Though the crocodile’s ancestry dates back 200 million years, the crocodile, as we know it today, first evolved about 80 million years ago. According to the fossil record, their body plan has changed little since, enabling them to outlive the dinosaurs and become the most advanced of all reptiles and the most successful freshwater predator.

There is no single secret to the crocodile’s success. With few natural predators, a permanent armor of bony plates covering most of its body and strong jaw muscles capable of crushing anything from bones to cast iron, the croc is an extremely tough and robust creature. A croc can survive even after serious injuries such as a torn off limbs or tail and has a powerful immune system that helps it survive for decades.

But its adaptations go beyond being hardy. One of the keys to its survival is something one might think of as primitive: cold-bloodedness. Like all reptiles, crocs are ectotherms, which means they must gather heat from their environment. Crocodiles have developed behaviors to control their body thermostat: they bask in the sun when cool and seek shade or water when hot. Ectotherms like crocs don’t need to eat regularly to warm their bodies, and so they save an enormous amount of energy that can be put to other use or stored for later. A croc’s metabolism is so evolved that its body uses and stores nearly the entirety of the food it consumes. This is one reason why larger crocodiles can go for over a year without eating a meal. In extreme situations, crocodiles appear to be able to shut down and live off their own tissue for a long period of time.

But most crocs eat much more often than that. In fact, the average croc eats about 50 full meals a year. When they feast, crocodiles are certainly not picky eaters. It’s said that a croc will feed on anything it can outswim or ambush and overpower. These reptiles have extraordinarily adaptable diets. Larger crocodiles will eat larger mammals and birds, but they’ll also eat fish and mollusks like snails. During difficult times, they will even scavenge for carrion. In fact, crocs will consume almost everything they encounter. And that means everything. A croc’s stomach is the most acidic of all vertebrates, allowing it to digest bones, horns, hooves, or shells. Nothing gets left behind in a crocodile’s dinner. In fact these hard objects are used as “gizzard stones” in the croc’s stomach to help grind coarse food.

While the crocodile’s diet may be undiscriminating, its social interactions are a bit more complicated. Crocs are more social than all other reptiles. Though they primarily lead solitary lives, they resort to group behavior for important activities such as hunting or raising hatchlings. Crocs don’t merely recognize one other, they form long-term relationships. They are hierarchical and communicate by means of vocalization, postures, chemical signals, even touch.

A crocodile’s brain is more complex than that of any other reptile. These powerful predators also have an excellent sense of smell and superior sound perception. Noting the crocís ability to learn to avoid dangerous situations, researchers have found that they have to modify their techniques when capturing crocs. It’s very hard to catch a croc twice with the same trick.

Crocodiles have demonstrated behavioral, physiological and structural adaptations that have allowed them to thrive for hundreds of millions of years, but, unfortunately, surviving human encroachment may be their biggest challenge ever. Through habitat enhancement and environmental education, humans may be able to ensure that these once endangered prehistoric reptiles practice their sophisticated survival skills for years to come.

Snowy owl with chicks during the summer. In wintertime, survival on Ellesmere becomes even more difficult.

Winter on Ellesmere Island is a far cry from the tranquil summer seen in White Falcon, White Wolf. As the most Northern part of Canada and extending into the Arctic Circle, Ellesmere Island experiences extreme winters. Shrouded in continual darkness, temperatures reach beyond “cold” to a bitter -20 or -30 degrees Fahrenheit. To survive in these harsh conditions, animals must develop special adaptations to stay warm, conserve energy, and find food in a barren, frozen world.

To stay warm, most animals rely on their thick winter coats. Some of these coats can be quite “high tech.” Polar bears have a watertight layer of insulating hairs, protected by a layer of longer guard hairs on top.  Other Arctic animals rely on a similar layered coat where guard hairs act as a protective shield against the elements. Arctic foxes, for example, have furry feet. The hairs on the soles of their feet help them retain heat as they trot across the tundra.

The ultimate goal of all arctic animals is to lose as little body heat as possible. In comparison to their cousins, the red foxes, arctic foxes have several morphological differences. The first, of course, is their coat color. Their coats change to all white as the winter begins, then turn brown again the next summer to allow for seasonal camouflage. Arctic foxes also have a rounder body, shorter legs, shorter tails, shorter muzzles, and shorter ears. These are adaptations common to Arctic animals. The more compact the body, the less heat is lost.

