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Latin B/C Third Declension Exercise
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Latin B/C Third Declension PracticeOwls, such as the young snowy owls on the previous page, have for centuries been symbols of both wisdom and mystery. To many cultures their piercing eyes have conveyed a look of intelligence. Their silent flight through darkened landscapes in search of prey has projected an air of power or wonder. For this chapter and this book, owls are an engaging example of a living organism from the world of biologyâthe study of life. BIOLOGY AND YOU Living in a small town, in the country, or at the edge of the suburbs, one may be lucky enough to hear an owl's hooting. This experience can lead to questions about where the bird lives, what it hunts, and how it finds its prey on dark, moonless nights. Biology, or the study of life, offers an organized and scientific framework for posing and answering such questions about the natural world. Biologists study questions about how living things work, how they interact with the environment, and how they change over time. Biologists study many different kinds of living things ranging from tiny organisms, such as bacteria, to very large organisms, such as elephants. Each day, biologists investigate subjects that affect you and the way you live. For example, biologists determine which foods are healthy. As shown in Figure 1-1, everyone is affected by this impor- tant topic. Biologists also study how much a person should exer- cise and how one can avoid getting sick. Biologists also study what CHARACTERISTICS OF LIFE The world is filled with familiar objects, such as tables, rocks, plants, pets, and automobiles. Which of these objects are living or were once living? What are the criteria for assigning something to the living world or the nonliving world? Biologists have established that living things share seven characteristics of life. These characteristics are organization and the presence of one or more cells, response to a stimulus (plural, stimuli), homeostasis, metabolism, growth and development, reproduction, and change through time. Organization and Cells Organization is the high degree of order within an organismâs internal and external parts and in its interactions with the living world. For example, compare an owl to a rock. The rock has a spe- cific shape, but that shape is usually irregular. Furthermore, differ- ent rocks, even rocks of the same type, are likely to have different shapes and sizes. In contrast, the owl is an amazingly organized individual, as shown in Figure 1-2. Owls of the same species have the same body parts arranged in nearly the same way and interact with the environment in the same way. Copyright © by Holt, Rinehart and Winston. All rights reserved. ORGANISM (Barn Owl) ORGAN (Owlâs Ear) TISSUE (Nervous Tissue Within the Ear) CELL (Nerve Cell) your air, land, and fAll living organisms, whether made up of one cell or many cells, have some degree of organization. A cell is the smallest unit that can perform all lifeâs processes. Some organisms, such as bacteria, are made up of one cell and are called unicellular (YOON-uh-SEL-yoo-luhr) organisms. Other organisms, such as humans or trees, are made up of multiple cells and are called multicellular (MUHL-ti-SEL-yoo-luhr) organisms. Complex multicellular organisms have the level of orga- nization shown in Figure 1-2. In the highest level, the organism is made up of organ systems, or groups of specialized parts that carry out a certain function in the organism. For example, an owlâs ner- vous system is made up of a brain, sense organs, nerve cells, and other parts that sense and respond to the owlâs surroundings. Organ systems are made up of organs. Organs are structures that carry out specialized jobs within an organ system. An owlâs ear is an organ that allows the owl to hear. All organs are made up of tissues. Tissues are groups of cells that have similar abilities and that allow the organ to function. For example, nervous tissue in the ear allows the ear to detect sound. Tissues are made up of cells. A cell must be covered by a membrane, contain all genetic information necessary for replication, and be able to carry out all cell functions. Within each cell are organelles. Organelles are tiny structures that carry out functions necessary for the cell to stay alive. Organelles contain biological molecules, the chemical compounds that provide physical structure and that bring about movement, energy use, and other cellular functions. All biological molecules are made up of atoms. Atoms are the simplest particle of an ele- ment that retains all the properties of a certain element. Response to Stimuli Another characteristic of life is that an organism can respond to a stimulusâa physical or chemical change in the internal or external environment. For example, an owl dilates its pupils to keep the level of light entering the eye constant. Organisms must be able to respond and react to changes in their environment to stay alive. ORGANELLE (Mitochondrion) BIOLOGICAL MOLECULE (Phospholipid) ATOM (Oxygen) cell from the Latin, cella meaning âsmall room,â or âhutâ Word Roots and Origins www.scilinks.org Topic: Characteristics of Life Keyword: HM60257 mb06se_bios01.qxd 5/18/07 10:37 AM Page 7 8 CHAPTER 1 Homeostasis All living things, from single cells to entire organisms, have mecha- nisms that allow them to maintain stable internal conditions. Without these mechanisms, organisms can die. For example, a cellâs water content is closely controlled by the taking in or releas- ing of water. A cell that takes in too much water will rupture and die. A cell that doesnât get enough water will also shrivel and die. Homeostasis (HOH-mee-OH-STAY-sis) is the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing. Organisms have regulatory systems that maintain internal conditions, such as temperature, water content, and uptake of nutrients by the cell. In fact, multi- cellular organisms usually have more than one way of maintain- ing important aspects of their internal environment. For example, an owlâs temperature is maintained at about 40°C (104°F). To keep a constant temperature, an owlâs cells burn fuel to produce body heat. In addition, an owlâs feathers can fluff up in cold weather. In this way, they trap an insulating layer of air next to the birdâs body to maintain its body temperature. Metabolism Living organisms use energy to power all the life processes, such as repair, movement, and growth. This energy use depends on metabolism (muh-TAB-uh-LIZ-uhm). Metabolism is the sum of all the chemical reactions that take in and transform energy and materials from the environment. For example, plants, algae, and some bacteria use the sunâs energy to generate sugar molecules during a process called photosynthesis. Some organisms depend on obtaining food energy from other organisms. For instance, an owlâs metabolism allows the owl to extract and modify the chemi- cals trapped in its nightly prey and use them as energy to fuel activities and growth. Growth and Development