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Louisiana 7 Science iLEAP TM TABLE OF CONTENTS Introduction ....................................................................................................................... 1 Tips for Taking Science Tests ......................................................................... 1 Unit 1 – The Nature of Science ................................................................................... 3 Review 1: Thinking Like a Scientist ............................................................. 4 Benchmarks/GLEs: SI-M-A1/3; SI-M-A4/10; SI-M-A5/14–16; SI-M-A6/17, 18; SI-M-A7/21; SI-M-A8/23, 24; SI-M-B1/25–27; SI-M-B2/28; SI-M-B4/33; SI-M-B5/34–37 Review 2: Planning and Conducting an Experiment.......................... 18 Benchmarks/GLEs: SI-M-A1/1, 2; SI-M-A2/4, 5; SI-M-A3/6–8; SI-M-A4/11–13; SI-M-A7/20, 22; SI-M-B2/28; SI-M-B3/31; SI-M-B5/36 Review 3: Communicating and Understanding Data ........................ 38 Benchmarks/GLEs: SI-M-A3/8, 9; SI-M-A4/11; SI-M-A7/19; SI-M-B3/32 Review 4: Science, Technology, and Society.......................................... 59 Benchmarks/GLEs: SI-M-B3/29, 30; SI-M-B6/38; SI-M-B7/39, 40 Unit 2 – Properties of Matter .................................................................................... 69 Review 5: Physical Properties of Matter .................................................. 70 Benchmarks/GLEs: PS-M-A1; PS-M-A4; PS-M-A5 Review 6: Chemical Properties of Matter................................................ 79 Benchmarks/GLEs: PS-M-A1; PS-M-A2; PS-M-A3; PS-M-A6; PS-M-A7; PS-M-A8; PS-M-A9/1 Unit 3 – Life Sciences .................................................................................................... 91 Review 7: Cell Structure and Function..................................................... 92 Benchmarks/GLEs: LS-M-A1/2, 3; LS-M-A2/4; LS-M-A4/7, 8; LS-M-B1/15 Review 8: Human Health ........................................................................... 109 Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Review 9: Reproduction and Heredity.................................................. 127 Benchmarks/GLEs: LS-M-B1/14, 15; LS-M-B2/16–18; LS-M-B3/19–22 Review 10: Adaptations for Survival ...................................................... 143 Duplicating any part of this book is prohibited by law. Benchmarks/GLEs: LS-M-D1/30, 31; LS-M-D2/32–34 Review 11: Life Cycles of Plants and Animals ..................................... 164 Benchmarks/GLEs: LS-M-A3/5, 6 Unit 4 – Environmental Science ........................................................................... 177 Review 12: Ecosystems ............................................................................... 178 Benchmarks/GLEs: LS-M-C1/23; LS-M-C2/24; LS-M-C3/25, 26; LS-M-C4/27–29; SE-M-A1/36; SE-M-A2/37, 38; SE-M-A5/40 Review 13: Protecting Ecosystems and the Environment ............. 199 Benchmarks/GLEs: SE-M-A1/35, 36; SE-M-A2/37, 38; SE-M-A3; SE-M-A4/39; SE-M-A6; SE-M-A7/41, 42; SE-M-A8/43; SE-M-A9; SE-M-A10 iii Table of Contents Appendix......................................................................................................................... 217 Glossary ........................................................................................................... 219 Word Links ...................................................................................................... 229 Benchmark and GLE codes are listed for each review in the table of contents and for each page in the shaded gray bars that run across the tops of the pages in the workbook (see example to the right). These codes indicate which Benchmarks and GLEs are covered in a given review or on a given page. Unit 3 Standards: A1, B2, C3 100 iv Duplicating any part of this book is prohibited by law. To the Teacher: Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7 /13 Review 8 Human Health Your body is complex; it is made up of many different parts and systems. Some of these systems you can control. For example, you can choose whether to eat a piece of bread or a candy bar. However, many of your body’s systems are self-controlled. Whatever you choose to eat, once the food gets into your mouth, your body starts taking over, as though it were on autopilot. Your tongue makes saliva to break down some of the food. Muscles in your throat push the food down to your stomach. Your brain tells your stomach to make acid that turns the food to slush. Your intestines soak up nutrients from that slush, the nutrients your body needs to keep working. Your blood, pushed and pulled along by your heart, carries these nutrients all around your body. Any wastes from the body and anything left over is handled by your kidneys, your liver, and your colon. You cannot control most of these processes. They are automatic. It’s a good thing your body does all these things by itself. If you had to think about doing all this stuff, you’d be making thousands of little choices every minute of every day just to stay alive. You