Besides physical features like fur and body proportions, Arctic animals have highly specialized thermoregulatory systems. The metabolisms of Arctic animals can adjust seasonally so that animals conserve energy during the winter. Arctic animals have to be able to adjust their systems to cope with lower caloric intakes, or even to go without food for long periods of time. To do so, animals must make the most out of what they can find during the winter. The musk ox, like most Arctic animals, does what it can to fatten up during the summer when food is abundant. During the winter when food is less accessible and less nutritious, musk ox rely on these fat reserves to help them avoid starvation. It can be difficult to find food during the winter. Plants exist in a dormant state between the frozen ground and the blanket of snow. The air trapped between these two layers acts as insulation, and the plants and lichen living under the snow mostly avoid freezing temperatures. But any creature that eats this winter vegetation must first be able to get at it. Musk ox and caribou dig through the snow with their hooves and horns, or graze in windswept areas where food is exposed.

What it takes to survive on Ellesmere Island today may be vastly different in the years to come. Climate change and global warming are already altering the landscape. Massive ice shelves larger than the island of Manhattan, and thousands of years old, are breaking off from the northern edge of Arctic Canada. Glaciers are retreating, and the average winter temperature is increasing. Most animals on Ellesmere Island are so well adapted to life in the Arctic that any change in climate could be catastrophic. Only time can tell what will happen to the handful of specialized animals that call Ellesmere home during winter.

For further information on climate change and the Arctic, visit our list of additional web and print resources.

Photo © Mark Smith 2007

GRADE LEVEL: 9-12

TIME ALLOTMENT: Two or three 45-minute class periods

OVERVIEW: Using segments from the PBS program NATURE: “Moment of Impact, Part 2: Jungle,” students will learn about skills and features that help species survive in the jungle. In the Introductory Activity, students will play a game where they are challenged to match species to adaptations which help them survive in the jungle. Students will create a definition for “adaptation” and revise the definition throughout the lesson, based on new information that they learn. In the Learning Activities, students will learn about the panther chameleon and the adaptations that help it survive. In an optional extension activity, students will examine the lyrics to “Karma Chameleon,” using their new knowledge of chameleons and will create a poem or song lyrics about chameleons. Students will also learn about the different layers of the jungle and the species that inhabit them, as well as how species get their prey and defend themselves from predators. In the Culminating Activity, students will create models illustrating the adaptations/skills different species use to survive.

SUBJECT MATTER: Science

Learning Objectives:
Students will be able to:
o Provide a definition for an “adaptation” and describe different adaptations that help species capture prey and protect themselves from predators.
o Describe a panther chameleon and list at least 3 adaptations that help it survive in the jungle.
o Discuss the different layers of the jungle, species that reside in each and adaptations that help them survive.
o Create a diagram and/or 3D model to explain an adaptation that helps a species survive.
o Describe one jungle species in detail and explain the features/ skills that help it survive.

STANDARDS
National Science Education Standards

Grades 9-12:
Content Standard C: Life Science
Fundamental concepts and principles that underlie this standard include:
• The Interdependence of Organisms
o Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years.
• The Behavior Of Organisms
o Multicellular animals have nervous systems that generate behavior. Nervous systems are formed from specialized cells that conduct signals rapidly through the long cell extensions that make up nerves. The nerve cells communicate with each other by secreting specific excitatory and inhibitory molecules. In sense organs, specialized cells detect light, sound, and specific chemicals and enable animals to monitor what is going on in the world around them.
o Organisms have behavioral responses to internal changes and to external stimuli. Responses to external stimuli can result from interactions with the organism’s own species and others, as well as environmental changes; these responses either can be innate or learned. The broad patterns of behavior exhibited by animals have evolved to ensure reproductive success. Animals often live in unpredictable environments, and so their behavior must be flexible enough to deal with uncertainty and change. Plants also respond to stimuli.
o Like other aspects of an organism’s biology, behaviors have evolved through natural selection. Behaviors often have an adaptive logic when viewed in terms of evolutionary principles.
o Behavioral biology has implications for humans, as it provides links to psychology, sociology, and anthropology.

MEDIA COMPONENTS
NATURE: “Moment of Impact, Part 2: Jungle,” selected segments
Note: Clip 1 is used in Learning Activity 1. The other clips can be used by students, as they create their culminating projects.

Clip 1: “Panther Chameleon”
An overview of what skills/features help the colorful panther chameleon survive in the jungle.

Clip 2: “Amazonian Boa”
An overview of the features that help the Amazonian boa capture prey and survive the jungle.

Clip 3: “Antsy on the Forest Floor”
A close look at the leafcutter and carnivorous trap-jaw ants.

