How are bacteria becoming resistant to antibiotics? The Story:

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1 How are bacteria becoming resistant to antibiotics? In the 1950 s and 1960 s, scientists and doctors began to learn about vaccines, antibiotics, and other medicines which could treat the world s deadliest epidemics. Diseases such as polio, smallpox, rubella, measles, mumps and malaria which, at the time, were lethal and widespread suddenly disappeared from the vast majority of the planet. For decades, scientists believed the world would never again be attacked by these bacteria and viruses thanks to advancements in medicine. Yet in the last 20 years, hospitals and pharmacies around the world have noticed that the same medicines which used to kill the pathogens that caused these diseases are no longer working. Why is it that bacteria have suddenly become resistant to antibiotics?

2 Are Tasmanian devils fighting off the devil facial tumor disease? A horrific disease has been making its way through the Tasmanian devil population since It s called Devil Facial Tumor Disease, and it causes cancerous lumps and legions to form on the Tasmanian devil s faces. Some lumps are so large they prevent the animal from seeing or being able to open its mouth to eat. DFTD is unique because it is one of the only contagious cancers that have ever been discovered. Thankfully to humans, only the devils can get the disease. For a while, it looked as if the disease was going to cause the extinction of the devils (as many as 90% of the species had been wiped out). Recently, though, the fears that extinction might occur have been alleviated by the devils themselves. Scientists noticed that the devils are beginning to breed earlier. Normal age for females to have their first litter is 2 years old but, in the past decade, they have started giving birth at age 1. This allows the animals to breed before the cancer has a chance to set in. They aren t beating cancer, but they are preventing their population from going extinct. How did this sudden change in biology happen?

3 Did blue mussels in Massachusetts learn a new defense strategy? In 1993 somehow the shores of Massachusetts were invaded by an exotic, nonnative species, the Asian shore crab. The main food source the crabs chose to feed on were the native blue mussels. Blue mussels do not have any natural defense mechanisms other than a shell, which the crabs easily tear apart. But in August 2006, the University of New Hampshire announced that the newborn blue mussels had been growing thicker shells. So thick, even, that the crabs were unable to pry through the shells to get to the soft meat underneath. To test the theory that the mussels were evolving, scientists collected specimens of blue mussels that lived further north, on the coast of Maine. The blue mussels of Maine routinely thickened their shells when a predator was in the vicinity. The Asian shore crabs had yet to travel as far north as Maine though, and so these mussels had never had any contact with the crabs and therefore did not know they were a predator. They separated the Maine mussels into three groups: group A would be placed in an environment with no predator; group B would be placed in an environment with a familiar predator, the New England green crab; group C would be placed in an environment with the unfamiliar predator, the Asian shore crab. After three months, the mussels from Maine had grown thicker shells when placed with the predator they were familiar with but the other groups hadn t. So what does this prove about the Massachusetts mussels, and why did they start growing thicker shells?

4 How did Lake Victoria get so many species of cichlids? Lake Victoria in East Africa is home to around 500 species of cichlids, a family of small, colorful fish. Each of the cichlid species in the lake live harmoniously with the other fish species. Interestingly, each species spends its entire life at a specific depth in the lake. For example, osceollatus cichlids live around 80 feet below the surface, while flowerhorn cichlids live closer to the surface at a depth of 5 feet. As light passes through water, the water causes the wavelengths of light to break apart. This is why in deep pools, water appears clear near the surface, bluer after a few feet of depth, and black near the bottom. The wavelength of light changes as the water depth changes. It is known that each species of cichlid is able to see only a small range of light and, thus, will live at the depth of water in which they can best see. Since Lake Victoria is closed off to other fish species, how did one species of cichlids evolve into more than 500 species, each one identifiable by the depth at which it lives?

5 Is the sport of hunting forcing an evolution? Anyone who hunts, fishes, or knows someone who does understand the type of animals always bragged about: large, numerous antlers on deer and elk, claw and jaw length on bears, salmon and steelhead so big they take hours to reel in, etc. For the first time in history, the number of humans who hunt for fun outnumber those who hunt out of need for food. Trophy animals aren t always the best animals for food though, which means the animals being hunted are different today than the animals 100 years ago. Scientists have noticed that big game, such as moose, boar, and halibut, are progressively growing smaller and smaller in size every year. The smaller the animal, the more likely the hunter will choose to let live or the fisher will choose to throw back. How have these animals learned or changed their biology to make themselves smaller?