wouldn’t have time to talk to friends, listen to music, read a book, or go have fun on a Friday night. You couldn’t even sleep, because your mind would have to stay awake to tell your body how! Above: Your body is complex and made up of many different parts and systems. Duplicating any part of this book is prohibited by law. This review is all about the systems that keep your body running without you even thinking about them—all the systems that leave you free to think about things like school. Words Words to Know to Know alveoli antibiotics antimicrobial agents artery blood bone capillary cartilage diaphragm esophagus excretory system heart homeostasis infectious diseases intestine joint lungs noninfectious diseases organ organ systems parasite pathogen plasma puberty red blood cells stomach tissues trachea vein vertebrates villi white blood cells 109 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9,10; LS-M-A6/11,12; LS-M-A7/13 Word Links Look at the “Words to Know” list on the previous page. Circle two words that you don’t know or that you want to learn more about. Then, on a separate piece of paper, write each word and what you think each word means. Tissues, Organs, and Organ Systems The descriptions in this review focus on the human body. However, much of this description also applies to many vertebrates—animals with backbones. Vertebrates include fish, amphibians, reptiles, birds, and mammals. The most basic complete structures in the body are cells. Cells that do the same job work together to form body tissues. Each tissue is made of a specific type of cell that has a particular function. For example, muscles are tissues. Muscles are made of muscle cells. Their job is to contract and relax, making the body move. Groups of tissues, sometimes with specialized functions, make up organs. Organs have specific functions in the body that are usually unique, like the liver. Sometimes organs come in pairs, like the lungs and kidneys. Organs, in turn, work together in organ systems. These are groups of organs that accomplish some goal. For instance, the heart, the blood, and the blood vessels work together to form the circulatory system, the body’s transit system. Each function that humans and most other animals must do to stay alive (breathing, eating, thinking, etc.) is made possible by groups of specialized cells arranged into tissues, organs, and organ systems. What is the difference between an organelle and an organ? Now let’s look at some of the organ systems at work within the human body. 110 Duplicating any part of this book is prohibited by law. Place the following in order from least complex to most complex: organ, organ system, organelle, tissue, cell, vertebrate. Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 The Skeletal System The skeletal system is made up of the different bones of the body. Bones vary tremendously in their size and shape, depending on their function. For example, the bones in your legs are long, straight, and circular. Your ribs, on the other hand, are curved and flat. The skeletal system has many functions. For example, some bones protect organs. The bones in your skull protect your brain; the bones of your rib cage protect your heart and lungs. The skeletal system is also important because it provides support for the body. Explain what this means. The skeletal system helps your body move. To see how this is, bend your arm at the elbow. This movement is possible because the bones of your arm, like all bones in your body, are connected by joints. Many joints in the skeletal system are lined with cartilage. Cartilage is a soft, flexible, smooth tissue. It lets the joints slide past each other easily. It also cushions and protects the ends of bones during movement. The skeletal system contains many joints. Identify two joints other than your knee joint. Joint 1: Joint 2: Duplicating any part of this book is prohibited by law. What kinds of movements do the joints you identified produce? Knee Joint femur joint cartilage tibia Above: Cartilage allows the joints to slide past each other and cushions and protects the ends of bones during movement. Arthritis is a condition in which the cartilage in a joint has worn away. What happens to a joint that is no longer cushioned and covered by cartilage? 