Backyard Borgia A child climbing up a a tree, a hunter, a lumberman, a woman burning autumn leaves, or another weeding her garden may all fall victim to the backyard Borgia: poison ivy. Dr. Charles Dawson wondered what made poison ivy “poisonous.” After 13 years of research, he extracted less than an ounce of oil from 80 pounds of poison ivy bark. From this he revealed the secret of poison-ivy: a variable blend of four chemicals. Allergic reactions to poison ivy vary. But no matter what your past history, beware! Sooner or later, repeated exposure usually results in poisoning. So watch out for the three leafed backyard Borgia. A number of vegetables come from plants once believed to be poisonous. Tomatoes and potatoes come from plants in the deadly nightshade family. What part of these plants most likely contains poison? Explain.
The Laid-Bare Plants of Scotland Psilophyton is the earliest known plant with conductive tissue. It was discovered by a doctor who enjoyed who enjoyed nature and strolling along the seashore. In the early 1800’s, Dr. Mackie found some unique fossils near the village of Thynie in Scotland. He sent them to Sir William Dawson, a famous botanist, who named them Psilophyton, “the laid-bare plants.” Dawson studied them and described their place in evolution. In the Ordovician Period, that part of Scotland was a muddy seashore. At that time, in that place, stems of Psilophyton flourished. The whisk fern of Florida and Bermuda are living examples of plants that have changed little since the shores of Thynie began to grow green. Why do you think some plants, or their relatives, have changed so little over millions of years?
Love Apples What “poisonous” plant is the main ingredient in America’s favorite condiment? In colonial New England, the love apple was an ornamental plant. The lovely red fruit graced many a garden, but no one’s table. The love apple was widely believed to be as deadly as it was beautiful. All this intrigue about a … tomato! Tomatoes belong to the “deadly” nightshade plant family. Based on this, why do you think the idea of poisonous love apples is not really outlandish? Explain.
DNA from Ancient Brains The girl was interred on a grass mat under durable, woven cloth. Her grave was filled with gifts, trinkets, and tools. Stakes held the body in place, in a Florida peat bog, for 8,000 years! Her skin, muscles, and internal organs had decayed, but the small skeleton endured. Her brain as shrunken and discolored, but so well preserved that tissue samples are intact. Scientists can even examine the girl’s DNA, her genetic code! Seamus Heaney, an Irish poet (not an archeologist or geneticist) had this to say: “The peat is the dark casket, where we have found many clues to our past and to our cultural identity.” What do you think we could learn from the DNA of our ancient ancestors?
Least, Most, Oldest, Newest These words describe bacteria. But how can bacteria be all of these things at once. At an average size of less than a micron, bacteria are the smallest – least in size- of all known life forms. Thirty trillion bacteria weigh only an ounce. Bacteria are the most numerous organisms on the planet. In a pail full of good humus, there are more bacteria than all the humans living on Earth. Fossil bacteria have been found in South African black chert (rock) well over 3.2 billion years old. So bacteria are the oldest. Scientists use recombinant DNA to make bacteria, the newest organisms we have. So bacteria are the least, most, oldest, and newest of living things. How are bacteria a study in contradictions? Go beyond the content of this warm-up to justify your answer.
Bring Out Your Dead! Several hundred years ago, in a dusty alley in a small North African seaport, a flea jumped onto the back of a dying rat, and bit it. On another continent, millions of people would die because of that flea bite. Disease bacteria from the rat grew inside the flea. The flea onto a passing sailor and bit him, injecting the man with dead If the sailor noticed the flea bite, he thought little of it. Vermin of his life. Yet only five days out to sea, after a bout of fever, chills, and with ugly discolored lumps under both arms, the sailor’s dead body was thrown into the sea. Sickness spread to the crew- and to the ship’s rats. The rats passed the disease to more fleas. On arrival in Italy, the s hip delivered a cargo of death. The ship delivered bubonic plaque to Europe. The plaque spread quickly and killed many. Medieval workers walked the streets chanting, “Bring out your dead!” in an attempt to keep up with all the burials. If you were a public health worker, what steps would you take to protect people from an epidemic? Be specific.
