GRADE LEVEL: 9-12

SUBJECT MATTER: Science

TIME ALLOTMENT: Two or three 45-minute class periods

OVERVIEW

In this lesson, students will use segments from Nature: Wild Balkans to explore the roles and interrelationships of organisms in the varied environments of the Balkan Peninsula. In the Introductory Activity, students will identify the Balkan Peninsula on a map and hypothesize what natural environments and wildlife might be present there. Students will use an interactive map to identify different regions of the Balkan Peninsula and the wildlife that resides in each region. In the Learning Activity, students will explore the regions of the Balkan Peninsula in more depth by viewing and discussing segments from the episode. Students will explore the habitats and wildlife of each region and the ways in which species collaborate and compete, as well as the role of humans in these environments. In the Culminating Activity, students will explore one species in depth and create a 3-D diorama or computer-generated simulation of the species in its environment. Students will discuss their projects with the class.

LEARNING OBJECTIVES

Students will be able to:

• Describe at least three different habitats in the Balkan Peninsula and the species that reside in each.
• Explain how species cooperate and compete within an ecosystem.
• Describe the roles that humans play in the Balkan Peninsula.
• Discuss one species in depth, including its preferred habitat and how it cooperates and/or competes with other species.

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
  • 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.
  • Living organisms have the capacity to produce populations of infinite size, but environments and resources are finite. This fundamental tension has profound effects on the interactions between organisms.
  • Human beings live within the world’s ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology, and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes, and other factors is threatening current global stability, and if not addressed, ecosystems will be irreversibly affected.
• The Behavior Of Organisms
  • 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.
  • 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.

MEDIA COMPONENTS

Nature: Wild Balkans, selected segments

• Danube Delta (Delta Dunarii)

A close look at the Danube Delta (Delta Dunarii), Europe’s most extensive wetland.

• Dobrudza

A look at the dry and stony region of Dobrudza.

• Durmitor

A look at the wildlife and terrain of Durmitor region of the Balkans.

• Kopacki Rit

A look at Kopacki Rit, one of Europe’s most extensive and important wetlands.

• Skadar Lake

A look at Skadar Lake, the largest lake in the Balkans.

• Tikves

A look at the terrain and the vultures & other inhabitants of the desolate, mountainous region of Tikves.

Access the streaming and downloadable video clips at the Video Segments Page.

Websites:

• Interactive Map: Wilderness of the Balkan Peninsula

This map on the Nature: Wild Balkans website highlights the different regions highlighted in the episode. This map is used in the Introductory Activity to provide an overview of the different regions of the Balkan Peninsula.

• Balkan Peninsula Map

This map features the countries of the Balkan Peninsula.

• Photo Gallery: Rare Animals of the Balkans

This page on the Nature: Wild Balkans website features images and descriptions of some of the Balkans’ rarest species. Students could use this as a resource in the Culminating Activity.

MATERIALS

For the class:

• Computers with internet access.
• Computer, projection screen and speakers (for class viewing of online/downloaded video segments).
• 1 copy of the “Regions of the Balkan Peninsula” answer key.

For each student:

• 1 copy of the “Regions of the Balkan Peninsula” student organizer.

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 “Regions of the Balkan Peninsula” student organizer for each student.

Print out one copy of the “Regions of the Balkan Peninsula” answer key.

Proceed to ACTIVITIES

Excerpts from the NATURE episode, Wild Balkans.

Danube Delta (Delta Dunarii)
(View full post to see video)
Dobrudza
(View full post to see video)
Durmitor
(View full post to see video)
Kopacki Rit
(View full post to see video)
Skadar Lake
(View full post to see video)
Tikves
(View full post to see video)

1. Danube Delta (Delta Dunarii)
A close look at the Danube Delta (Delta Dunarii), Europe’s most extensive wetland.

2. Dobrudza
A look at the dry and stony region of Dobrudza.

3. Durmitor
A look at the wildlife and terrain of Durmitor region of the Balkans.

4. Kopacki Rit
A look at Kopacki Rit, one of Europe’s most extensive and important wetlands.

5. Skadar Lake
A look at Skadar Lake, the largest lake in the Balkans.

6. Tikves
A look at the terrain and the vultures & other inhabitants of the desolate, mountainous region of Tikves.

It may be one of nature’s oddest couples: a tiny wasp that can barely be seen, and a giant fig tree, the sycomore, which shelters a remarkable menagerie of wildlife among its limbs. The wasp and the fig depend on each other for survival. Without the wasp, the tree could not pollinate its flowers and produce seeds. Without the fig, the wasp would have nowhere to lay its eggs.