Clip 4: “Bats”
A close look at bats and how they use sound to locate prey.

Clip 5: “Cuban Crocodile”
A look at the bioengineering of the Cuban crocodile and how it navigates in water and on land.

Clip 6: “The Lizard and the Butterfly”
A close look at a basilisk lizard’s surprise attack on an unsuspecting blue morpho butterfly.

Clip 7: “Monkey Business”
An overview of the spider monkey and how it moves through the jungle.

Clip 8: “Osprey”
A brief look at the osprey and how its body design is well-suited for spotting and capturing fish.

Clip 9: “Paradise Tree Snake”
A look at how the paradise tree snake escapes danger by “snaking” through the air.

Clip 10: “Red Eyed Tree Frog”
A look at how the paradise tree snake escapes danger by “snaking” through the air.

Clip 11: “Tiger”
A look at what makes the tiger a successful hunter.

Access the streaming and downloadable video segments for this lesson at the Video Segments Page.

Websites:
o Supporting Resources for the Lesson
The following sites are resources which can be helpful for students to use when conducting research during the following portions of the lesson:
Introductory Activity
• The BBC Virtual Jungle website
This website features a variety of information about the structure of the jungle and the plants and animals living there.
• Rainforest Alliance
This website contains a variety of information about rainforests, including a section about rainforest species (http://www.rainforest-alliance.org/resources.cfm?id=species_profiles) which could be helpful to students in this lesson.
Note: Both of these websites can also be used by students as resources throughout the lesson.

Learning Activity 2:
• Jungle Journey
In this section of the Nature website, students can explore the different layers of the jungle and the wildlife that inhabits each.

• The Layers of the Rainforest

This page contains info about the 4 rainforest layers, which can be used in Learning Activity #2. (This page is within the rainforest section of the California Institute of Technology’s Space Radiation Lab website)

• Mongabay.com
This website features a variety of information about wild lands and wildlife, including information about rainforests: http://rainforests.mongabay.com.

The following sections can be used to help students explore the layers of the rainforest in Learning Activity 2:
o The Canopy
o The Forest Floor

Optional Extension Activity:
• Karma Chameleon Lyrics
These lyrics to Boy George’s “Karma Chameleon” can be used in the optional activity.

Culminating Activity:
• Additional Resources Page
This page on the Nature website includes links to resources about blue morpho butterflies, tigers, trap-jaw ants, spider monkeys, snakes, Cuban crocodiles, tigers and other species, which could be used by students in the culminating activity.
• Animals of the Rainforest
This page provides details about different rainforest species including the blue morpho butterfly and spider monkey. (This page is within the rainforest section of the California Institue of Technology’s Space Radiation Lab website: http://www.srl.caltech.edu/personnel/krubal/rainforest/serve_home.html)
• Rainforest Connection
This Montclair State University website includes information about various species of mammals that live in the rainforest, including bats and spider monkeys, which students can use in the culminating activity. To directly access this information, students can go to the mammal index.

o Optional related website:
• Jungle Survival Game
This Discovery Channel Game challenges visitors to make decisions to help them survive in the jungle.

MATERIALS
For the class:
o Computers with internet access.
o Computer, projection screen and speakers (for class viewing of online/downloaded “Panther Chameleon” video segment).
o 1 copy of the “Adaptations Game” answer key.” (download here)

For each group of 5-10 students:
o 1 copy of the “Adaptations Game” (download here).

PREP FOR TEACHERS
Prior to teaching this lesson, you will need to:

Preview all of the video segments and websites used in the lesson.

Download the video clips used in the lesson to your classroom computer(s) or prepare to watch them using your classroom’s Internet connection.
Bookmark any websites that you plan to use in the lesson on each computer in your classroom. Using a social bookmarking tool such as del.icio.us or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.
Print out one copy of the “Adaptations Game” for each group of 5-10 students.

Print out one copy of the “Adaptations Game Answer Key.”

In the “Adaptations Game,” cut out each species card along the dotted lines and paper clip each set of 10 species cards to the corresponding box in the adaptations sheet.