Mad Dog or Sad Dog? The boys saw their dog staggering up the path, his head lolling. He was stumbling, with frothy saliva covering his snout and drool dripping from his slack jaw. “Don’t touch Spotty!” What did the older boy think was wrong with the dog? What do you think? “Leave Spotty alone!” the boy warned. “He has rabies.” After examining the dog, the veterinarian confirmed a different diagnosis. “Your dog will be all right unless he tries to eat another toad. Chemicals from the toad’s skin glands, the ‘warts,’ caused the dog’s symptoms. Your dog isn’t rabid; he’s just a sad dog – sadder but wiser.” People do not get warts from toads. Those growths on toad skin are glands, not warts. What do you think toad “warts” contain that is harmful to other animals?
The Normandy Invasion Can starvation be a survival strategy? The answer lies on the beaches of Normandy, the scene of a great World War II battle. The soldiers fighting there most certainly didn’t notice the pale green worms invading the troubled shores with them. Convoluta worms hatch in early spring. They crawl about in the mud feeding algae, which find their way into the skin of the worms. There they prosper as the worms feed on the sun-warmed surface mud. The worms become greener and greener as they mature. Gradually their mouths seal shut, leaving only an internal garden of algae to provide them with food. As winter approaches, their food supply is exhausted, and the worms grow pale again. They lay their eggs in the mud just before they starve to death. Each spring the eggs hatch and little worms reinvade the famous beaches of Normandy. In this way, the species survives. How do you think both worms and algae profit from this relationship? Why?
Remarkable, Remarkable Worms Which invertebrate can have two heads, two tails – even two bodies? The answer is planaria, the remarkable, “remake-able” worm. Experiments show planaria are capable of growing new heads, tails, and bodies. Split heads or tails, held apart while they heal, produce worms with double heads, double tails, or both. One scientist trained planaria to go through a maze to get food. Planaria that learned the maze were ground up and fed to “untrained” planaria. The cannibals ran the maze with ease, apparently having learned at lunch. Other biologists disagree. They say planaria don’t “learn” anything. They just follow the slime trails left in the maze by the first set of worms. Design a simple experiment to settle the matter.
Where Does a Half-ton Bird Sleep? Where does a thousand-pound bird sleep? The punch line ought to be: “Anywhere it wants!” But this is no joke. The answer is in the prehistory of Madagascar. When the massive bones of Aepyornis maximus were unearthed by scientists almost 140 years ago, the discovery created a sensation. Aepyoornis would have stood nine of ten feet high and walked rather than run. Most certainly this half-ton bird never flew! The last of these fabulous birds died some 2,000 years ago. It was a relic of the burst of adaptive radiation that produced modern birds after the demise of the dinosaurs. Ostriches and emus are the largest living birds. How does Aepyornis compare with them?
The Adopt-a-Bird Racket Seven hundred years ago, cowbirds grew plump on the insects that skittered ahead of herds of grazing bison. Cowbirds traveled on the bisons’ humps when life was leisurely and paced the herd in stampedes. Bison calves trot alongside their mothers moments after birth, but not so baby cow birds. How do herd-following cowbirds deal with nesting and the care of baby birds? Cowbirds developed the habit of putting their eggs up for adoption. Female cowbirds lay eggs in the nests of other birds. Cowbird chicks, born sooner and larger than nest mates, often push their potential rivals out of the nest and hog all the food and care offered by their adoptive parents. What would you call the relationship between cowbirds and the other birds whose nests they use?
Sweet Firebird The jack-pine barrens in Michigan are home to a bird whose life depends on forest fires. Kirtland’s warblers mate only in jack-pine barrens. The pines produce seed cones so dense that only the heat of a forest fire can free the seeds. So forest fires help jack-pine trees reproduce and maintain the forest. Unless fires regularly sweep through the barrens, both the pines and the sweet-singing firebird would become extinct. Do you think protecting jack pines from forest fires is poor conservation? Explain.
Ten Months’ Vacation, Anyone? Scientists trace corn’s development to fertile lands along what is now the U.S. border with Mexico. To early American Indians, corn was a gift from the gods. About 50 days of work a year in the cornfields provided the Indians of Mexico and Central America with more corn than they needed. With the time and wealth that corn provided, they accomplished much in mathematics, astronomy, science, agriculture, art, and religion. How would a large, surplus crop of corn have given people the time to develop religion, mathematics, astronomy, and agriculture?