6 How did the blue-moon butterfly save itself from Wolbachia annihilation? In Samoa, a bacterial parasite, most likely Wolbachia, depleted the population of the beautiful blue moon butterfly. The parasite targeted male butterflies and, by 2001, only 1% of the overall population was male. The species was hardly spotted again over the next few years and was believed to be on the path for extinction. Then in 2007 a butterfly census on the island revealed the number of males in the population had risen from 1% six years earlier to 40%. Not only that, but the new male population had built immunities to protect themselves against the Wolbachia parasite. What had happened to the population of male blue moon butterflies that suddenly changed them from doomed to thriving?

7 Where did the big-legged frogs in Australia come from? Toxic Toads were introduced in Australia 80 years ago to help wipe out the beetle population that was destroying the farmlands throughout the continent. The hope was that the toads would consume enough of the beetles so that the crops would be protected, and the toads wouldn t compete with any other species since no one was consuming the beetles anyway. But now, toxic toads are being spotted in Australia hundreds of miles from where they were introduced years ago. And not only are the toads suddenly arriving, but the legs on these newfound toads are much larger than the legs of the frogs originally introduced into the population. How are new toad species, with larger legs, suddenly appearing on the Australian continent?

8 How did the skink lose its legs? Australia has a population of unique lizards called skinks. Skinks are related to lizards, eat like lizards, live like lizards, and in fact follow all typical lifestyle descriptions of lizards with one exception: some skinks have no legs. Like snakes, the skinks move by scooting individual sections of their body in rhythm, making it appear as if the skinks slither. With only a distant relation to snakes (they re both scaled reptiles), how and why did the skink lizard lose its limbs?

9 What caused the pill bug and pill millipede to look so similar? Whenever we encounter a small insect with segmented armor sections we typically call it a pill bug or rolley polley. It turns out that two common organisms with dramatically similar structures are entirely different classes of organisms. Pill millipedes are insects, as most people suspect. Pill bugs, however, are armadillidiidae and actually aren t insects: they re crustaceans, more closely related to crabs and lobsters than insects. Both have 9-15 segments, both segments have rounded armor made of chitin, and both are able to roll into a bundle for protection. Yet they are as dissimilarly related genetically as eels and salmon. How did they both develop similar structures and live in similar territories with no common ancestor between them?

10 Is the hoatzin evidence that dinosaurs evolved into birds? A common and growing argument on the reason for the extinction of dinosaurs is that while some simply evolved into modern-day animals. (Remember that dinosaurs encompass approximately 300 million years of Earth s history and at least 5 mass extinctions not all died the same way). Animals in the avian (bird) phylum are one of the two most common nominees (as well as reptiles) due to dinosaur skeletons resembling larger versions of modern day bird skeletons. One example that supports this theory is the hoatzin, a small, loud, showy bird that lives in northern South America. Hoatzin infants are born with a hand attached to their wings, including an opposable thumb and flexible first finger. While the claw disappears by the time the bird reaches adulthood, it s remarkably similar anatomically to dinosaur claw fossils. What is the implication of this claw, and what does it tell us about possible dinosaur evolution?

11 How did North America end up with a giraffe relative? A common, oft-seen member of the North American prairie is the pronghorn antelope. The term antelope is simply a nickname given by the locals and is in no way related to the antelope on the Asian and African savannas. The pronghorn is often assumed to be a cousin of the elk and deer that live in the same area. In reality though, according to a genetic comparison the closest living relative of the pronghorn antelope is not the deer of North America or the antelope of Asia it s the giraffe of Africa. How did an African land animal end up all the way in the middle of the North American continent?

12 Why did the palm nut vulture go vegetarian? The palm nut vulture is a large bird related to eagles. Most vultures are scavengers that eat carrion, or decaying material. This palm nut vulture, like their name suggests, has done something that no other bird in its family has done gone vegetarian. The bird lives in massive palm tree forests in Africa and feasts on the palm nuts produced by the tree. The digestive system of the bird processes the difficult, strong oils allowing the bird to get proteins and lipids not usually available except during digestion of meats. Nutrition-wise the bird is fine with either diet, so why did this one bird, in a population filled with animal prey, decide to go strictly herbivorous?