111 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 The Circulatory System The circulatory system consists of the heart, blood, and blood vessels. This system is the body’s delivery service. It provides all tissues in the body with oxygen and nutrients. It is also the trash collection system because it removes waste products, such as carbon dioxide. Blood The heart acts as a pump that keeps blood moving through blood vessels. Blood is a thick liquid that transports nutrients and wastes. Blood is made of three main components. r Plasma: Over half of your blood is made of plasma, which is mostly water. r Red blood cells: These blood cells transport oxygen throughout the body. r White blood cells: These blood cells help fight infections. Vessels Vessels transport blood throughout the body. There are three types of blood vessels. r Arteries carry blood away from the heart. r Veins carry blood toward the heart. r Capillaries are tiny vessels that join arteries and veins and reach all cells of the body. Capillaries can be thinner than a single strand of hair. Blood travels to the lungs, where red blood cells pick up oxygen. The red blood cells carry this oxygen to other parts of the body. Blood also travels to the digestive system, where nutrients from food are absorbed into the bloodstream and distributed to other tissues. artery to lungs vein from lungs artery vein KEY = Oxygen-rich blood capillaries 112 = Oxygen-poor blood Duplicating any part of this book is prohibited by law. Human Circulatory System Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Willy claims that arteries carry oxygenated blood and veins carry blood with carbon dioxide. Is this correct? Explain your answer. When you exercise, your heart beats much faster than when you sit still. Explain why physical activity causes this to happen. Duplicating any part of this book is prohibited by law. Which blood vessels, arteries, veins, or capillaries, contain blood at the highest pressure? Explain your answer. 113 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 The Respiratory System The respiratory system works closely with the circulatory system to provide the body’s tissues with oxygen and to remove carbon dioxide from the body. The respiratory system controls respiration, or breathing. You may remember respiration from a previous review. The same word is used for breathing and for the process of breaking down sugars, because animals breathe in order to exchange the gases used in cellular respiration. When you inhale, a thin muscle called the diaphragm contracts. When this happens, your lungs, which are like big sacks or sponges, expand to hold air. When the diaphragm relaxes, it helps squeeze the air back out of your lungs. Air enters mostly through the nose. The nose is full of tiny hairs that filter dust from the air. Air then travels to the trachea, a hollow tube that carries air to the lungs. Once in the lungs, the air travels to tiny air sacs called alveoli. Oxygen diffuses over membranes in the alveoli, entering the blood. Red blood cells grab on to the oxygen and take it away in the bloodstream. At the same time, carbon dioxide diffuses into the lungs. When you exhale, the carbon dioxide–rich air travels back up the trachea and out through the nose or mouth. Human Respiratory System nose alveolus trachea capillary diaphragm Look at the diagram above. What do the arrows going between the alveolus and the capillary represent? At high elevations, like in the mountains, less oxygen is in the air than at sea level. If you traveled to the mountains, what effect would it have on your respiration? Explain how this relates to diffusion. 114 Duplicating any part of this book is prohibited by law. lungs Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 The Digestive System The digestive system provides your body with the nutrients you need to survive. These nutrients come from the food you eat. The process of breaking down food begins in the mouth. When you chew, your teeth break down food physically. Your saliva begins breaking it down chemically. The food is then swallowed and travels through the esophagus, a long tube that connects the mouth to the stomach. Once in the stomach, food is broken down even more by stomach acid. The food then travels from the stomach to the intestine. The intestine is a long, snakelike tube coiled just below your stomach. In fact, when stretched end-to-end, an adult intestine is over 7 meters long! The intestine is divided into two parts, the small intestine and the large intestine. Nutrients from food are absorbed into the blood in the small intestine. Anything that is not absorbed is carried to the large intestine. The large intestine removes water from leftover food and stores the waste until it is expelled from the body. Human Digestive System mouth esophagus stomach large intestine small intestine Duplicating any part of this book is prohibited by law. In what ways are the digestive system and the respiratory system similar to each other? Why do you think the small intestine needs to be so long? 115 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Organ Systems Working Together Organ systems do not function alone. All the systems are needed to make a functioning human body. Several groups of systems work closely together to maintain balance within the body. The heart, blood, and blood vessels make the circulatory system. The nose, mouth, trachea, and lungs make the respiratory system. What is the relationship between the two systems? To get energy from food nutrients, all cells need a constant supply of oxygen. The process that releases this energy also makes carbon dioxide, which is toxic to humans. Our bodies must constantly breathe in new oxygen and breathe out carbon dioxide. (This