All living things grow and increase in size. Some nonliving things, such as crystals or icicles, grow by accumulating more of the same material of which they are made. In contrast, the growth of living things results from the division and enlargement of cells. Cell division is the formation of two new cells from an existing cell, as shown in Figure 1-3. In unicellular organisms, the primary change that occurs following cell division is cell enlargement. In multi- cellular life, however, organisms mature through cell division, cell enlargement, and development. Development is the process by which an organism becomes a mature adult. Development involves cell division and cell differen- tiation, or specialization. As a result of development, an adult organism is composed of many cells specialized for different func- tions, such as carrying oxygen in the blood or hearing. In fact, the human body is composed of trillions of specialized cells, all of which originated from a single cell, the fertilized egg. This unicellular organism, Escherichia coli, inhabits the human intestines. E. coli reproduces by means of cell division, during which the original cell splits into two identical offspring cells. FIGURE 1-3 Observing Homeostasis Materials 500 mL beakers (3), wax pen, tap water, thermometer, ice, hot water, goldfish, small dip net, watch or clock with a second hand Procedure 1. Use a wax pen to label three 500 mL beakers as follows: 27°C (80°F), 20°C (68°F), 10°C (50°F). Put 250 mL of tap water in each beaker. Use hot water or ice to adjust the tem- perature of the water in each beaker to match the temperature on the label. 2. Put the goldfish in the beaker of 27°C water. Record the number of times the gills move in 1 minute. 3. Move the goldfish to the beaker of 20°C water. Repeat observations. Move the goldfish to the beaker of 10°C. Repeat observations. Analysis What happens to the rate at which gills move when the temp- erature changes? Why? How do gills help fish maintain homeostasis? Quick Lab mb06se_bios01.qxd 5/18/07 10:37 AM Page 8 THE SCIENCE OF LIFE 9 Reproduction All organisms produce new organisms like themselves in a process called reproduction. Reproduction, unlike other characteristics, is not essential to the survival of an individual organism. However, because no organism lives forever, reproduction is essential for the continuation of a species. Glass frogs, as shown in Figure 1-4, lay many eggs in their lifetime. However, only a few of the frogsâ off- spring reach adulthood and successfully reproduce. During reproduction, organisms transmit hereditary informa- tion to their offspring. Hereditary information is encoded in a large molecule called deoxyribonucleic acid, or DNA. A short segment of DNA that contains the instructions for a single trait of an organism is called a gene. DNA is like a large library. It contains all the booksâgenesâthat the cell will ever need for making all the struc- tures and chemicals necessary for life. Hereditary information is transferred to offspring during two kinds of reproduction. In sexual reproduction, hereditary information recombines from two organisms of the same species. The resulting offspring are similar but not identical to their parents. For example, a male frogâs sperm can fertilize a femaleâs egg and form a single fer- tilized egg cell. The fertilized egg then develops into a new frog. In asexual reproduction, hereditary information from different organisms is not combined; thus the original organism and the new organism are genetically the same. A bacterium, for example, reproduces asexually when it splits into two identical cells. Change Through Time Although individual organisms experience many changes during their lifetime, their basic genetic characteristics do not change. However, populations of living organisms evolve or change through time. The ability of populations of organisms to change over time is important for survival in a changing world. This factor is also impor- tant in explaining the diversity of life-forms we see on Earth today. 1. How does biology affect a personâs daily life? 2. How does biology affect society? 3. Name the characteristics shared by living things. 4. Summarize the hierarchy of organization found in complex multicellular organisms. 5. What are the different functions of homeostasis and metabolism in living organisms? 6. How does the growth among living and nonliv- ing things differ? 7. Why is reproduction an important characteristic of life? CRITICAL THINKING 8. Applying Information Crystals of salt grow and are highly organized. Why donât biologists con- sider them to be alive? 9. Analyzing Models When a scientist designs a space probe to detect life on a distant planet, what kinds of things should it measure? 10. Making Comparisons Both cells and organisms share the characteristics of life. How are cells and organismsood supply will be like in the near future.EVOLUTION OF LIFE Individual organisms change during their lifetime, but their basic genetic characteristics do not change. However, populations of liv- ing organisms do change through time, or evolve. Evolution, or descent with modification, is the process in which the inherited characteristics within populations change over generations, such that genetically distinct populations and new species can develop. Evolution as a theme in biology helps us understand how the various branches of the âtree of lifeâ came into existence and have changed over time. It also explains how organisms alive today are related to those that lived in the past. Finally, it helps us understand the mechanisms that underlie the way organisms look and behave. Natural Selection The ability of populations of organisms to change over time is important for survival in a changing world. According to the theory of evolution by natural selection, organisms that have certain favorable traits are better able to survive and reproduce success- fully than organisms that lack these traits. One product of natural selection is the adaptation of organisms to their environment. Adaptations are traits that improve an indi- vidualâs ability to survive and reproduce. For example, rabbits with white fur and short ears in a snowy place, such as the one in Figure 1-7a, may avoid predators and frostbitten ears more often than those with dark fur and long ears. Thus, the next generation of rabbits will have a greater percentage of animals carrying the genes for white fur and short ears. In contrast, the brown, long- eared rabbit, as shown in Figure 1-7b, would survive and reproduce more successfully in a hot desert environment. The survival and reproductive success of organisms with favor- able traits cause a change in populations of organisms over gener- ations. This descent with modification is an important factor in explaining the diversity of organisms we see on Earth today. 1. Name three unifying themes found in biology. 2. How is the unity and diversity in the living world represented? 3. Identify the three domains and the kingdoms found in each domain. 4. How are organisms interdependent? 