Next: Proceed to Lesson Activities

Excerpts from the NATURE episode, “Moment of Impact: Part 2, Jungle”
Panther Chameleon
An overview of what skills/features help the colorful panther chameleon survive in the jungle.
(View full post to see video)
Amazonian Boa
An overview of the features that help the Amazonian boa capture prey and survive in the jungle.
(View full post to see video)
Antsy on the Forest Floor
A close look at the leafcutter and carnivorous trap-jaw ants.
(View full post to see video)
Bats
A close look at bats and how they use sound to locate prey.
(View full post to see video)
Cuban Crocodile
A look at the bioengineering of the Cuban crocodile and how it navigates in water and on land.
(View full post to see video)
The Lizard and the Butterfly
A close look at a basilisk lizard’s surprise attack on an unsuspecting blue morpho butterfly.
(View full post to see video)
Monkey Business
An overview of the spider monkey and how it moves through the jungle.
(View full post to see video)
Osprey
A brief look at the osprey and how its body design is well-suited for spotting and capturing fish.
(View full post to see video)
Paradise Tree Snake
A look at how the paradise tree snake escapes danger by “snaking” through the air.
(View full post to see video)
Red-eyed Tree Frog
A look at how the red-eyed tree frog changes its appearance to avoid danger.
(View full post to see video)
Tiger
A look at what makes the tiger a successful hunter.
(View full post to see video)

Downloadable QuickTime versions of the video segments:
(Note: To download a video, right click on the video title and click “Save Link As…’ or “Save Target As…”. On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)

Video Clips
1. Panther Chameleon
An overview of what skills/features help the colorful panther chameleon survive in the jungle.

2. Amazonian Boa
An overview of the features that help the Amazonian boa capture prey and survive in the jungle.

3. Antsy on the Forest Floor
A close look at the leafcutter and carnivorous trap-jaw ants.

4. Bats
A close look at bats and how they use sound to locate prey.

5. Cuban Crocodile
A look at the bioengineering of the Cuban crocodile and how it navigates in water and on land.

6. The Lizard and the Butterfly
A close look at a basilisk lizard’s surprise attack on an unsuspecting blue morpho butterfly.

7. Monkey Business
An overview of the spider monkey and how it moves through the jungle.

8. Osprey
A brief look at the osprey and how its body design is well-suited for spotting and capturing fish.

9. Paradise Tree Snake
A look at how the paradise tree snake escapes danger by “snaking” through the air.

10. Red-eyed Tree Frog
A look at how the red-eyed tree frog changes its appearance to avoid danger.

11. Tiger
A look at what makes the tiger a successful hunter.

2. Explain that today you are going to explore species living in the jungle and the adaptations and skills that help them survive. Ask students to brainstorm what they think an “adaptation” is. Write down all answers. (Possible points to raise during the discussion: An adaptation is a physical feature, behavior or skill, developed over the course of many generations, which helps a species survive. Adaptation also refers to the evolutionary process by which a species becomes better suited to its habitat.)

3. Ask students to list some animal adaptations. Write down their responses. (Answers might include camouflage, long necks to grab food in high places, etc.)

4. Let students know they will be playing a game where they will learn about various adaptations that help species survive in the jungle. Divide the class into groups of 5-10 students each. Give each group an “Adaptations Game.” (download here)

5. Challenge each group to match each species to an adaptation that helps it survive. Encourage students to use print and/or online resources to help them complete this task.
Note: Some of the featured adaptations are used by more than one of the species listed on the “Species Cards” and some of the species have more than one of the adaptations listed on the “Adaptations Sheet.” For this activity, challenge students to place only one species on each adaptation.

6. Once each group has successfully matched a species to an adaptation, encourage students to work alone or in pairs to gather information about each adaptation and how it helps the species survive. Each student or pair of students should select one adaptation to research. Encourage students to use a variety of print and/or online sources, including the BBC’s Virtual Jungle website . Give students about 15 minutes to conduct their research.

7. After the groups have collected their information, ask them to share their findings with the rest of the class. Lead a discussion about the adaptations featured in the game. Refer to the “Adaptations Game Answer Key,” as needed. During the discussion, talk about how each adaptation helps the species survive in the jungle. Refer to the table below for possible items to include in the discussion.

8. Review your description and examples of an “adaptation” that the class brainstormed earlier. Work with the class to revise the description. Encourage students to add more details to the definition of the adaptation. (For example: An adaptation is a physical feature or a skill, developed over the course of many generations which helps a species to find, capture and kill prey and to defend itself.)

9. Add additional examples of adaptations to the list, based on information gathered in the first activity. Create a three-column list, like the one shown below, to record student responses. (Leave room in the chart for students to add more information later in the lesson.

LEARNING ACTIVITY 1
1. Summarize that there are a variety of adaptations that help species defend themselves and find food in the jungle. FRAME clip #1, “Panther Chameleon,” by explaining that students will now learn more about a species called the panther chameleon and the adaptations that help it survive in the jungle.