relationship with breathing is why the process of breaking down food energy is known as respiration.) The circulatory and respiratory systems work together to exchange gases with the outside environment and distribute them throughout the body. Organ systems often work in larger groups. The circulatory system, as the conveyor belt of the body, is responsible for moving nutrients to cells, too. In order to do this, it works closely with the digestive system to pick up nutrients from the villi in the small intestine and bring them to the cells. At the same time, this cycle would not be complete without the oxygen from the respiratory system and also a fourth system, the excretory system. This system is responsible for removing cellular wastes and excess water from the body. This system, too, relies on the circulatory system for transportation and relies on the digestive system for the nutrients to power itself. Ultimately, every system in the body depends on all the others. They must all function together, or the body as a whole will not work properly. List two more examples of body systems that work together. Explain how they need each other to do their own jobs properly. People do not go through metamorphosis, like insects. However, we still experience tremendous change as we grow and develop. Infancy and Childhood Humans’ most distinctive feature is our intelligence. Our brains are so large that we are born before they finish developing. As a result, human newborns are completely helpless. They cannot walk, crawl, or communicate. However, over the first few months and years, humans develop dramatically. By six to ten months, they are usually crawling. They say their first words at around one year old and speak in complete sentences by age three. Throughout childhood, children’s brains have one major task: learning. 116 Above: Over the first few months and years, humans grow and develop dramatically. Duplicating any part of this book is prohibited by law. Growth and Development of Humans Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Puberty The puberty phase begins around ages 8 to 14. Pubescent people experience growth spurts, where their overall physical size increases very rapidly. As puberty continues and the child becomes a teenager, many other changes occur. Pubescent people begin to experience sexual attraction to others. They often experience very strong emotions, without the life experience to control those emotions. Puberty can be a difficult time. However, it does end, usually by the early twenties. Describe two major changes between childhood and puberty. Above: Puberty begins around ages 8 to 14, a time when many emotional and physical changes occur. As people age, their basic abilities (like memory and physical strength) tend to decline. What advantages make up for these changes? Explain. Duplicating any part of this book is prohibited by law. Adulthood and Old Age Adult humans experience a gradual decline as they move toward old age. Although their thinking often becomes more sophisticated due to increased life experience, their basic abilities, both physical and mental, slowly decrease. As we age, we lose muscle mass and sometimes find it more difficult to remember things or pay attention. We also begin to develop soreness and aches. We may develop age-related symptoms, such as hearing loss, vision loss, or arthritis. Many of these problems can be moderated through mental or physical exercise. By constantly using the basic faculties, we can help slow or reverse age-related decline. Diseases become more and more common as we age. Above: Many of the problems associated with aging can be moderated through mental or physical exercise. 117 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Influences on Human Health Everyone gets sick sometimes. No one remains young and healthy forever. However, some people are healthier than others. There are many influences on human health. Although many of these are out of our hands, we can control others. It is important to make good decisions in order to stay healthy. Genetic Factors Some people are predisposed to illness. Some people have family histories of diseases, such as heart disease, depression, or cancer. Genetic factors make some people gain more weight than others. Sometimes entire groups of people are more prone to certain illnesses. For example, African Americans are more likely to have high blood pressure, so doctors advise that they eat less sodium. Genes can even cause specific diseases. Maintenance Our decisions greatly impact how healthy we are and how good we feel. Many little decisions will help us lead healthier lives. For example, washing our hands regularly, especially after using the restroom and before preparing food and eating, will help prevent germs that cause colds. Brushing and flossing will help avoid painful dental problems. Toxins We can make important choices about what we put into our bodies. Many chemical substances can cause diseases, like cancer or heart disease. Nicotine and other substances in cigarettes cause cancer, strokes, and heart disease. Excessive alcohol consumption can cause damage to the heart, liver, and brain. Illegal drugs can have dangerous effects, including addiction, hallucinations, psychosis, and sudden death, in addition to many of the threats associated with cigarettes. Many people choose to use these toxic substances. As with diet and exercise, people who make good choices lead happier, healthier, longer lives. 