5. Describe why evolution is important in explain- ing the diversity of life. 6. Distinguish between evolution and natural selection. CRITICAL THINKING 7. Applying Information Assign the various top- pings you put on pizza to the appropriate domains and kingdoms of life. 8. Analyzing Graphics According to the âtreeâ in Figure 1-5, which of these pairs are more closely related: Archaea:Bacteria or Archaea:Eukarya? 9. Making Hypotheses Fossil evidence shows that bats descended from shrewlike organisms that could not fly. Write a hypothesis for how natural selection might have led to flying bats. SECTION 2 REVIEW (a) This short-eared arctic hare, Lepus arcticus, is hidden from predators and protected from frostbite in a snowy environment. (b) The mottled brown coats of desert rabbits blend in with the dirt and dry grasses, and their long ears help them radiate excess heat and thus avoid overheating. FIGURE 1-7 (a) (b) Copyright © by Holt, Rinehart and Winston. All rights reserved. THE SCIENCE OF LIFE 13 TH E STUDY OF BIOLOGY Curiosity leads us to ask questions about life. Science provides a way of answering such questions about the natural world. Science is a systematic method that involves forming and testing hypotheses. More importantly, science relies on evidence, not beliefs, for drawing conclusions. SCIENCE AS A PROCESS Science is characterized by an organized approach, called the scientific method, to learn how the natural world works. The methods of science are based on two important principles. The first principle is that events in the natural world have natural causes. For example, the ancient Greeks believed that lightning and thunder occurred because a supernatural god Zeus hurled thunderbolts from the heavens. By contrast, a scientist considers lightning and thunder to result from electric charges in the atmos- phere. When trying to solve a puzzle from nature, all scientists, such as the one in Figure 1-8, accept that there is a natural cause to solve that puzzle. A second principle of science is uniformity. Uniformity is the idea that the fundamental laws of nature operate the same way at all places and at all times. For example, scientists assume that the law of gravity works the same way on Mars as it does on Earth. Steps of the Scientific Method Although there is no single method for doing science, scientific studies involve a series of common steps. 1. The process of science begins with an observation. An observation is the act of perceiving a natural occurrence that causes someone to pose a question. 2. One tries to answer the question by forming hypotheses (singular, hypothesis). A hypothesis is a proposed explanation for the way a particular aspect of the natural world functions. 3. A prediction is a statement that forecasts what would happen in a test situation if the hypothesis were true. A prediction is recorded for each hypothesis. 4. An experiment is used to test a hypothesis and its predictions. 5. Once the experiment has been concluded, the data are analyzed and used to draw conclusions. 6. After the data have been analyzed, the data and conclusions are communicated to scientific peers and to the public. This way oth- ers can verify, reject, or modify the researcherâs conclusions. SECTION 3 OBJECTIVES â Outline the main steps in the scientific method. â Summarize how observations are used to form hypotheses. â List the elements of a controlled experiment. â Describe how scientists use data to draw conclusions. â Compare a scientific hypothesis and a scientific theory. â State how communication in science helps prevent dishonesty and bias. VOCABULARY scientific method observation hypothesis prediction experiment control group experimental group independent variable dependent variable theory peer review All researchers, such as the one releasing an owl above, use the scientific method to answer the questions they have about nature. FIGURE 1-8 Copyright © by Holt, Rinehart and Winston. All rights reserved. 14 CHAPTER 1 OBSERVING AND ASKING QUESTIONS The scientific method generally begins with an unexplained observa- tion about nature. For example, people have noticed for thousands of years that owls can catch prey in near total darkness. As shown in steps and of Figure 1-9, an observation may then raise ques- tions. The owl observation raises the question: How does an owl detect prey in the dark? FORMING A HYPOTHESIS After stating a question, a biologist lists possible answers to a sci- entific questionâhypotheses. Good hypotheses answer a question and are testable in the natural world. For example, as shown in step Figure 1-9, there are several possible hypotheses for the question of how owls hunt at night: (a) owls hunt by keen vision in the dark; (b) owls hunt by superb hearing; or (c) owls hunt by detecting the preyâs body heat. Predicting To test a hypothesis, scientists make a prediction that logically fol- lows from the hypothesis. A prediction is what is expected to hap- pen if each hypothesis were true. For example, if hypothesis (a) is true, (owls hunt by keen night vision) then one can predict that the owl will pounce only on the mouse in either a light or a dark room. If hypothesis (b) is true (owls hunt by hearing), then one can pre- dict that in a lighted room, the owl will pounce closer to the mouseâs head. But, in a dark room, the owl should pounce closer to a rustling leaf attached to the mouse. Finally, if hypothesis (c) is true (owls hunt by sensing body heat), then an owl would strike only the prey no matter the room conditions, because owls hunt by detecting the preyâs body heat. 3 1 2 Copyright © by Holt, Rinehart and Winston. All rights reserved. A scientific study includes observations, questions, hypotheses, predictions, experiments, data analysis, and conclu- sions. A biologist can use the scientific method to set up an experiment to learn how an owl captures prey at night. FIGURE 1-9 1 OBSERVATION Owls capture prey on dark nights. 2 QUESTION How do owls detect prey on dark nights? 3 HYPOTHESES a) Owls hunt in the dark by vision. b) Owls hunt in the dark by hearing. c) Owls hunt in the dark by sensing body heat. THE SCIENCE OF LIFE 15 Notice that these predictions make it difficult to distinguish be- tween the vision and body heat hypotheses. The reason is that both hypotheses predict that the owl could grab the mouse in a dark room. Also, these three hypotheses do not eliminate all other factors that could influence how the owl finds its prey. However, testing predictions can allow one to begin rejecting hypotheses and thus to get closer to determining the answer(s) to a question. DESIGNING AN EXPERIMENT Biologists often test hypotheses by setting up an experiment. Step in Figure 1-9 outlines an experiment to test the hypotheses about how an owl hunts at night. First, experimenters set up a room with an owl perch high on one side and a small trap door on the other side for releasing mice. Then, they tied a leaf to each mouseâs tail with a string and released each mouse into the room. Next, each mouse ran silently across the room, but the leaf trailed behind, making a rustling noise. During half of the trials, the lights were on. During the other half, the room was dark. Technicians videotaped all the action in the chamber with an infrared light, which owls cannot see. The researchers then viewed the videos and measured the position of the owlâs strike relative to each mouseâs head. Performing the Experiment Many scientists use a controlled experiment to test their hypotheses. A controlled experiment compares an experimental group and a control group and only has one variable. The control group pro- vides a normal standard against which the biologist can compare results of the experimental group. The experimental group is iden- tical to the control group except for one factor, the independent variable. The experimenter manipulates the independent variable, sometimes called the manipulated variable. 