resources

(these resources are from a list provided by the Smithsonian Herpetological Information Service, #93 1992)

Snakes!Snakes!Snakes! 1983. Nature Naturally, 7(1):1-6

Hands-on Herps. 1987. Science Activities, 24(4):27-30

Snaking Through Science.1983. Science Teacher, 50(4): 20-23

Lets Hear it for Herps! 1987. Naturescope, National Wildlife Federation 3(4): 1-69 The Class Menagerie: Using small      animals to enrich your science curriculum. 1987. Learning, 15(5): 64-66

Reviled and Revered: toads, turtles, snakes, salamanders, and other creepers and crawlers. 1992. Art to Zoo,      December 1992.

Reptiles and Amphibians: selected references for educators grades 2-12. Smithsonian Department of Vertebrate      Zoology, Washington, DC

Field Guides

Audubon Field Guide to North American Reptiles and Amphibians. A. Knopf, New York

Leonard, W.P., et al. 1993. Amphibians of Washington and Oregon. Seattle Audubon Society.

Stebbins, R.C. 1980. Western Reptiles and Amphibians. Houghton Mifflin, New York.

Storm, R.M., and W.P. Leonard. 1995. Reptiles of Washington and Oregon. Seattle Audubon Society.

General

Duellman, W.E. and L. Trueb. 1994. Biology of Amphibians. McGraw-Hill, New York.

Stebbins, R.C. and N.W. Cohen. 1995. A Natural History of Amphibians. Princeton University Press, New Jersey.

Zug, G.R. 1993. Herpetology: An introductory biology of amphibians and reptiles. Academic Press, New York.

Reptile and Amphibian Magazine (look at your local library or on the world wide web)

Species Lists for Oregon

(adapted from Leonard et al 1993 and Storm et al 1995)

Amphibians

Salamanders

Ambystoma tigrimun


Ambystoma gracile


Ambystoma macrodactylum


Dicamptodon copei


Dicamptodon tenebrosus


Rhyacotriton kezeri


Rhyacotriton variegatus


Rhyacotriton cascadae


Taricha granulosa


Plethodon dunni


Plethodon larselli


Plethodon vehiculum


Plethodon elongatus


Plethodon stormi


Ensatina eschscholtzii


Aneides ferreus


Aneides flavipunctatus


Batrachoseps wrighti Oregon


Frogs

Ascaphus truei


Scaphiopus intermontanus


Bufo boreas


Pseudacris regilla


Rana aurora


Rana cascadae


Rana pretiosa


Rana boylii


Rana pipiens


Rana catesbeiana


Rana clamitans


Reptiles

Turtles

Chrysemys picta


Clemmys marmorata


Lizards

Elgaria coerulea


Elgaria multicarinata


Crotaphytus bicinctores


Gambelia wislizenii


Phrynosoma douglassii


Phrynosoma platyrhinos


Sceloporus graciosus


Sceloporus occidentalis


Uta stansburiana


Eumeces skiltonianus


Cnemidophorus tigris


Snakes

Charina bottae


Coluber constrictor


Contia tenuis


Diadophis punctatus


Hypsiglena torquata


Lampropeltis getula


Lampropeltis zonata


Masticophis taeniatus


Pituophis catenifer


Sonora semiannulata


Thamnophis atratus


Thamnophis elegans


Thamnophis ordinoides


Thamnophis sirtalis


Crotalus viridis