As American as Apple Pie? How “American” is apple pie? Stone Age people – the lake dwellers of Central Europe – collected apples to eat fresh or to dry for later use. Apples probably developed in the fertile land between the Black and Caspian seas and spread with civilization through Europe. Considering their popularity, food value, and ease of storage, it is not surprising that Dutch, French, and English settlers brought apples to the New World. Like carrots and a few other imported delicacies, apples were prized by the American Indians, who traded apple seeds across the continent. Explain the two methods of plant reproduction expressed in this statement: New varieties of apples grow from seeds; old varieties grow from trees.
Snakeroot In tall grass, without warning, the cobra struck. The boy screamed. Moments later, his parents, peasants in ancient India, sent his sister to the healer for a bit of dried, shriveled root to treat the bite. Thousands of years ago, merchants in dusty bazaars offered Rauwolfia roots as a cure for snakebite. It is sold there still. Snakeroot, Rauwolfia serpentina, first described in scientific literature by Leonhard Rauwolf in the late sixteenth century, is regarded as a medicinal plant today. Derivatives are used as sedatives and to combat high blood pressure. How do you think primitive people first discovered the uses for medicinal plants?
Tonic, Treat, or Fodder What vegetable native to Afghanistan became a favorite of American Indians? The lacy-leafed, tap-rooted plants grew first on the windswept highlands of Afghanistan. The Greeks used this plant as a digestive tonic when they had overeaten other foods. The Romans disdained this plant as food, but maintained that it improved the flavor of lambs fattened on the plant. The Jamestown colonists shared the roots with their Indian neighbors, who traded with other tribes. So widely traded were the seeds that Lewis and Clark concluded that carrots must have been indigenous to North America! How might knowing where a vegetable originated help agriculturalists improve a modern vegetable?
The Great Tilefish Mystery Never had Captain Kirby seen the like of it – bright blue fish decorated with yellow spots on their rosy white undersides. They were big fish, a yard long, firm and, it turned out, very tasty! It was 1879 and Kirby was just south of Nantucket shoals in well-fished waters. Only two years later, tilefish, as they came to be called, were the basis of a successful fishery. A greater mystery unfolded in March 1882, with the discovery of acres of dead tilefish floating on the sea’s surface. More than 1.5 billion had died from an unknown cause. At first, it was thought they’d become extinct. But by 1892, tilefish were being caught again, in ever larger numbers. It is now believed that tilefish were being caught again, in ever larger numbers. It is now believed that tilefish are highly susceptible to changes in ocean temperature. A minor drop in water temperature most likely caused the great tilefish kill of 1882
Caribbean Cannibals Could cannibalism work as a survival strategy for an entire species? The little sargassum fish, camouflaged in the canopy of gulfweed, were nearly invisible. But two green eyes, luminous in the dappled light, ominous and intense, followed. One little fish darted close. A gaping mouth opened. Caught in the inrushing water, the small sargassum fish became the meal of the larger sargassum fish. The Caribbean cannibal had struck again. Cannibalism is well-documented among pelagic fish. It appears to be a survival strategy. Speculate about how eating its own young could help a species survive.
Portable Pastures What makes a weed a weed? The ship’s captain believed that the plants that fouled his propeller would cost him the tide and a head start. To him, water hyacinth is a weed a harbor-clogging, equipment – fouling nuisance. This rootless plant grows in clusters, some as large as a suburban lawn. Almost without natural enemies, the water hyacinth spreads over navigational buoys, reefs, and channels. It fouls nets, propellers, pumps, and anchor cables. However, this “nuisance” could be towed where it would be a welcome producer of livestock fodder. Or it cold be used to clear polluted harbors. In your opinion, is water hyacinth a weed or a crop?