4 4 EXPERIMENT 5 DATA COLLECTION AND ANALYSIS Measure and compare the distance from the owlâs strike to the mouse and to the leaf in light and dark. 6 CONCLUSION Data supported the hearing hypothesis: Owls hunt in the dark by hearing. prey Test predictions of the three hypotheses. Control: In the light Experimental: In the dark 1 2 3 4 5 6 7 8 9 10 11 Predicting Results Materials 2 Petri dishes with agar, cellophane tape, wax pen Procedure 1. Open one of the Petri dishes, and streak your finger across the surface of the agar. 2. Replace the lid, and seal it with the tape. Label this Petri dish with your name and a number 1. 3. Seal the second Petri dish with- out removing the lid. Label this Petri dish with your name and the number 2. 4. Write a prediction about what will happen in each dish. Store your dishes as your teacher directs. Record your observations. Follow your teacherâs directions for disposal of your dishes. Analysis Was your prediction accurate? What evidence can you cite to support your prediction? If you did not obtain the results you predicted, would you change your testing method or your prediction? Explain. Evaluate the importance of obtaining a result that does not support your prediction. Quick Lab mb06se_bios03.qxd 5/18/07 10:40 AM Page 15 16 CHAPTER 1 The independent variable in the owl experiment is the presence or absence of light. In the owl experiment, the control group hunts in the light, and the experimental group hunts in the dark. In addi- tion to varying the independent variable, a scientist observes or measures another factor called the dependent variable, or respond- ing variable, because it is affected by the independent variable. In the owl experiment, the dependent variable is distance from the owlâs strike to the mouseâs head. Testing the Experiment Some controlled experiments are conducted âblind.â In other words, the biologist who scores the results is unaware of whether a given subject is part of the experimental or control group. This factor helps eliminate experimenter bias. Experiments should also be repeated, because living systems are variable. Moreover, scien- tists must collect enough data to find meaningful results. COLLECTING AND ANALYZING DATA Most experiments measure a variableâthe dependent variable. This measurement provides quantitative data, data measured in numbers. For example, in the experiment above, scientists mea- sured the distance of an owlâs strike from the preyâs head in cen- timeters, as shown in step of Figure 1-9. An eventâs duration in milliseconds is also an example of quantitative data. Biologists usually score the results of an experiment by using one of their senses. They might see or hear the results of an experiment. Scientists also extend their senses with a micro- scope for tiny objects or a microphone for soft sounds. In the owl experiment, biologists extended their vision with infrared cameras. Analyzing and Comparing Data After collecting data from a field study or an experiment and then organizing it, biologists then analyze the data. In analyzing data, the goal is to determine whether the data are reliable, and whether they support or fail to support the predictions of the hypothesis. To do so, scientists may use statistics to help determine relation- ships between the variables involved. They can then compare their data with other data that were obtained in other similar studies. It is also important at this time to determine possible sources of error in the experiment just per- formed. Scientists usually display their data in tables or graphs when analyzing it. For the owl study, biologists could have made a bar graph such as the one in Figure 1-10, which shows the average distance from the owlâs strike relative to the mouseâs head or the leaf in the light and in the dark. 5 5 0 10 15 20 25 In the light In the dark Average distance from strike (cm) Distance Between Owl Strike and a Mouse or From a Leaf Attached to Mouse 30 Mouse Leaf Mouse Leaf The data below are hypothetical results that might occur from the described owl experiment.The independent variable is the darkness of the room, and the dependent variable is how far the owl struck from the mouseâs head.The data show that the owl strikes more accurately at the mouse in the light but strikes more accurately at the leaf in the dark. FIGURE 1-10 Copyright © by Holt, Rinehart and Winston. All rights reserved. THE SCIENCE OF LIFE 17 DRAWING CONCLUSIONS Biologists analyze their tables, graphs, and charts to draw conclu- sions about whether or not a hypothesis is supported, as shown in step of Figure 1-9. The hypothetical owl data show that in the light, owls struck with greater accuracy at the mouse than at the leaf, but in the dark, owls struck with greater accuracy at the leaf than the mouse. Thus, the findings support the hearing hypothe- sis, but not the vision hypothesis. An experiment can only disprove, not prove, a hypothesis. For example, one cannot conclude from the results that the hearing hypothesis is proven to be true. Perhaps the owl uses an unknown smell to strike at the mouse. One can only reject the vision hypothe- sis because it did not predict the results of the experiment correctly. Acceptance of a hypothesis is always tentative in science. The scientific community revises its understanding of phenomena, based on new data. Having ruled out one hypothesis, a biologist will devise more tests to try to rule out any remaining hypotheses. Making Inferences Scientists often draw inferences from data gathered during a field study or experiment. An inference (IN-fuhr-uhns) is a conclusion made on the basis of facts and previous knowledge rather than on direct observations. Unlike a hypothesis, an inference is not directly testable. In the owl study, it is inferred that the owl detects prey from a distance rather than by direct touch. Applying Results and Building Models As shown in Figure 1-11, scientists often apply their findings to solve practical problems. They also build models to represent or describe things. For example in 1953, James Watson and Francis Crick used cardboard balls and wire bars to build physical models of atoms in an attempt to understand the structure of DNA. Mathematical models are sets of equations that describe how dif- ferent measurable items interact in