The Queen of Trees shows this delicate dance of survival in exquisite detail, including spectacular close-ups of the wasp’s remarkable life inside a ripening fig. To capture such incredible images, filmmakers Victoria Stone and Mark Deeble spent two years camped out near a giant sycomore fig in Kenya’s outback, documenting the tree’s pivotal role as a source of food and shelter for everything from gray hornbills, Africa’s largest bird, to swarms of invading insects searching for food. In a surprising turn, some insects come to the tree’s aid — sparking a battle you won’t want to miss.

Online content for The Queen of Trees was originally posted April 2006.

To order a copy of The Queen of Trees, please visit the NATURE Shop.

Apple Varieties
http://www.bestapples.com/varieties/index.shtml
Pictures and information from the Washington apple industry on the different varieties of that favored fruit, from Granny Smiths to Pink Ladies.

How the Terminator Terminates
http://www.biotech-info.net/howto.html
Just how scientists can engineer some plants to produce sterile seeds.

Seasonal Burning
http://www.tallgrass.org/fire.html
Some great pictures of prairie plants that require fire to survive, from the Friends of the Prairie Learning Center in Iowa.

Carnivorous Plants
http://www.rdrop.com/users/mvz/plants.htm
Some plants eat insects! Here’s information on these bloodthirsty specimens.

Books

Briston, Alec. THE SEX LIFE OF PLANTS. New York: Holt, 1978.

Kuchalla, Susan. ALL ABOUT SEEDS. San Francisco: Troll Communications, 1988.

Morgan, Joan. THE BOOK OF APPLES. London: Ebury House, 1993.

Murray, David. SEED DISPERSAL. New York: Academic Press, 1987.

Overbeck, Cynthia. HOW SEEDS TRAVEL. New York: Lerner Publications Company, 1982.

Rodgers, Marc. SAVING SEEDS: THE GARDENER’S GUIDE TO GROWING AND STORING VEGETABLE AND FLOWER SEEDS. New York: Storey Books, 1991.

They fly, float, hitchhike — and even explode. But the many clever ways seeds get around make sense: after all, a plant’s life depends on finding fertile ground in which to grow. The quest for survival has even led plants to develop delightful and devious ways of fooling us into working for them as they send their seeds out to conquer new lands.

But the plants’ master plan for world conquest is no longer a secret. NATURE’s The Seedy Side of Plants rips the husk off the many remarkable ways plants make sure their offspring are spread far and wide. Apples make themselves as red and tempting as possible to encourage us to pluck them and take a bite so the seeds inside can escape to new ground. An African melon has a mouth-watering method of convincing aardvarks to go to the trouble of tunneling deep into the earth to liberate a few tough pits.

There is no doubt that plants are one of the world’s most successful life forms. Indeed, Earth is a planet of plants, with millions of kinds growing in virtually every environment imaginable, from the driest deserts to the wettest jungles. Even paved parking lots often display a few tufts of tough grass poking up through the cracks. But it didn’t take a gardener’s green thumb to design this global garden. Plants did it themselves, millions of years before humans ever appeared, by evolving countless methods of producing and spreading seeds. These tiny packages of genetic material have proven an almost unstoppable means of ensuring a species’ survival.

At first glance, some seeds’ designs make plants seem downright intelligent. Take apples, for instance. As The Seedy Side of Plants shows, these sweet fruits have evolved to be bright and shiny for good reason: they attract people and other animals. Drawn in by their effective advertising, we do the work of carrying apple seeds to new territory where the species can gain a toehold and expand. Indeed, we like apples so much that we’ve planted orchards especially for our favorite fruit. The practice has prompted some biologists to ask who really is the boss in this relationship: do the apple trees work for us — or do we work for them?