118 Duplicating any part of this book is prohibited by law. Two of the most important choices to protect our health are our choices about nutrition and exercise. Good nutrition helps prevent diseases of all kinds and helps to control weight. Nutrition advice changes frequently. However, the constants seem to be that we should eat a balanced diet with many green and leafy vegetables, limit the amount of meat we eat, and get protein from beans and dairy products. In general, most Americans eat too much and exercise too little. Exercise is wonderful for the body. Studies have shown that exercise helps us prevent many kinds of illness and stay both strong and flexible as we age. Exercise even helps preserve good brain function. People who exercise more are less forgetful, more focused, and less likely to suffer depression and age-related mental decline. Perhaps most important of all, people who exercise regularly tend to feel better than people who do not. Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 How are genetic factors different from the other influences mentioned here? Choose two decision that people can make to improve their health. Describe the advantages of each choice. Disease Everyone gets sick sometimes. Disease is a disruption of the natural body balance, or homeostasis. Diseased body systems fail to work properly or at all. Some diseases cause the heart or kidneys to stop working. Others may cause serious tissue swelling, muscle weakness, or severe confusion. Many things can cause disease. However, public health professionals talk about two main kinds of disease: infectious and noninfectious. Duplicating any part of this book is prohibited by law. Infectious diseases can be spread from one person to another. They are caused by pathogens. A pathogen is an organism or virus that causes disease in another organism. Common pathogens include bacteria, viruses, fungi, and protists. Parasites are a special kind of pathogen. They are multicellular. All pathogens find homes inside the host body and begin multiplying, sickening the hosts. Different diseases are caused by different pathogens. For example, the common cold, mumps, and warts are caused by different viruses. Athlete’s foot is a fungal infection. Sinus infections and strep throat, however, are usually caused by different bacteria. Thousands of pathogens can infect and damage the health of organisms. Many can be very severe. Diseases, such as human immunodeficiency virus (HIV) or the Ebola virus cause lifethreatening diseases. Bacteria can cause lung infections, stomach flu, and other problems. Fungi often attack the skin and respiratory system. For example, gardeners are often exposed to a fungus named Histoplasma capsulatum. This fungus, common in chicken droppings used as gardening manure, can cause coughing, lung congestion, fever, chills, etc. Parasites can also cause gruesome and deadly infections. For example, tapeworms reside in the digestive system and other parasites enter the heart, lungs, and liver. How Infectious Disease Spreads Diseases that spread from one organism (the carrier) to another are contagious. Some diseases are more contagious than others. Some spread only through direct physical contact. Others spread by sharing objects, by sharing food or drink, or even through the air. 119 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 For example, imagine borrowing a pen from someone who has a cold. If some of the virus is on the person’s pen, you may get it on your hands when you hold the pen. If you then wipe your nose with your hands, you may catch the cold. Why does washing your hands reduce your risk of catching a cold? Pathogens may also be spread through vectors, which are animals that carry the disease. The vector may or may not show symptoms of the disease. For example, the West Nile virus is often fatal to birds, but it is carried by mosquitoes that suffer no symptoms. The mosquitoes are a vector that spreads the virus from bird to bird (or from bird to human). Fighting Disease-Causing Pathogens A growing problem with antibiotic use is antibiotic resistance. Suppose a person is given an antibiotic to treat a bacterial infection. The antibiotic will kill most of the bacteria, but a few bacteria may have a genetic trait that lets them survive. These survivors multiply or share their genes with other bacteria. As a result, populations of bacteria begin to have various levels of resistance to the antibiotic. An “arms race” develops, as doctors need larger doses of existing antibiotics, combinations of antibiotics, or