a system. The experimenter can adjust variables to better model the real-world data. CONSTRUCTING A THEORY When a set of related hypotheses is confirmed to be true many times, and it can explain a great amount of data, scientists often reclassify it as a theory. Some examples include the quantum the- ory, the cell theory, or the theory of evolution. People commonly use the word âtheoryâ in a different way than scientists use the word. People may say âItâs just a theoryâ suggesting that an idea is untested, but scientists view a theory as a highly tested, generally accepted principle that explains a vast number of observations and experimental data. 6 Copyright © by Holt, Rinehart and Winston. All rights reserved. Biologists often apply their knowledge of the natural world to practical problems. Studies on the owlâs keen ability to locate sounds in space despite background noise are helping biotechnologists and bioengineers develop better solutions for people with impaired hearing, such as the people shown in this picture. FIGURE 1-11 18 CHAPTER 1 COMMUNICATING IDEAS An essential aspect of scientific research is scientists working together. Scientists often work together in research teams or sim- ply share research results with other scientists. This is done by publishing findings in scientific journals or presenting them at sci- entific meetings, as shown in Figure 1-12. Sharing information allows others working independently to verify findings or to con- tinue work on established results. For example, Roger Payne pub- lished the results of his owl experiments in a journal in 1971. Then, other biologists could repeat it for verification or use it to study the mechanisms introduced by the paper. With the growing impor- tance of science in solving societal issues, it is becoming increas- ingly vital for scientists to be able to communicate with the public at large. Publishing a Paper Scientists submit research papers to scientific journals for publica- tion. A typical research paper has four sections. First, the Introduction poses the problem and hypotheses to be investigated. Next, the Materials and Methods describe how researchers proceeded with the experiment. Third, the Results state the findings the experiment presented, and finally, the Discussion gives the significance of the experiment and future directions the scientists will take. Job Description Forensic biolo- gists are scientists who study biological materials to investigate potential crimes and other legal issues against humans and animals. Forensic scientists have knowledge in areas of biology, such as DNA and blood pattern analysis, and work in private sector and public laboratories. Focus On a Forensic Biologist As a law enforcement forensic specialist for the Texas Parks and Wildlife Department, Beverly Villarreal assists the game warden in investigations of fish and wildlife violations, such as illegal hunting and fishing. Villarreal analyzes blood and tissue samples to identify species of animals such as fish, birds, and reptiles. Her work helps game wardens as they enforce state laws regarding hunting and fishing. Most people think of forensic scientists as the glamorous crime investigators on TV, but according to Villarreal real forensic scientists âspend a great deal of time at a lab bench running analysis after analysis.â Many of the methods used in animal forensics, such as DNA sequenc- ing, are also used in human forensics. Education and Skills âą High schoolâthree years of science courses and four years of math courses. âą Collegeâbachelor of science in biol- ogy, including course work in zoology and genetics, plus experience in per- forming DNA analyses. âą Skillsâpatience, attention to detail, and ability to use fine tools. Careers in BIOLOGY Forensic Biologist For more about careers, visit go.hrw.com and type in the keyword HM6 Careers. www.scilinks.org Topic: Scientific Investigations Keyword: HM61358 mb06se_bios03.qxd 5/18/07 10:40 AM Page 18 THE SCIENCE OF LIFE 19 1. What two principles make the scientific method a unique process? 2. Define the roles of observations and hypotheses in science. 3. Summarize the parts of a controlled experiment. 4. Summarize how we make conclusions about the results of an experiment. 5. Why is the phrase, âitâs just a theoryâ misleading? 6. Give another example of a conflict of interest. CRITICAL THINKING 7. Making Hypotheses On a nocturnal owlâs skull, one ear points up, and the other ear points down. Suggest a hypothesis for this observation. 8. Designing Experiments Design an experiment to establish if owls hunt by keen sight or hunt by heat seeking. 9. Calculating Information What was the average distance between the owlâs strike and the mouse if the recorded differences in this experiment were 25, 22, 19, 19, and 15? SECTION 3 REVIEW After scientists submit their papers to a scientific journal, the editors of that journal will send the paper out for peer review. In a peer review, scientists who are experts in the field anonymously read and critique that research paper. They determine if a paper pro- vides enough information so that the experiment can be duplicated and if the author used good experimental controls and reached an accurate conclusion. They also check if the paper is written clearly enough for broad understanding. Careful analysis of each otherâs research by fellow scientists is essential to making scientific progress and preventing scientific dishonesty. HONESTY AND BIAS The scientific community depends on both honesty and good sci- ence. While designing new studies, experimenters must be very careful to prevent previous ideas and biases from tainting both the experimental process and the conclusions. Scientists have to keep in mind that they are always trying to disprove their favorite ideas. Scientists repeat experiments to verify previous findings. This allows for science to have a method for self-correction and it also keeps researchers honest and credible to their peers in the field. Conflict of Interest For most scientists, maintaining a good reputation for collecting and presenting valid data is more important than temporary prestige or income. So, scientists try to avoid any potential conflicts of interest. For example, a scientist who owns a biotechnology company and manufactures a drug would not be the best researcher to critically test that drugâs safety and effectiveness. To avoid this potential con- flict of interest, the scientist allows an unaffected party, such as a research group, to test the drugâs effectiveness. The threat of a potential scandal based on misleading data or conclusions is a pow- erful force in science that helps keep scientists honest and fair. Scientists present their experiments in various forms. The scientists above are presenting their work in the form of a poster at a scientific meeting. FIGURE 1-12 Copyright © by Holt, Rinehart and Winston. All rights reserved. The Internet can provide a wealth of scientific information for a report, but the information may not always be credible or accurate. You can use the methods above to check the accuracy and credibility