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At-Academy Activity: Snakes and Lizards Structure and Function Hunt

Abstract

Through this scavenger hunt, students will practice connecting the physical characteristics of lizards or snakes with their apparent functions by observing and drawing in detail examples of snakes and lizards throughout the Academy.

Objectives

Through this scavenger hunt, students will:

  1. observe and draw in detail examples of snakes and lizards throughout the Academy.
  2. practice connecting the physical characteristics of lizards or snakes with their apparent functions. 

Materials

  • Snakes and Lizards Structure and Function Hunt (one per student)
  • pencils

Vocabulary

  • adaptation: a structure or behavior that increases an organism’s chance of surviving and reproducing in a particular environment
  • ectothermic: refers to an organism whose body temperature varies according to ambient external temperatures, i.e. cold-blooded
  • reptile: any cold-blooded vertebrate of the Class Reptilia including snakes, lizards, tortoises, turtles, alligators, crocodiles .  This Class includes the Orders:
    • Squamata: snakes, lizards, and worm lizards
    • Crocodilia: crocodiles, alligators, and caimans
    • Testudines: turtles and tortoises
    • Sphenodontia: tuatara – there are 2 species of tuatara, and they most closely resemble (and are most closely related to) lizards 
  • squamate: an animal in the Order Squamata that includes the legged and legless lizards, including snakes

Activity

Preparation

  1. Print out the Snakes and Lizards Structure and Function Hunt for each student. 
  2. Go over the scavenger hunt questions with your adult chaperones ahead of time and make sure they are familiar with the activity and vocabulary. 

Introduction

Snakes and lizards are reptiles.  Crocodiles, alligators, turtles and tortoises are also reptiles, but today we are only going to focus on a group within reptiles called the squamates, which include lizards and snakes.  There are over 8,000 different kinds of lizards and snakes, and they are very diverse in where they live, what they look like, how they move and what they eat.

  • Go over the questions on the scavenger hunt with your students and make sure they understand what they will be doing.  Point out that they can choose the squamates on which to focus. 

Procedure

  1. Divide students into their chaperone groups.  You may wish for groups to start in different areas of the Academy.  This activity is designed so that students can choose the animals on which they want to focus.  Plenty of squamates can be found in the Rainforest and the Aquarium.  There are also squamates on display in African Hall, Altered State: Climate Change in California, and Islands of Evolution. 
  2. Allow time for students to explore, observe, and answer the questions on the scavenger hunt. All of the squamates on this hunt were on exhibit in the Academy as of March 2011.

 Wrap-Up

Discuss the different squamates students chose to draw and describe.  Ask students to share examples of the different structures and the functions they found that help squamates survive.  If students want to research their chosen organisms more in depth, they can visit the Naturalist Center on Level 3, which features books, computers, and helpful staff.

References

  • American Museum of Natural History. (2006). Lizards & Snakes: Alive! Educator’s Guide www.amnh.org/lizards

California Content Standards

Grade Three

Life Sciences

  • 3a. Students know plants and animals have structures that serve different functions in growth, survival, and reproduction.
  • 3b. Students know examples of diverse life forms in different environments, such as oceans, deserts, tundra, forests, grasslands, and wetlands.

Grade Four

Investigation and Experimentation

  • 6a. Differentiate observation from inference (interpretation) and know scientists’ explanations come partly from what they observe and partly from how they interpret their observations.

Grade Five

Investigation and Experimentation

  • 6a. Differentiate observation from inference (interpretation) and know scientists’ explanations come partly from what they observe and partly from how they interpret their observations.

 

Background

What is a reptile?

Reptiles are vertebrates that belong to the Class Reptilia.  They are cold blooded, or ectothermic, which means their body temperature is not regulated by internal mechanisms. For humans, our normal body temperature is approximately 98.6 degrees Fahrenheit. But in reptiles, their internal temperature is dependent on the temperature of their surroundings.  This is why you might see a snake or lizard sunning itself on a rock.

  • All reptiles have three-chambered hearts, except crocodiles, which have four-chambered hearts (2 atria, 2 ventricles), like mammals and birds. Reptiles have well-developed lungs from birth and breathe air. Most of them have two lungs, except some snakes which have a single lung.
  • Scales and scutes make up the outer layer of their skin, which is dry and has high levels of keratin, to help protect the body and prevent water loss through the skin.  Most reptiles that have two sets of paired limbs have five clawed toes on each foot. In some reptiles, like snakes and worm lizards, the legs are absent.
  • Reptiles were the first animals with amniotic eggs that are laid on land and not in water. Their eggs have leathery protective shells and membranes that allow oxygen and other gases to pass through. Not all reptiles lay eggs; some give birth to live young from eggs hatched inside the body of the mother.
  • Reptiles have keen sense organs which help them find food and escape predators. Eyes are one of the most important sense organ and in most reptiles, they are located at the front of the head for binocular vision.

The focus of this activity is on a particular group of reptiles called squamates (pronounced skwah-mates).

What is a squamate?

Squamata means “scaly” in Latin.  Squamates include lizards, worm lizards, and snakes, which are sometimes called limbless lizards. This group of reptiles is one of the most successful among vertebrates.  There are 8,000 known species of squamates and they live in diverse habitats including rivers, lakes, seas, treetops, deserts and mountain ranges. Like other reptiles, squamates are cold-blooded and cannot generate body heat on their own, so cold temperatures are a limiting factor of where they can survive.

From fossil evidence, we know the first squamates appeared over 200 million years ago, most likely as small predators that lived on the ground.  Over time, squamates have evolved unique adaptations that allow them to survive in a variety of diverse habitats.  For example, while many squamates have well-developed limbs some do not.  The absence of limbs in squamates such as snakes, may allow them to easily navigate narrow underground tunnels and burrows. Why might it be an advantage to live underground?  Many squamates live in underground burrows to escape predators, help regulate their body temperature by avoiding intense heat during the day and cold temperatures at night, and have a safe place in which to lay their eggs.

Geckos and chameleons are lizards that have evolved special adaptations for life in the trees. Geckos’ toe pads are covered with millions of tiny hairs (setae) that allow them to climb vertical surfaces and even cling upside-down! Scientists are still trying to fully understand exactly how geckos accomplish this. Chameleons’ feet are highly modified for grasping tree branches.

 

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