13 Biology Names Evolution Scenario Presentations Per For this project, you and your group will choose a scenario about an organism on our planet that has recently undergone an unusual series of changes. Are these changes evolution in action or something else? Tuesday-Thursday, March 7-9 th (Late Starts). Your group will receive one copy of an evolution scenario. As a group, read the scenario and go over your notes from the evolution unit. You and your group must try to narrow down a possible explanation (or explanations) you believe could explain the unusual situation. YOU DO NOT HAVE TO BE RIGHT; JUST BE ABLE TO JUSTIFY YOUR EXPLANATION. If you believe evolution is occurring, you must include either which Hardy- Weinberg condition has been broken. If you believe evolution is not occurring, you must explain how what is happening does not violate Hardy-Weinberg. Once you have decided, you must justify your explanation. Beginning in class on Friday and continuing until Monday, your group will have 3-5 minutes to present your argument to the class. Your argument will be in the form of a poster which you will build in class. The poster will take the following appearance: The Research Scenario Question: Your claim (Evolution and broken condition, or no evolution and why): Your evidence (Minimum 2) -Your evidence is the actual facts/data that back up your claim Your justification of the evidence (Minimum 2) -Your justification is an explanation of how the evidence on the left backs up your claim During the 3-5 minutes you will display your poster and explain the scenario, the question, and your claim. DO NOT JUST READ THE POSTER. You will then be asked a challenge question by one of the other groups (drawn at random) where you will defend your position. If your group is not paying attention during the presentation, you will not be able to ask a quality question. Also, if I deem your group is not paying attention I may require you to ask a challenge question as well. Remember: None of these scenarios have been proven yet, so there is no right answer. This is all about your ability to defend your position. We will draw names out of a hat for who will present first, unless we have volunteers. You will be scored based on the substance and style of your presentation. See the scoring rubric on the back of this page.

14 Names: Time (3-5 minutes). Less than 3 minutes = ½ credit for entire project All parts of the poster included and complete Persuasiveness of your claim and justification of evidence Ability to ask a quality challenge question that shows thought and comprehension Ability to respond to the challenge question respectfully and adequately All members speak an equal amount and can be heard Total (Lab Points) /10 pts /20 pts /50 pts

15 Names: Time (4-5 minutes). Less than 3 minutes = ½ credit All parts of the poster included and complete Persuasiveness of your claim and justification of evidence Ability to ask a quality challenge question that shows thought and comprehension Ability to respond to the challenge question respectfully and adequately All members speak an equal amount Total (Lab Points) /10 pts /20 pts /50 pts Names: Time (4-5 minutes). Less than 3 minutes = ½ credit All parts of the poster included and complete Persuasiveness of your claim and justification of evidence Ability to ask a quality challenge question that shows thought and comprehension Ability to respond to the challenge question respectfully and adequately All members speak an equal amount Total (Lab Points) /10 pts /20 pts /50 pts Names: Time (4-5 minutes). Less than 3 minutes = ½ credit All parts of the poster included and complete Persuasiveness of your claim and justification of evidence Ability to ask a quality challenge question that shows thought and comprehension Ability to respond to the challenge question respectfully and adequately All members speak an equal amount Total (Lab Points) /10 pts /20 pts /50 pts Names: Time (4-5 minutes). Less than 3 minutes = ½ credit All parts of the poster included and complete Persuasiveness of your claim and justification of evidence Ability to ask a quality challenge question that shows thought and comprehension Ability to respond to the challenge question respectfully and adequately All members speak an equal amount Total (Lab Points) /10 pts /20 pts /50 pts Names: Time (4-5 minutes). Less than 3 minutes = ½ credit All parts of the poster included and complete Persuasiveness of your claim and justification of evidence Ability to ask a quality challenge question that shows thought and comprehension Ability to respond to the challenge question respectfully and adequately All members speak an equal amount Total (Lab Points) /10 pts /20 pts /50 pts

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