of your sources. SCIENCE TECHNOLOGY SOCIETY SCIENCE ON THE INTERNET: A New Information Age I n the past, students research- ing a science topic would typ- ically begin their research by visiting a library to use printed reference materials, such as encyclopedias. Today, most stu- dents research topics by using a computer and searching for information on the Internet. The Internet can provide students with a wealth of infor- mation. But which Web sites have accurate information, and which Web sites do not? Checking Web Addresses Students should use the Web address, or URL, to establish the Web siteâs credibility. Usually, the domain name can suggest who has published the Web site. Web sites can be pub- lished by governmental agen- cies (ends in âdot govâ or .gov), by educational institutions (ends in âdot eduâ or .edu), by organizations (ends in âdot orgâ or .org), or by commercial businesses (ends in âdot comâ or .com). Government Web sites are usually reliable. Examples of credible governmental Web sites are the National Institutes of Health (NIH) and the Food and Drug Administration (FDA). University and medical school sites are also reliable sources of information. Many organiza- tions that research and teach the public about specific diseases and conditions can also provide reliable information. Examples of such organizations are the American Cancer Society and the American Heart Association. Evaluating Web Sites The credibility of the author of the Web site should also be checked. Make sure the author is not trying to sell anything and is established in his or her field. For example, a health Web siteâs author should be a med- ical professional. It is also important to check the date that the information was posted on the Web to ensure that the information is current. Also, the Web site should provide ref- erences from valid sources, such as scientific journals or govern- ment publications. Finally, the student should always double-check informa- tion between several reliable Web sites. If two or three reliable sites provide the same informa- tion, the student can feel confi- dent in using that information. Web Sites for Students The Internet Connect boxes in this textbook have all been reviewed by professionals at the National Science Teachers Association (NSTA). Students can trust that these sites are reliable sources for science- or health-related topics. REVIEW 1. Which types of Web addresses are the most reliable? 2. List four important features to evaluate when using a Web site for research. 3. Supporting Reasoned Opinions Why do you think a Web site that is advertising a product may not offer accurate information? REVIEW 20 www.scilinks.org Topic: Using the Internet Keyword: HM61589 mb06se_biosts.qxd 5/18/07 10:42 AM Page 20 TOOLS AND TECHNIQUES With proper equipment and good methods, biologists can see, manipulate, and understand the natural world in new ways. Microscopes are one of many useful tools used to unlock natureâs biological secrets. MICROSCOPES AS TOOLS Tools are objects used to improve the performance of a task. Microscopes are tools that extend human vision by making enlarged images of objects. Biologists use microscopes to study organisms, cells, cell parts, and molecules. Microscopes reveal details that otherwise might be difficult or impossible to see. Light Microscopes To see small organisms and cells, biologists typically use a light microscope, such as the one shown in Figure 1-13. A compound light microscope is a microscope that shines light through a spec- imen and has two lenses to magnify an image. To use this micro- scope, one first mounts the specimen to be viewed on a glass slide. The specimen must be thin enough for light to pass through it. For tiny pond organisms, such as the single-celled paramecium, light passing through the organism is not a problem. For thick objects, such as plant stems, biologists must cut thin slices for viewing. There are four major parts of a compound light microscope. For further description of the parts of a micro- scope, see the Appendix. 1. Eyepiece The eyepiece (ocular (AHK-yoo-luhr) lens) magnifies the image, usually 10 times. 2. Objective Lens Light passes through the specimen and then through the objective lens, which is located directly above the specimen. The objective lens enlarges the image of the specimen. Scientists sometimes use stains to make the image easier to see. 3. Stage The stage is a platform that supports a slide holding the specimen. The slide is placed over the opening in the stage of the microscope. 4. Light Source The light source is a light bulb that provides light for viewing the image. It can be either light reflected with a mirror or an incandescent light from a small lamp. SECTION 4 OBJECTIVES â List the function of each of the major parts of a compound light microscope. â Compare two kinds of electron microscopes. â Describe the importance of having the SI system of measurement. â State some examples of good laboratory practice. VOCABULARY compound light microscope eyepiece (ocular lens) objective lens stage light source magnification nosepiece resolution scanning electron microscope transmission electron microscope metric system base unit Compound light microscopes open the human eye to an interesting world including tiny pond organisms, healthy and diseased cells, and the functioning of cell parts. FIGURE 1-13 Objective lens Eyepiece (ocular lens) Stage Light THE SCIENCE OF LIFE 21 Copyright © by Holt, Rinehart and Winston. All rights reserved. 22 CHAPTER 1 Magnification and Resolution Microscopes vary in powers of magnification and resolution. Magnification is the increase of an objectâs apparent size. Revolving the nosepiece, the structure that holds the set of objective lens, rotates these lenses into place above the specimen. In a typical com- pound light microscope, the most powerful objective lens produces an image up to 100 times (100) the specimenâs actual size. The degree of enlargement is called the power of magnification of the lens. The standard ocular lens magnifies a specimen 10 times (10). To compute the power of magnification of a microscope, the power of magnification of the strongest objective lens (in this case, 100) is multiplied by the power of magnification of the ocular lens (10). The result is a total power of magnification of 1000. Resolution (REZ-uh-LOO-shuhn) is the power to show details clearly in an image. The physical properties of light limit the ability of light microscopes to resolve images, as shown in Figure 1-14a. At pow- ers of magnification beyond about 2,000, the image of the speci- men becomes fuzzy. For this reason, scientists use other microscopes to view very small cellsNatura Latin B/CWhen Europeans met American Indians in the late 15th century, the people of two continents exchanged many beneficial customs and goods. Europeans received New World crops such as potatoes and corn. American Indians acquired cloth and horses. However, besides the beneficial exchanges, Europeans and American Indians often traded deadly germsâbacteria and virusesâfor which they had no immunity. Smallpox