2. Ask students to share information they know about chameleons. Write down the students’ responses. (Possible answers might include that they change color.) If students mention chameleons change color, ask them to brainstorm why they think this happens.

3. Explain that you are now going to show a video segment from the PBS program NATURE: “Moment of Impact, Part 2: Jungle.” Provide a FOCUS for the clip, asking students to list 3 different skills that help the panther chameleon survive and describe how each skill helps them in the jungle.

4. PLAY Video Segment #1, “Panther Chameleon.” After playing the clip, FOLLOW UP by asking students to list some adaptations (including special skills and physical features) the panther chameleon uses to survive and describe how each of those adaptations helps it. Access the video segments for this lesson at the Video Segments Page.
The discussion can include the following:
o How and why its color changes.
• How its color changes: The color change takes place below transparent outer skin. Chromatophores (stretchable pigment cells) are ringed with muscle fibers. When the fibers contract, they pull on the chromatophores, quickly spreading their color. The upper layer handles red and yellow tints. Another layer of cells below reflects blue light.
• Why its color changes: Panther chameleons don’t change color to camouflage their presence from surroundings. They change color to communicate. Coloring reflects their mood when sparring with other males or when attracting attention of females.

o Special skills/ features:
• Tongue: When extended, the panther chameleon’s tongue is longer than its body. The tongue enables the chameleon to quickly catch a prey. The sticky tip grabs the prey and its skin flaps keep it in place.
• Eyes: Each eye can rotate and focus separately. With a pinhole in the center, each eye has a full 360 degree view.
• Hunting Strategy: The chameleon edges toward the prey, but doesn’t chase it.

Optional Extension Activity
1. Share “Karma Chameleon” lyrics with students and play the song for the class to hear.

2. Ask students to reflect upon and discuss the lyrics in relation to what they know about chameleons. Ask students to look at the bolded words and phrases below. Ask students to conduct additional research about chameleons to see how accurately the bolded words and phrases (such as “cling” or “come and go”) describe chameleons:

When we cling our love is strong
When you go you’re gone forever
You string along, you string along

Karma karma karma karma, karma chameleon
You come and go, you come and go
Loving would be easy if your colors were like my dream
Red gold and green, red gold and green
Every day is like survival
You’re my lover, not my rival
Every day is like survival
You’re my lover, not my rival

3. Challenge students to write their own poem or song lyrics to the tune of “Karma Chameleon,” another existing song or an original composition, with words that accurately describe the panther chameleon’s adaptations. Here are two sample verses (to the tune of the last two “Karma Chameleon” verses listed above):
Panther, panther, panther, panther, panther chameleon
You move so slow, you move so slow
Your eyes keep movin’ & turnin’ around and around
You’re on the hunt, but don’t make a sound

Your hue is ever changing
Where you are we do not know
Your hue is ever changing
Where you are we do not know

4. After students have written their poems/verses, ask them to present and discuss them with the group.

LEARNING ACTIVITY 2
1. Divide students into four groups. Assign each group to one of the four layers of the jungle:
1) forest floor, 2) understory, 3) canopy and 4) emergent layer.

2. Give each group 15-20 minutes to research their assigned section of the jungle. Specifically, ask students to find out the following:
o Names of species living in the layer.
o Adaptations that help the species protect themselves and find food.
Encourage students to use online and print resources to gather the information. Here are some websites that could be helpful:
• The PBS Jungle Journey website
• The BBC Virtual Jungle website
• Mongabay.com’s rainforest information: http://rainforests.mongabay.com/:
•The Canopy
•The Forest Floor
• Layers of a Rainforest

3. Ask each group to present information about the layer it studied, the species that inhabit it and the adaptations that help them survive.

4. Lead a discussion with the group about the challenges of living in each of the layers of the jungle. Here are some possible items to include in the discussion:

5. Review the class’ 3-column chart of adaptations and add additional adaptations to the list.

CULMINATING ACTIVITY
1. Explain to students that, working in pairs or small groups, they will select a species that lives in the jungle, find out information about that species and create a 3-dimensional model or computer-animated model to illustrate how it seeks prey and/or defends itself in the jungle.