Similar examples can be found throughout nature, from fig-eating bats that become unwitting cargo planes for fig seeds, to squirrels and woodpeckers that unknowingly help oak trees spread their acorns. The Seedy Side of Plants even includes the remarkable tale of an African melon that grows a gourd-shaped bladder of water deep underground. In the dry season, aardvarks sniff out the watery melons, digging deep to quench their thirst. In the process, however, the thirsty aardvarks also sip up a few pit-like seeds, which they later deposit inside fertilizing manure. It’s hard to say who gets the better end of the deal: the melon or the mammal.

Both plant and animal, of course, get something out of these mutually beneficial relationships. Apple trees, for instance, didn’t set out to fool people into picking their fruit. But somewhere along the line, certain apple trees ended up with a combination of genes that made their fruit a bit brighter or sweeter than all the other apples. Since we liked these apples so much, we began selectively planting the trees, and learned how to breed even sweeter varieties. In exchange for the tender, nutritious fruit, the trees get steady care and even protection from potential enemies, such as insects and browsing deer.

Evolutionary accidents may explain how other types of seeds developed, too. On the island of Mauritius, for instance, there once were trees that dropped their tasty fruits full of seeds to the ground. Then, a new bird arrived on the island. It loved the fruits, but the tree’s seeds couldn’t survive the trip through the bird’s stomach. As a result, the tree was in trouble, since fewer of its seeds were surviving. Then, perhaps through a random genetic mutation, one tree, the calvaria, produced fruit with tougher seeds that could survive being eaten by the birds. Given this significant advantage, the tougher calvaria soon began to thrive. Eventually, they crowded out their ancestors completely.

As The Seedy Side of Plants shows, however, evolution can sometimes produce a plant that is too reliant on a particular animal for survival. That’s exactly what happened on Mauritius. There, some biologists believe that lonely 300-year-old calvaria trees await a bird that will never return: the dodo. In 1598, Dutch explorers established a colony on Mauritius. In the search for food to eat and sell, the settlers plundered the island’s natural resources, killing giant turtles, lizards, and the huge, flightless dodo birds with abandon. When the settlers did in the dodo, however, they may have also put the death of the calvaria in motion. Some biologists believe the dodos ate the tree’s fruit, and that the trip through the bird’s stomach helped prepare the seeds for germination. But now that their partner in life is gone, only a few calvaria survive. They are silent reminders of a lost past, with their seed-bearing fruit littering the ground and inviting a feast that will never come.

Plants have spent millions of years learning how to produce seeds that can ensure the birth of a new generation of plants. And people have spent thousands of years struggling to control that powerful force, breeding plants that produce more and better seeds than ever before. Indeed, modern agriculture depends in large part on our ability to control seed production: not only are seeds, from rice to wheat, a major source of our food, but we also depend on being able to store and plant them for the next year’s crop.

Now, however, scientists armed with the tools of modern genetic engineering are engaged in a controversial attempt to turn back the evolutionary clock by creating plants whose seeds do not work. Why would researchers want to prevent a plant from reproducing?

The answer lies in the economics of modern farming, where farmers in industrialized nations are willing to pay a fortune for seeds that can guarantee a bountiful harvest. But such revolutionary seeds are also expensive to develop, and seed companies are spending billions to engineer new varieties of many modern crops — from corn to cotton — that grow or taste better. In the past, a farmer may have been able to buy these relatively expensive seeds, harvest a crop, and then, by saving some of the seeds produced by the superplants, plant a new crop the next year without having to buy a new batch of seeds. Understandably, some companies were unhappy about spending so much to develop seeds that could be so easily “stolen.”

So now, these companies have figured out a way to turn off a plant’s ability to produce viable seed. By inserting a certain gene into the plant, the seed-growing process is short-circuited. While the plants produce lots of seeds, the packets are all sterile.

This “terminator technology,” as it is popularly called, isn’t yet out on the market. It is still being fine-tuned in the laboratory and in test plots. But it has already prompted protests around the world, particularly from poor farmers who depend on saved seeds for the next year’s crop. And some biologists worry the trait could somehow spread to related wild plants, endangering their ability to reproduce. The companies say such fears are unfounded and promise they won’t release the seeds until they’ve been shown to be safe.