even more powerful new drugs to combat the resistant bacteria. Meanwhile, the bacteria may become resistant to new antibiotics as well, leading to potentially uncontrollable infectious diseases. A doctor tells a patient to take an antibiotic for six days. After three days, the patient feels better and stops taking the antibiotic. Give two reasons why the person should take the antibiotic for the full six days. 120 Duplicating any part of this book is prohibited by law. How do science and technology fight the spread of disease caused by pathogens? Antimicrobial agents are chemicals that stop microbe (single-celled organism) growth or destroy microbes. Common antimicrobial agents produced by technology include bleach, hydrogen peroxide, and iodine. Antimicrobial agents produced by microorganisms are called antibiotics. For example, the mold Penicillium notatum makes a chemical that can kill several types of bacteria. Scientists isolated this chemical in the 1930s, producing the first antibiotic treatment for disease, penicillin. Today, many other antibiotics are available. They stop bacteria in different ways. Some antibiotics keep bacteria from producing their proteins; others damage bacteria cell membranes. Antibiotics do not attack the cells of multicellular organisms, and they do not affect viruses. Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Noninfectious diseases cannot be passed from one person to another, but they can still cause great harm. Some noninfectious diseases are genetic. People are either born with them or have a high chance of developing them. The disease called cystic fibrosis is a genetic disease. Other noninfectious diseases come from mutations inside the body. Cancer, for instance, is caused by mutations in cells. The mutations allow the cells to divide very fast and stop cooperating with the tissue they live in. Cancerous cells form large masses called tumors. Individual tumor cells, or clumps of cells, can break away and spread through the bloodstream to other parts of the body. These cells then grow into new tumors at their new sites. Due to genetics, some people have an increased risk of developing some types of cancers. Why would the daughter of a woman with breast cancer want to have regular exams to check for cancer? Other kinds of noninfectious disease are called lifestyle diseases. These come from maltreating the body. Smoking cigarettes is a prime example. Smoking increases the risk of a person developing lung cancer. Much of the cure for this and other lifestyle diseases involves changing personal habits—and changing societies so that healthy personal choices are easier to make. What social changes might make it easier for people to avoid cigarette smoke? Duplicating any part of this book is prohibited by law. Mistreatment of the body does not always come from lifestyle choices. Exposure to toxic chemicals, like lead and mercury, can seriously disrupt many life processes and even kill. We continuously monitor the environment for these causes of disease. Finally, the causes of some diseases are still largely mysteries to us. We do not know, for instance, what causes asthma, a lung disease that makes breathing difficult. It may be caused by genetic factors, or it may be caused by infection or environmental factors. Perhaps it is caused by all three. We do not understand the causes of many mental illnesses. Medicine has made great strides in the last hundred years. As a result, we live twice as long as we used to. However, there is still a great deal we wish to learn about diseases and health. 121 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Word Links Now that you’ve read through this review, go back to the words you circled in the “Words to Know” list. Write each word in the “Word Links” table at the back of this workbook. Fill out one row for each word. Keys to Keep Humans are made of many organ systems, which are made of organs. Organs are made of tissues, which are collections of cells. Like animals, people grow and develop over time. Human health requires people to be careful and make good choices. Diseases are caused by many factors but mainly by invasive microorganisms. Have you ever heard of the dance called the Peabody? Luckily for Candace Pert, she had. She was at a party when a man asked if anyone knew how to do that dance. Because Pert and her husband knew the Peabody, they joined the man on the dance floor. Afterward, the three began talking. Pert mentioned that she wanted to study the chemicals of the human brain to learn more about how they make the brain work. She lived close to a university in Maryland where a man named Dr. Sol Snyder was studying these things. Pert wanted to earn her Ph.D. working with him, but the university had rejected her application. The man at the party happened to be a good friend of Snyder, and he promised to talk to the brain researcher. Pert wrote a letter telling about all her scientific goals, and, a short time later, Snyder called to tell Pert that she had been accepted to the