and Indians Image 1: Smallpox epidemics helped Europeans conquer the Aztec and Incan Empires of Mexico and South America. North American Indians quickly concluded that contact with Europeans often resulted in devastating diseases that caused widespread death. This drawing, made in the 1500s in Mexico, shows how the disease was passed from a European to an American Indian through simple contact. Many of the diseases that were common in Europe were entirely new to the peoples of North America. Diseases such as tuberculosis and measles could be fatal, but Europeans had developed resistance to the disease, so many people survived. However, when European diseases infected American Indians with no previous exposure, the people suffered terribly. The most devastating of these diseases was smallpox which is caused by a virus (Variola major). Smallpox, like many other diseases, had a latent period of about one week between the time the person was exposed to the disease and the time when signs of the disease became apparent. During this time, the sick person might begin a journey and carry the germs along with him. Anyone the person met would be exposed to smallpox. Anything the victim touched including clothing, bedding, or unwashed dishes carried living germs of smallpox. Cotton Mather Image 2: Cotton Mather was a Boston minister. When smallpox threatened Boston, he remembered reading about how the Turks inoculated people with dried material from smallpox blisters. The inoculation usually gave the person a mild case of the disease and future immunity. The procedure was highly controversial, but it helped save the lives of 274 people who were inoculated during the Boston smallpox epidemic of 1721. Symptoms of the disease began with fever, chills, and aches. The fever might raise a personâs temperature from the normal 98.6o to a dangerous 106o. After four days of misery, the victim entered the second stage when large pustules (fluid-filled bumps) appeared on the body. The rash made the person feel as if their skin were on fire. After suffering with the rash for nine days, the victim entered a new stage-if he or she had survived this long. The pustules opened and dried up. Each pustule formed a scab that turned into a scar that marked the personâs face for the rest of his or her life. Complications of smallpox for those who survived might include loss of vision or damage to the lungs, heart, or liver. Waterhouse Image 3: Dr. Benjamin Waterhouse of Harvard University brought Jennerâs smallpox preventative to the United States. It was called vaccination and used cowpox as the infective material. This much milder form of pox gave immunity to smallpox with fewer complications. Dr. Waterhouse encouraged President-elect Thomas Jefferson to promote vaccination. Jefferson responded, âEvery friend of humanity must look with pleasure on this discovery, by which one evil more is withdrawn from the condition of man.â (T. Jefferson 12/25/1800 to Benjamin Waterhouse, December 25, 1800) Historians have found evidence of smallpox as far back as 1157 B.C. when the Egyptian pharaoh Ramses V apparently died of smallpox. From Egypt, where scientists believe smallpox began, the disease spread to Asia. Europeans began to experience periodic epidemics of smallpox in the14th century when Crusaders returning from the Middle East brought smallpox to Europe. People who survived the disease were immune and could not get smallpox again. This fact explains why epidemics struck periodically and the disease was not a constant threat to European societies. Smallpox Vaccination 1803 Image 4: Dr. Edward Jennerâs new smallpox vaccination (from cowpox) was widely accepted. This medical image was published by a Spanish physician to teach colonial doctors how to apply the vaccine to native Mexicans. The scratches were supposed to go through several stages of development as evidence that the vaccine had given the patient immunity. Vaccination was very effective in preventing smallpox epidemics among those who received the vaccine. In 1520, while CortĂ©s was trying to conquer the Aztecs, smallpox broke out among the Spaniards and was transferred to the Aztecs. By 1527, the disease had migrated through Central America to Peru where it helped Pizarro conquer the Incas. (See Image 1.) In 1633, smallpox infected American Indians living near the English colony of Plymouth, Massachusetts. The disease traveled very quickly to tribes living far inland from the English colonies. In 1721, a smallpox epidemic threatened the English colonists of Boston. (See Image 2.) Cotton Mather, a Boston minister, wanted to inoculate people against the disease. He knew that Turkish healers took material from a dried smallpox scab and injected it into the body of a healthy person by scratching the surface of the skin. The patients developed a mild form of the disease from which they recovered. The procedure was highly controversial in Boston where about 280 Bostonians accepted inoculation. The epidemic infected more than half of the people living in Boston at the time. About 15% of those who got sick died of the disease. Among those who were inoculated, only six (2%) died of smallpox. The practice of inoculation spread to other English colonies, but not to the American Indian tribes living near the colonies. Late in the 18th century, British doctor Edward Jenner recognized that people who milked cows never came down with smallpox. They had already been infected with cowpox, a similar, but much milder disease that gave them immunity to smallpox. In 1796, Jenner inoculated a young man with cowpox virus he had collected from a milkmaid. The young man had a mild infection for less than 24 hours and recovered. Jennerâs efforts resulted in a widespread acceptance of vaccination (vaccine comes from Latin words meaning âtaken from a cowâ). By 1800, many Americans were receiving smallpox vaccinations. (See Image 3.) President Thomas Jefferson supported and encouraged the vaccination program in major American cities. (See Image 4.) By the middle of the 19th century, smallpox was under control, but broke out from time to time among unvaccinated people. Bismarck, Dakota Territory, experienced a small outbreak of smallpox in 1882. American Indians, however, were still subject to the disease in its most dangerous form.Buatkan pertanyaan dari materi ini: MATERI PELAJARAN PERTEMUAN KELIMA 1. Pengertian resensi Kata resensi berasal dari bahasa Latin recensere atau recensio yang berarti meninjau kembali atau melihat kembali. Dalam konteks karya sastra, resensi adalah kegiatan memberikan tanggapan, penilaian, serta ulasan terhadap suatu karya, baik karya fiksi maupun nonfiksi. Jadi, resensi cerpen adalah kegiatan menilai, mengulas, dan memberikan pendapat terhadap sebuah cerpen dengan tujuan untuk mengetahui kelebihan, kekurangan, dan nilai yang terkandung di dalamnya. Melalui resensi, seseorang tidak hanya menceritakan ulang isi cerpen, tetapi juga menyampaikan pandangan kritis terhadap isi, gaya bahasa, alur, tokoh, dan pesan yang ingin disampaikan pengarang.