2. Ask students to review a few of the “Moment of Impact, Part 2: Jungle” video segments listed for this lesson in order to select the species they would like to research. (Access the video segments for this lesson at the Video Segments Page.) Ask each group to select one of the following species:
o Amazonian boa
o basilisk lizard
o bat
o Cuban crocodile
o leafcutter ant
o blue morpho butterfly
o osprey
o panther chameleon
o paradise tree snake
o red-eyed tree frog
o spider monkey
o tiger
o trap-jaw ant

3. Once students have selected their species, ask them to watch the corresponding segment again and record information about the highlighted adaptations. Encourage students to conduct additional research to find out more about their species.

4. Ask students to pick one or more adaptations to highlight in their project and to brainstorm the best ways to illustrate how that adaptation works. For example, if they have selected the panther chameleon, they could create a 3-d model of a panther chameleon that includes a “tongue” that extends to a length larger than the chameleon’s body, a body that changes color and/or eyes that each rotate 360 degrees.

5. The completed project could include a diagram, 3-d model and/or computer-generated animation and must include the following:
o Information about adaptations/features that help the species get food and/or defend itself against predators.
o A diagram, 3-d model or computer-generated video, created by the students, which demonstrates one or more skills/adaptations that help the species to survive. Here are some examples of adaptations that can be highlighted for each species:

6. Ask each group to present its work to the class and to lead a discussion about what it discovered about the species and its adaptations during the process.

7. Lead a discussion with the class, encouraging students to share facts they learned about the jungle, its species and their adaptations. Review the class’ definition of an “adaptation” and revise, as needed. Ask students to look at the class’ 3-column chart of adaptations and add new information learned during the lesson.

GRADE LEVEL: 5-8

TOPIC/SUBJECT MATTER: Life Science

TIME ALLOTMENT: One to two 45-minute class periods

OVERVIEW:

During this video-enhanced lesson, students will watch video segments from the NATURE film “The Secret World of Sharks and Rays” and learn about adaptations that have helped sharks and rays survive. Students will explore similarities and differences between sharks, rays and other fish. They will watch segments that provide information about physical features and behaviors that have helped sharks and rays survive, with specific attention paid to the angel, wobbegong and saw sharks and the electric, sting and manta rays. Students will work in small groups to research a specific type of shark or ray and share their findings with the class. Students will discover that different types of sharks and rays have different temperaments and diets and that some of the largest sharks and rays are the most gentle.

MEDIA RESOURCES

Video

Clip 1

Fish, Sharks and Rays: A comparison of fish, sharks and rays.

Clip 2

A Close Look at Sharks: A close look at angel, wobbegong and saw sharks and their survival techniques.

Clip 3

A Close Look at Rays: A close look at electric, sting and manta rays and their survival techniques.

Access the streaming and downloadable video segments for this lesson at the Video Segments Page.

Web sites

Ichthyology at the Florida Museum of Natural History

This site features a rich variety of information, games and photographs of a variety of fish, including sharks and rays. The following sections are recommended for this lesson:

• Sharks- This section features information, games and photographs of sharks.
• Biological Profiles- This section provides photographs and detailed information about specific sharks and rays, as well as other fish.

Kidzone Fun Facts for Kids: Sharks

This Web site features a variety of photographs, activities and facts about sharks.

National Geographic: Sharks
This Web site features many photos and facts about sharks, which can be used in this lesson.

Seaworld: Sharks and Rays

This site contains a variety of facts, photographs and diagrams of sharks and rays.

STANDARDS:

National Science Education Standards, Grades 5-8

LIFE SCIENCE: Content Standard C

As a result of their activities in grades 5-8, all students should develop understanding of

• Regulation and behavior
  • Behavior is one kind of response an organism can make to an internal or environmental stimulus. A behavioral response requires coordination and communication at many levels, including cells, organ systems, and whole organisms. Behavioral response is a set of actions determined in part by heredity and in part from experience.
  • An organism’s behavior evolves through adaptation to its environment. How a species moves, obtains food, reproduces, and responds to danger are based in the species’ evolutionary history.
• Populations and ecosystems

• Populations of organisms can be categorized by the function they serve in an ecosystem. Plants and some microorganisms are producers-they make their own food. All animals, including humans, are consumers, which obtain food by eating other organisms. Decomposers, primarily bacteria and fungi, are consumers that use waste materials and dead organisms for food. Food webs identify the relationships among producers, consumers, and decomposers in an ecosystem.

• Diversity and adaptations of organisms
  • Millions of species of animals, plants, and microorganisms are alive today. Although different species might look dissimilar, the unity among organisms becomes apparent from an analysis of internal structures, the similarity of their chemical processes, and the evidence of common ancestry.