university. Pert now has become a famous scientist and has made some important discoveries about how the brain works. She is also an author, a mother, and a pretty good dancer. Candace B. Pert (United States 1946–) 122 Duplicating any part of this book is prohibited by law. People in Science Review 8: Human Health Benchmarks/GLEs: LS-M-A5/9, 10; LS-M-A6/11, 12; LS-M-A7/13 Explore It Yourself The following simulation will give you a better sense of how microbes spread. The year is 1350, and your classroom is a town in plague-ridden Europe. Your town has not been struck with the dreaded disease, but three seemingly healthy merchants have just arrived. They bring news of the plague, and everyone is eager to hear it. (At this time in human history, nobody knew about microbes or how contagious diseases spread.) Your teacher has three piles of paper squares. Each pile is a different color, and each color represents a different type of microbe. Step 1: Your teacher chooses three students to be the merchants new to town. Each merchant comes to the front and picks up one pile of paper. Step 2: Each merchant picks two townspeople to hear news of the plague. Those townspeople come up front to greet the merchant that chose them. Step 3: Each merchant keeps one square and gives five squares to each townsperson he or she picked. Step 4: The townspeople with five squares now choose two more townspeople with whom to share the news. These new townspeople come up to hear the news from the person that chose them. Step 5: Each townsperson with five squares keeps one square and gives two squares to each person he or she picked. Step 6: Each townsperson with two squares chooses one person who hasn’t yet heard the news and gives that person a square. Duplicating any part of this book is prohibited by law. Step 7: By now, all of the squares should be distributed. Any leftover squares should be placed onto the teacher’s desk. Step 8: Everyone returns to their homes (their seats). Step 9: Record the number of people holding each color of square: Purple: Green: Blue: Step 10: Your teacher reveals the identity of each colored square and the effects of having that type of bacterium or virus. 123 Unit 3 – Life Sciences Benchmarks/GLEs: LS-M-A5/9-10; LS-M-A6/11-12; LS-M-A7/13 1. Explain how the plague in this simulation was spread. 2. Why were some people able to avoid getting the plague? 3. All the people in this town became infected with either a type of bacterium or a virus. Why did some people live and others die? 4. Today, we know that rats carry the bacteria that cause the plague. Fleas bite both rats and people. Use your knowledge of vectors to explain how fleas helped to spread the plague. 5. Scientific understanding and technological treatment of contagious disease have advanced since 1350. Describe two advancements in how humans understand and treat contagious diseases. 124 Louisiana iLEAP Science Practice begins on the following page. Duplicating any part of this book is prohibited by law. What Does It Mean? Review 8: Louisiana i LEAP Science Practice i LEAP Science Practice 1. 2. Duplicating any part of this book is prohibited by law. 3. 4. Where does chemical digestion first begin? A. in the stomach B. in the mouth C. in the esophagus D. in the large intestine When humans breathe, oxygen travels through the respiratory system into the bloodstream. Where does this occur? A. in the diaphragm B. in the nose C. in the trachea D. in the lungs Which statement best describes capillaries? A. Capillaries are larger than arteries. B. Capillaries carry blood back to the heart. C. Capillaries are smaller than arteries. D. Capillaries carry only white blood cells. Which of these helps to slow the effects of aging? A. exercising regularly B. avoiding all alcohol C. drinking lots of water D. brushing teeth regularly Louisiana i LEAP Science Practice 125 Review 8: Louisiana i LEAP Science Practice 5. 6. What is the most effective way to prevent the most common diseases? A. avoiding risky sexual behaviors B. taking antibiotics when feeling ill C. getting enough exercise regularly D. frequently washing your hands Examine the image below. X 7. Cancer and rheumatoid arthritis are two diseases in which the body’s normal functions stop working. Cancerous cells reproduce uncontrollably, which damages the body’s function and often causes death. In rheumatoid arthritis, the body’s immune system attacks the cartilage, which normally protects joints. This causes pain, bone loss, and loss of mobility. A. Compare these two diseases. How are they similar? Consider factors, such as severity, length of disease, and whether or not they are contagious. B. Name three diseases that are different from cancer and rheumatoid arthritis. Describe how these diseases are different. Consider the same factors you mentioned in the previous question. W Z Which structure in the figure helps cushion bones during movement? 126 A. W B. X C. Y D. Z Louisiana i LEAP Science Practice Duplicating any part of this book is prohibited by law. Y