Asia’s Fruit of Gold Where did the orange in your lunchbox originally come from? The first oranges grew in the tropical forests of southern China, possibly in Vietnam or Cambodia. How they spread to Sprain and Portugal is unknown. We do know that orange seeds came to the New World with Christopher Columbus. Oranges grew in Central American, then in Mexico. Settlers in Saint Augustine, Florida, planted that state’s first oranges. Despite their long history of cultivation, oranges were a luxury item as recently as the turn of the last century. Grandparents may remember oranges as a special treat at Christmas. Think about your great grandparents or other senior citizens who might remember oranges as a childhood treat. What other changes in diet do you think they have seen in their lifetime?
The Bird Shooter’s Apprentice At 13, Joseph Mason was apprenticed to a master with questionable credentials, a man only recently released from jail for debt. The man had failed as a farmer, a merchant, and a miller. He was bankrupt. The lean woodsman had only two skills: shooting birds and painting them in startling, lifelike poses. Mason and his new master set out by flatboat from Cincinnati, Ohio, in the autumn of 1820. By the time they reached Natchez, Mississippi, they were penniless. In New Orleans, the two painted portraits for food money. In time, the master achieved great fame as a painter of birds. His name was John James Audubon. How might an artist – a painter of birds, for example – assist biologists in their studies?
Mornings Strangely Silent “Over increasingly large areas of the United States, spring now comes unheralded by the return of birds, and the early mornings and strangely silent, where once they were filled with the beauty of birdsong.” In her 1962 book Silent Spring, Rachel Carson, who wrote these words, believed that damage to the environment would bring greater trouble than springs without birdsong. How does damage to the environment harm birds and other wildlife?
Just the Facts A famous police detective in the 1950’s TV series Dragnet used to say, “ The facts. Just the facts, ma’am.” French scientist Jules Henri Poincare’ once said, “Science is built up with facts, as a house is with stones. But a collection of facts is no more a science than a heap of stones is a house.” Compose a statement about the importance of facts in biology – and what it takes to make those facts science.
The President Speaks In his inaugural address, President Harry S Truman had this to say about science: “We must embark on a bold new program for making the benefits of our scientific knowledge and industrial progress available for the improvement and growth of underdeveloped areas.” More than half the world’s people are living in misery. Food and freshwater are scarce. Disease is common. Economic life is primitive and stagnant. Poverty is a handicap and a threat. Assume the rold of speech writer and science consultant and write a brief paragraph outlining the next president’s ideas about how biology can help humanity.
Mussel Bomber The falling tide exposed more of the shore to the gulls foraging in the seaweed. One pecked at a mussel, twisting and tugging until the mollusk’s anchoring fibers broke. The gull took off with the mussel in its beak and dropped it on a ledge 50 feet below. The impact finished what the gull had started: the shell broke. Then the gull swooped down and gobbled up the rich mussel meat before another bird snatched it. Do you think this feeding behavior is a learned or an inherited trait? Defend your answer.
Mystery of Migration Why do birds migrate? It makes sense. They fly south in the winter to find ample food and a milder climate. They fly north in spring to breed when food is abundant there. But how can we be sure this explains migration? For more than 100 year, humans have used every tool, from simple observation to electronic satellite tracking, to study bird migration. Yet we cannot even state with certainty why birds migrate, how they navigate, or how such behavior developed. Some birds migrate by day, others by night. What do you think might e the advantages and disadvantages of each strategy?
Rotting Fish, Starving People Hunger is a problem in many parts of the world. In some places, if fish could be delivered fresh, people would have the protein they need to live. Bacteria are the primary cause of decay. Decay is delayed by refrigeration. But in some parts of the world, refrigeration is unknown, and sterile canning is too costly. Scientists are getting good results with a low-technology solution. They are blanching fresh-caught fish in 194* water (90* Celsius), then shipping them in salted ice. Explain how blanching fish and salting the ice keep the fish fresh.
Bring Out Your Dead! Several hundred years ago, in a dusty alley in a small North African seaport, a flea jumped onto the back of a dying rat, and bit it. On another continent, millions of people would die because of that flea bite. Disease bacteria from the rat grew inside the flea. The flea hopped onto a passing sailor and bit him, injecting the man with deadly germs. If the sailor noticed the flea bite, he thought little of it. Vermin were part of his life. Yet only five days out to sea, after a bout of fever, chills, and with ugly discolored lumps under both arms, the sailor’s dead body was thrown into the sea. Sickness spread to the crew – and to the ship’s rats. The rats passed the disease to more fleas. On arrival in Italy, the ship delivered a cargo of death. The ship delivered bubonic plaque to Europe. The plaque spread quickly and killed many. Medieval workers walked the streets chanting, “Bring out your dead!” in an attempt to keep up with all the burials. If you were a public health worker, what steps would you take to protect people from an epidemic? Be specific.