• Biological evolution accounts for the diversity of species developed through gradual processes over many generations. Species acquire many of their unique characteristics through biological adaptation, which involves the selection of naturally occurring variations in populations. Biological adaptations include changes in structures, behaviors, or physiology that enhance survival and reproductive success in a particular environment.

MATERIALS

For each group of 2-3 students:

• Books, reference materials and/or computers to conduct research on sharks and rays.

For the class:

• A large sheet of paper or board and something with which to write.
• A photograph of a bull shark and a photograph of a whale shark. (See “Prep for Teachers” section for details.)
• One computer for the teacher with a digital projection system (to play video clips either downloaded or streaming from the Web).

OBJECTIVES

Students will be able to:

• Discuss similarities and differences between sharks, rays and other fish;
• Describe physical features and characteristics that have helped sharks survive, with specifics about angel, wobbegong and saw sharks;
• Provide details of physical features and characteristics that have helped rays survive, with specifics about electric, sting and manta rays;
• Explain that there are many different types of sharks and rays, with varied skills, physical features, temperaments and diets;
• Explain that some sharks and rays are harmful to humans, while others are not and provide specific examples of harmful and gentle species;
• Discuss that sometimes the largest species can be the most gentle;
• Provide detailed information about one species of shark or ray.

PREP FOR TEACHERS

Prior to teaching this lesson, you will need to:

Preview all of the video segments and Web sites used in the lesson.

Download the video clips used in the lesson to your classroom computer, or prepare to watch them using your classroom’s Internet connection.

Bookmark the Web sites used in the lesson on each computer in your classroom. Using a social bookmarking tool such as del.icio.us or diigo (or an online bookmarking utility such as portaportal) will allow you to organize all the links in a central location.

Print out one photo of a whale shark and one photo of a bull shark to show the class. Make sure that the image of the whale shark is about 3 times larger than the bull shark. See the “Web sites” section above for a list of sites with shark photos.

Proceed to ACTIVITIES

Downloadable QuickTime versions of the video segments:
(Note: To download a video, right click on the video title and click “Save Link As…’ or “Save Target As…”. On a Mac, press the CTRL key and simultaneously click the mouse, then save the link.)

Clip 1

Fish, Sharks and Rays

Clip 2

A Close Look at Sharks

Clip 3

A Close Look at Rays

Uncertain Future for the Alpine Red Deer

However inhospitable the weather may turn in the highest regions of the Austrian Alps, evolution has equipped the diverse species that claim these heights as their home with the ability to survive. The variations in weather are often sudden and intense, and the adaptations and perseverance required of these alpine creatures in order to ensure species survival are remarkable.

Throughout the year, Austria’s red deer roam the alpine environment in search of food. In summer, the red deer migrate to the highest altitudes and can stay there all season long. But, over the course of the season, the force of the elements can vary widely. Frequent lightning strikes can decimate entire herds that frequent these regions. If the mountain grasslands go dry or are over-grazed by local herds, the red deer will move down the mountainside to lower pastures where there may be more vegetation.

Come autumn, the red deer descend to lower elevations in the forested river valleys and graze on vegetation there before the long, grueling winter. When winter arrives, the landscape is transformed. Snow accumulation can exceed a person’s height in just a few days. Red deer forage for the sparse remaining vegetation on the cliffs, where winds have cleared the snow and left patches of plant life. The strongest deer are able to adapt and reduce their need to eat in winter. As they take in fewer calories, their heart rate, body temperature and metabolism are drastically lowered, and they slow down to reduce their energy expenditure.

In winter, snow accumulation can exceed a person’s height in just a few days.

Humans are changing everything and disrupting the process of natural selection. Many deer in the Alps can no longer survive the seasons on their own because they have come to depend on handouts from local landowners, farmers and even hunters who put out food to attract the deer. Austria’s red deer management program, too, in an effort to keep deer populations large enough to guarantee hunting success, have set up feeding stations in fenced enclosures near roads, where many deer spend more than half the year.

Each year it gets more difficult for the red deer to fend for themselves as humans encroach on their terrain. Busy roads, hunting stations, eco-unfriendly ski resorts, and the effects of global warming are threatening the long-term stability of red deer populations.