The debate is unlikely to be settled soon, but it shows that even seeds no bigger than a speck of dust can spark huge debates.

In their quest to spread their seeds, plants have proved endlessly adaptable. Some, such as dandelions, produce spores that can fly miles on a puff of wind. Others, like coconuts, have engineered seeds that can survive thousand-mile voyages at sea. Some of the most remarkable seeds, however, are those adapted to survive fires so intense they kill virtually everything else in their path.

Many of the world’s pine forests, for instance, grow in arid climates, where a single flash of lightning can spark an inferno. Trees that couldn’t take the heat died out long ago. Those that remain generate seeds that are fire-hardened better than any high-security safe, able to protect their precious genetic cargo from the heat.

Some seeds, however, recall the mythical Phoenix, a bird that would rise from a fire’s ashes to begin life anew. To thrive, these seeds actually need to get burned: intense heat is required to explode their seed cones or crack their hard kernels, so that water can leak in and begin the growth process. Such “fire-germinated” species are common everywhere forest fires occur on a regular basis. In an ironic turn of events, the recent campaign to stamp out forest fires has put some of these species in jeopardy. Indeed, in some parks, rangers now intentionally set forest fires just to make sure certain plants grow.

Many prairie species, for instance, only sprout after fires clear the way. That has made the spring “prairie burn” an annual ritual throughout much of the Midwest, with teams of fire-wielding plant-lovers tromping into the fields in a quest to imitate the grass fires that once swept across the plains. In Michigan, biologists have also become fervent arsonists in an effort to make sure there are enough young jack pines, a kind of tree essential to the survival of an endangered songbird called the Kirtland’s warbler. For some reason, the bird will nest only in the young pines — and the trees will grow only in recently burned forests. That’s because fire is needed to get the pines’ tough cones to crack open and release their cargo of seeds.

Recently, however, biologists have learned that flames aren’t enough to unlock some fire-resistant seeds — they need the smoke as well. In the 1970s, researchers discovered that some seeds germinate when exposed to the merest whiff of wood smoke, even if the seed is buried in the soil. The response makes sense: the seeds can wait years underground until smoke reveals that a fire has taken place overhead, filling the soil with fertilizing ash and clearing away plants that might block the seedling’s light. Having gotten its smoke signal, the young plant can take advantage of the disaster.

But smoke is made of literally thousands of chemicals, and researchers have long puzzled over which ones might be triggering the seeds. Then, in 1997, researchers Jon Keeley and C. J. Fothereringham of Occidental College in California were able to pin down one of the responsible agents: a gas called nitrogen dioxide. They discovered that the seeds of a common wildflower called yellow whispering bells germinated when exposed to even tiny amounts of the gas. The discovery, however, had a troubling side. Nitrogen dioxide is produced by natural fires — but it is also one of the most common pollutants produced by cars and power plants. Tons of the compound fall to Earth every day, carried by rain and dust particles. Some botanists fear the pollution could be tricking sleeping whispering bells seeds into thinking a fire has occurred — causing them to sprout beneath the deadly shade of another plant. That would mean fewer seeds would be around when a fire really occurs.

Like other plants, however, even whispering bells show creative variation in getting their seeds to sprout. While those that live in fire-prone areas need smoke to germinate, whispering bells living in deserts, where fires are scarce, don’t respond to smoke at all. Instead, they have evolved a clever response to the desert’s scouring winds. For these seeds to germinate, they must be blown across rough sand, which scratches the seed’s outer coat. Moisture then leaks in through the scratches, signaling the seed that it is time to grow.

Such strategies don’t surprise botanists. Says one: “If you can think of a way to get a seed to sprout, you can be sure some plant is already doing it.”

They’re cunning and manipulative, and will do anything to get what they want. No, it’s not the cast of your favorite daytime soap. We’re speaking of the ubiquitous plant life that covers our planet, relentlessly evolving elaborate schemes to disperse its seeds and ensure the continuation of its almost limitless species.