Drifters, Swimmers, Plowers, Burrowers They came in different shapes and sizes. They lived in all parts of the oceans. One was like a living bulldozer – the small animal plowed through the sea-floor sand, showing little more than it’s compound eyes. The top of its armored body was divided into three lobes. It moved on jointed legs. Other tiny, spiny bodies drifted through the ocean waters. Still other species burrowed deep into the seabed. For 500 million years, these little arthropods dominated the sea. When they died, their shells piled up. Some became fossils, which people study to learn about ancient life in the oceans. These drifters, swimmers, plowers, and burrowers are called trilobites. Why do you think such a large, diverse, and successful group as trilobites became extinct?
The Beautiful, the Mysterious “The most beautiful thing we can experience is the mysterious. It is the source of all true art and science.” Albert Einstein wrote these words in “What I Believe,” for the Forum in October 1930. Einstein was a mathematician and physicist. His scientific research contributed to the building of the first atomic bomb. He later wrote, “The unleashed power of the atom has changed everything save our modes of thinking, and we thus drift toward unparalleled catastrophes.” What do these words tell you about Einstein and his attitude toward science? What do you think should be the moral and social responsibilities of scientists?
Speaking Biologically A startled crayfish flips its tail and abdomen and scoots away from danger. From that easily observed behavior comes the slang expression crawfishing – backing away from a deal, a promise, or an obligation. Think of people described as wolves, loan sharks, rats, lambs, sheep, guinea pigs, goats, asses. We can be sheepish, chicken, mousy, and – well, you get the idea. In how many ways does biology creep into our daily speech? How man biological expressions can you think of?
Regenerating Lost Limbs Among vertebrates, only amphibians with tails can replace lost limbs or other major structures. Amphibians’ bones, muscles, nerves, and tissues are not so different from those of other vertebrates. Why then can tailed amphibians replace lost limbs and other vertebrates cannot? Medical researchers find this question intriguing. They have found some differences between amphibians and other vertebrates. One difference is electrical activity in amphibian skin. A sodium – transport mechanism generates electricity. Research indicates that’s a factor in their ability to replace amputated limbs. Do you know of any other animals that have the power to regenerate?
A Fable of Two Kingdoms Once upon a time, two great armored legions confronted each other on the seashore. Both sides sought dominion over Earth. Their leaders were determined to settle t heir differences by diplomacy, not war. It was decided that the rich and diverse land would go to one group. The other group would rule the vast sea. Which invertebrates are described in this fable? The opponents were insects and crustaceans. Insects got the land; crustaceans got the oceans. Only in freshwater would their descendants share territory. This has been the case ever since. Many biological truths might be explained by fables, folklore, or legend. Compose a short fable of your own about a biological truth.
Together We Stand All around the two wounded men, the battle for Gettysburg raged. A single shell burst blinded the soldier in blue, crippled the man in gray, and ended their war. They lay sprawled, talking to each other to ease the pain and fear of dying. It occurred to them that thirst and gunfire were the real enemy. If they could get to Spangler’s Spring at the base of Culp’s Hill, they would have water and shelter. The blind man supported the cripple. The cripple directed the blind man. Together they had what it would take to survive in a hostile world where neither could survive independently. Their partnership seems very human. But biology is filled with unions of organisms even more different than the soldiers in this story. What other mutually beneficial relationships occur in nature?
How’s That Again? The boy attacked the alligator! Believe it or not, an 11 year old boy attacked an alligator, bare-handed! David Peters saw the alligator grab his dog. Without giving it a thought, he lunged at the alligator, which was twice his length and a whole lot stronger. The alligator, not one to let it pass, bit the boy’s right arm. As it happened, the boy had more friends on shore than the alligator had in the water. A few of David’s friends pulled him free. The pup got quickly ashore. David healed. So unless you were rooting for the reptile, the story has a happy ending – better than anyone who attacks an alligator has a right to expect! Make a list of some reasonable safety guidelines for people who live in alligator country.