Along with the fenced enclosures for feeding, roads and highways are disrupting the deer’s migration route. More than 10 million trucks and about 50 million cars cross the Alps each year. Seventy-seven million tons of cargo move through the mountains in an average year, including furniture, chemicals, livestock, mineral water and automobiles. By 2020, some predict, Trans-Alpine commercial transport will double. The mountains concentrate the fumes from all these vehicles, and the greenhouse gas emissions are trapped in narrow valleys. The rapid increase in these carbon-emitting fossil fuels is expected to have a profound effect on the climate of the Alps. For the red deer, the problem is that they have adapted to the cold, barren conditions of Austria’s Alpine region. Biologists fear that if the temperature keeps rising, many alpine animals will face quick declines or extinction. According to the Austrian Central Institute for Meteorology and Geodynamics, the Alps are warmer today than anytime in the past 1,300 years. Some creatures have adapted to the constantly changing and gradually more restrictive environment — shifting breeding and migration dates, according to Science Magazine. But the red deer have fewer places to migrate, since they are surrounded by roads and ski resorts.

In 2007, Austria held an international conference on how to cope with the warm winters and lack of snowfall caused by global warming. However, the focus of the conference was not the animals and their habitat, but rather the impact of climate change on tourism and ski resorts. Austria’s Federal Forest Administration is working with land owners, communities and traffic authorities to protect wildlife corridors by building green bridges. And, ski resorts in the Alps are answering the demand for sustainable tourism by offering incentives for visitors who use public transportation and hybrid cars. But even with these green initiatives, it’s uncertain what lies ahead for these mountain dwellers when human encroachment and global warming threaten their natural resources and habitat.

We — and every other organism on earth — are only young once. But childhood may be the most important part of our lives, the time when we learn the skills that will help us survive for the rest of our years.

A face that, perhaps, only a mother could love. NATURE’s Baby Tales takes a serious but playful look at childhood in the animal kingdom. There are plenty of cute baby pictures, from the heart-melting face of a trembling calf to the toothy grin of a newborn alligator — a face only a mother could love.

While some — such as chimpanzees and elephants — may spend years with mom or dad, others — such as sea turtles and many insects — never know their parents, and must fend for themselves from the moment of birth.

Exactly how these newborns learn to survive isn’t completely understood. Some important behaviors, such as knowing how to head for the sea and not to climb higher on the beach, are somehow encoded in the animal’s genes. But youngsters also learn how to hunt and defend themselves by watching their parents and siblings. And scientists believe that some animals — from cats to crows — learn important survival skills by just playing.

Yes, that lion cub swatting at its sister, that puppy chewing on a stick, and that group of kids playing tag may be gaining important life experience. The lion, for instance, may be learning how to hunt, while the puppy strengthens its teeth. And the kids are learning important lessons in rule-making and cooperation.

A face that, perhaps, only a mother could love.

But researchers have long differed on the role of play in a young animal’s life. Many biologists, for instance, once believed that play is not a distinct form of behavior, and dismissed it as a purposeless collection of activities that had no benefit to the animal. Increasingly, however, researchers believe that many animals not only engage in play to learn skills, but because it brings them pleasure and is key to social development

In studies of rats, for instance, Columbia University researcher Susan Brunelli discovered that playful infants made better parents than those that didn’t play. Other studies have shown that cats, rats, and mice that goof around as youngsters have better developed brains and muscles than those who lived more boring lives. Indeed, these animals tend to play the most when key organs and tissues are developing quickly. Other research suggests that play helps youngsters burn off excess energy and weight, and stay cozily warm.

Play helps cement animal relationships. Most animals that exhibit playful behavior are birds or mammals that live highly social lives. Play helps cement their relationships. But some observers believe insects and other invertebrates may play too. The great evolutionary biologist Charles Darwin, for instance, reported in the 1800s that naturalists observed what they believed to be playing ants — tiny crawlers that nipped and chased each other for no apparent reason.

Most modern scientists doubt that playing ants exist. But more recently, researchers have suggested that octopuses might amuse themselves with games. In an unusual experiment, biologists Jennifer Mather of the University of Lethbridge in Alberta, Canada, and Roland Anderson of the Seattle Aquarium gave eight octopuses empty plastic pill bottles. At first, each animal grabbed the bottle and “tasted” it, seeing if it was good to eat. Then, several of the animals began pushing the bottles around with jets of water, with two of them “playing” with the bottles for at least 10 minutes. “If a human were doing this, someone might say we were bouncing a ball,” Mather told reporters.

Of course, it’s hard to know if the animals were amused or just practicing some arcane prey-catching skill. Either way, researchers say its worth paying more attention to how animals — particularly babies — spend their free time. Play may provide “promising evidence of animal minds,” says Marc Bekoff, a leading play researcher at the University of Colorado. It would be unfortunate, he says, “if people decided that just because play was difficult to study, it was impossible to study.”