How does such a seemingly passive life form accomplish the complex task of reproduction? Many plants take advantage of the primeval forces of Mother Nature herself to help their seeds germinate, sending them far and wide by means of wind, rain, and tides. Others have found ways to hitch rides for their seeds aboard other living things. For example, the burdock plant, which inspired inventor George de Mestral to create Velcro, has pesky burrs that sticks stubbornly to hair and fur.

Fruit, however, is perhaps the most commonly employed medium of seed mobility. Fruit-producing plants rely on the appeal of their fruits for dispersal of the seeds, and have evolved their own unique “marketing strategies” and their own select clientele — animals as well as humans — to help the process along. Even as scientists develop methods to control plant reproduction, each time we yield to the temptation to pluck a ripe juicy apple from its branch, we too become pawns in one of nature’s carefully devised game plans.

Online ontent for The Seedy Side of Plants was originally posted May 1999.

SUNDEW (Drosera roraimae)

Just call it the flypaper plant. The drosera, found throughout the world, features long leaves with tentacles sticky with nectar, digestive enzymes, and adhesive. Attracted by the nectar, visiting insects find themselves literally glued to the spot. Additional tentacles then move in to anchor the struggling insect. At times, the entire leaf will surround it. Once sure of its prey, the plant sends the digestive enzymes into action. Bug eaten, the leaves open again, releasing the insect’s shell to the wind. In the Lost World, the sundew lives on the tepuis’ surface, where it can soak up the maximum sunlight its multiple flowers — sometimes up to 50 per plant stem — require.

SUN PITCHER (Heliamphora)

A tepuis native, sun pitchers live for bugs. As rain fills the pitcher, the plant’s sides begin to curve in towards its upper section. The section, known as a bell, features a slippery surface that forces unwitting insects attracted by the pitcher’s red nectar stem to fall into the water below. Those bugs that don’t manage to fly out before hitting the water are absorbed through plant bacteria. When temperatures are moderate (61 to 80° F) with damp, humid atmospheric conditions, the sun pitcher flourishes in five species: Heliamphora heterodoxa (olive green, with a red line on the rim and pink and white flowers); Heliamphora ionasi (features a large red nectar spoon and can stand up to 18 inches tall); Heliamphora minor (at three inches tall, the smallest species); Heliamphora nutans, and Heliamphora tatei.

BROMELIADS

Though a relative of the pineapple, the tepuis’ two bromeliad species are more pitcher plant knock-offs than tropical fruit. The bromeliads use the same techniques as the pitcher plant to attract their bugs, but also will take in decaying organic matter and dust. They can be found on rocks or tree limbs. The tepuis bromeliads’ talent for insect digestion is not shared by other bromeliads elsewhere — it’s an attribute essential for survival in terra tepui.

ORCHIDS

Tepuis country is an orchid lover’s paradise. As one orchid tourist to the Lost World recalls in his Web journal, “We were approaching nirvana.” An estimated 500 species grow throughout Canaima National Park. Here, orchids are almost a casual wildflower and grow effortlessly on leaves, rocks, trees, sand, and soil. Some clusters can be found growing up to 6.5 feet tall. One native favored by the Pemón for decoration is the Cattelaya jenmanii, found at altitudes between 1,312 and 3,280 feet in the Roraima area of Bolivar State and in Guyana. Horticulturalists temporarily lost track of this purple orchid for 63 years until it was reidentified in 1969. BLADDERWORT (Utricularia)

Another insectivorous plant, bladderworts like the Urticularia humboldtii (named after 19th century explorer Alexander Humboldt) favor the tepuis summit where they can get steady sun. Their roots prefer cool, boggy land. Their flowers are usually violet with a sunny orange center. Found on Mount Roraima, this bladderwort digests insects via the “bladders” on its aquatic roots. The Utricularia humboldtii is the largest of the bladderworts and is prized by horticulturalists for its beauty.

Hungry for greens? The Pemón say sucking on the leaves of this fan-shaped plant could keep you alive for weeks:

Stegolepis

Chimantaea cinerea

Heliamphora

Drosera roraimae

If you’re thinking of walking off with a pitcher plant or plucking a rosy orchid as a tropical keepsake, think again. Only the Pemón have an official right to gather vegetation grown on the Gran Sabana.