Salt Marsh or Suburb Cities are expanding and merging. They are blurring into a megalopolis, one huge city. Sometimes, as cities and suburbs expand, they grow over and destroy coastal salt marshes. Salt marshes, protected as they are by dunes and beaches, are especially important. They are the nurseries for many species, including valuable fish and shellfish. Their destruction could forever alter life in the sea. Often, people must make a choice: salt marshes or suburbs. What alternatives to the “inevitable” expansion of suburbs into salt marshes and other natural areas can you think of?
Forest of Giants Off of California’s Channel Islands lies an underwater forest of giant kelp. Macrocysts, the largest of all seaweeds, can reach 150 feet and may grow as much as 2 feet a day! Macrocysts and the slightly smaller elk kelp form dense, tangled forests in these waters. It’s a fluid world of light and shadow, a special ecosystem. Phytoplankton pastures are grazed by microscopic herbivores and hunted by tiny predators. The kelp forests nourish complex food chains of sea urchins, abalone, sea hares, and octopuses. At the top of the food chain are seals and sea lions, and the ultimate predator, the great white shark. A single kelp may support half a million organisms. Describe the effects destroying most of the kelp forest would have an other organisms.
Staff of Life Why do we sometimes call money “dough?” Why do we call the family money-maker the “breadwinner?’ Our economy runs on money. But not long ago, someone with a smidgen of cheese, some herbs, and a slab of bread was considered prosperous. Throughout history, bread has been the staple food of the western world. Bread is made of what, oats, rye, or any rain that is tasty, nutritious, and abundant. Whether homemade or bought with coin of the realm, bread expresses the baker’s pride and reflects the baker’s culture. Small wonder, then, that brad and dough became synonymous with money. Bread is the staff of life. What ingredients are fond in bread, aside from the primary grain?
Swimmer’s Itch “I’m all itchy,” the little girl complained, as she and her brother splashed ashore. Their mother toweled her down, but the boy scooted off and let the sun dry him. Both children showed symptoms of swimmer’s itch: quarter-inch raised spots on their skin. The boy had larger blotches and more of them. He was running a fever by evening. Over the next two weeks, both children recovered completely. What happened? Parasitic flatworms cause swimmer’s itch. The worms mistook the children for their usual host, water birds. The parasites mature and breed in the birds’ intestins. The eggs leave with the birds’ feces to ripen and hatch in freshwater. Free-swimming larvae find another host, a snail. Later, they exit and swim frantically about seeking waterfowl. Occasionally, the parasites encounter human skin and burrow in. That’s what causes swimmer’s itch. How did the mother’s behavior reduce the little girl’s reaction?
What Are The Chances? The planet, a scant 8,000 miles in diameter, wobbles slightly in its orbit around a mediocre star. Land – barren and geologically active-takes up less than a quarter of its surface. The rest is a sterile sea. The atmosphere is a foul mixture of ammonia, methane, and steamy fog. There is no free oxygen. Volcanoes spew lava and ash. Lightning flashes from horizon to horizon. Radiation from the nearby star sears the planet’s surface. This planet is Earth, just before life began. What Internet search terms would you use to research the origin of life on Earth?
Something About Kicking Cats Teachers often assign students to memorize the major taxa: kingdom, phylum, class, order, family, genus, and species. At first, because the unfamiliar words make no sense, they’re difficult to memorize. “Kick poor cat off fair grounds Saturday.” What does this sentence have to do with memorizing the seven taxa: the sentiments are unworthy; the grammar is poor. But it makes enough sense to be memorable, and it will help you remember the taxa. Compare the seven taxa with the sentence, and you’ll see that each word on the list begins with the same letter as each word in the sentence. Once you have the sentence memorized, you’ll have no trouble memorizing the list. A mnemonic is a memory trigger or aid. Come up with a mnemonic sentence to help you remember a biology list you have to memorize. Share your list and the mnemonic with your class.