\ 2. Tujuan Resensi Resensi memiliki beberapa tujuan penting, baik bagi pembaca, penulis, maupun dunia sastra. Berikut tujuan resensi cerpen secara umum: a. Memberikan penilaian dan ulasan tentang isi, struktur, dan kualitas suatu cerpen, terutama dalam hal tema, alur, tokoh, dan pesan moral. b. Memberikan informasi tentang keunggulan dan kelemahan sebuah cerpen serta memberikan rekomendasi apakah cerpen tersebut menarik untuk dibaca. c. Membantu pembaca memahami isi cerpen tanpa harus membacanya secara lengkap, dengan memberikan pandangan yang objektif mengenai isi dan kualitas karya tersebut. d. Membantu penulis cerpen memperoleh masukan atau saran agar dapat memperbaiki karya mereka di masa mendatang. e. Memberikan pemahaman yang menyeluruh (komprehensif) tentang hal-hal yang tampak maupun tersirat dalam cerpen, seperti nilai-nilai kehidupan dan pesan sosial. f. Mengajak pembaca berpikir dan merenung, serta mendiskusikan lebih dalam fenomena atau problematika yang diangkat dalam cerpen. g. Memberikan pertimbangan kepada pembaca mengenai isi, pesan, dan kualitas cerpen sebelum mereka memutuskan untuk membaca atau menilainya sendiri. 3. Fungsi Resensi Cerpen Resensi tidak hanya berfungsi bagi pembaca, tetapi juga memiliki manfaat luas bagi penulis, penerbit, dan media massa. a. Bagi Penulis Cerpen âą Resensi menjadi umpan balik (feedback) dan sarana evaluasi terhadap karya yang ditulis. âą Penulis dapat mengetahui pendapat dan tanggapan pembaca terhadap cerpen yang dibuatnya. âą Resensi membantu penulis meningkatkan kualitas karya pada penulisan berikutnya. b. Bagi Penerbit âą Resensi berfungsi sebagai alat promosi untuk memperkenalkan karya sastra yang diterbitkan kepada masyarakat. âą Penerbit dapat melihat tanggapan atau sambutan pembaca terhadap cerpen yang dipublikasikan. âą Melalui resensi, penerbit dapat memperoleh masukan untuk meningkatkan kualitas penerbitan karya berikutnya. c. Bagi Pembaca atau Penerbit Media Massa âą Resensi menjadi sumber informasi bagi pembaca untuk menilai apakah cerpen tersebut menarik, layak dibaca, atau sesuai dengan minat mereka. âą Media massa menggunakan resensi sebagai ruang literasi publik, tempat pembaca dapat mengenal lebih banyak karya sastra dan memperluas wawasan mereka. âą Resensi juga berfungsi untuk menguji atau mengembangkan topik-topik sosial dan kemanusiaan yang sering diangkat dalam cerpen.CaractĂ©ristiques gĂ©nĂ©rales de la synthĂšse de documents La synthĂšse est un exercice assez simple, car trĂšs technique. Pour rĂ©ussir, il faut nĂ©anmoins faire preuve de rigueur car elle est trĂšs codifiĂ©e. Les piĂšges de la synthĂšse La plupart des Ă©tudiants ignorent la technique de synthĂšse telle quâelle est attendue en BTS. Aussi plusieurs piĂšges sont Ă Ă©viter. La synthĂšse nâest pas une dissertation personnelle Premier Ă©cueil : si lâon se souvint de la consigne vue plus avant, le travail demandĂ© doit ĂȘtre objectif. Aucun point de vue personnel ou mĂȘme apprĂ©ciation subjectif sur les documents ne doit apparaĂźtre dans la rĂ©daction. On recommande dâailleurs aux Ă©tudiants de ne pas utiliser le pronom « je » dans leur travail de façon Ă Ă©viter tout malentendu. Le candidat doit donc rapporter les idĂ©es des auteurs de façon neutre, sans jugement de valeur. La synthĂšse nâest pas un rĂ©sumĂ© des documents La plus grande erreur commise en premiĂšre annĂ©e de BTS consiste Ă rĂ©sumer les documents, les uns aprĂšs les autres. Un petit dĂ©tour par lâĂ©tymologie nous permettra de mieux comprendre le travail attendu. Le terme « synthĂšse » vient du grec sunthesis qui signifie « mise en commun ». Il sâagit donc de rassembler les informations collectĂ©es dans les diffĂ©rents documents en un ensemble organisĂ©, donc cohĂ©rent. Les idĂ©es doivent ĂȘtre confrontĂ©es en Ă©tablissant des liens entre les documents. La synthĂšse nâest pas un montage de citations Le Bac de français est derriĂšre vous. Oubliez (en partie) cette Ă©preuve. Ici, pas de citations, de numĂ©ros de lignes pour appuyer votre rĂ©daction. Votre travail consiste Ă reformuler de façon synthĂ©tique le contenu et les enjeux des documents. La nature du travail demandĂ© Une consigne codifiĂ©e pour rĂ©diger votre synthĂšse Trois adjectifs dans cette consigne. Tout dâabord, la synthĂšse doit ĂȘtre concise, câest-Ă -dire courte et dense. Quatre pages maximum sont gĂ©nĂ©ralement attendues Ă lâĂ©preuve. Nous lâavons dĂ©jĂ Ă©voquĂ© plus haut, la synthĂšse est un exercice absolument objectif. Aucune idĂ©e extĂ©rieure aux documents ni commentaire personnel ne doivent figurer dans la rĂ©daction. Enfin, la synthĂšse est un travail ordonnĂ©. Un plan soutient donc la rĂ©daction, on attend ainsi : âą une introduction; âą un dĂ©veloppement; âą une conclusion. La dĂ©marche Ă adopter pour votre synthĂšse La prĂ©paration de la synthĂšse se dĂ©compose en deux temps : âą Un premier temps consacrĂ© Ă la lecture active de chaque document. Les idĂ©es importantes sont relevĂ©es, les arguments sont listĂ©s, le raisonnement de lâauteur est analysĂ©. âą Un second temps consacrĂ© Ă la mise en relation des diffĂ©rents documents de façon Ă Ă©tablir des liens entre eux : il sâagit en fait de recomposer un dĂ©bat entre les auteurs. Sont-ils dâaccord ? Sâopposent-ils ? Si oui sur quels point ? ⊠La synthĂšse : un acte de communication On veut donc vĂ©rifier que vous savez « lire » : câest-Ă -dire que vous ĂȘtes capable de comprendre ce qui est Ă©crit dans les documents et de reformuler selon des contraintes de longueur de texte. LâĂ©tymologie du verbe « lire » nous le confirme : legere, en latin, signifique « choisir » La mĂ©thodologie de synthĂšse en 10 points Voici un rĂ©capitulatif des 10 maladresses principales Ă Ă©viter et des 10 rĂšgles Ă adopter Les interdits de la synthĂšse 1. Faire des citations des auteurs des documents pour soutenir les idĂ©es avancĂ©es. 2. Donner son avis, Ă©mettre des remarques subjectives : ex : lâauteur oublie malheureusement que⊠3. Faire des rĂ©fĂ©rences Ă des documents hors corpus, faire allusion Ă une autre Ćuvre de lâauteur. 4. RĂ©diger un « catalogue » des idĂ©es sans lien logique entre elles. RĂ©diger au fil de son inspiration. 5. RĂ©diger une synthĂšse longue et dĂ©taillĂ©e. 6. Laisser de cĂŽtĂ© un document, parce que lâon ne lâa pas compris ou quâil nous semble inintĂ©ressant⊠7. Utiliser le pronom « je ». 8. Faire un plan apparent (A, BâŠ) avec des titres. 9. Juxtaposer des rĂ©sumĂ©s des documents. 10. Faire rĂ©fĂ©rence aux documents par le numĂ©ro attribuĂ© dans le dossier. Ce quâil faut faire 1. Reformuler les idĂ©es. 2. Rester neutre, objectif. 3. Ne traiter que les documents proposĂ©s. 4. Traiter les idĂ©es selon un plan prĂ©cis. 5. Quatre pages maximum 6. Traiter tous les documents, mĂȘme de façon inĂ©gale, certains documents sont plus « riches » en idĂ©es que dâautres. 7. PrĂ©fĂ©rer le « on » ou le « nous ». 8. RĂ©diger sans titres avec des phrases de transition. 9. Confronter les idĂ©es communes aux documents. 10. Faire rĂ©fĂ©rence aux documents par le nom de lâauteur et lâinitiale du prĂ©nom. Si ces 10 rĂšgles sont respectĂ©es, une importante partie de la mĂ©thode est acquise ! L'Ă©valuation du travail de synthĂšse On se rappelle que cette Ă©preuve est notĂ©e sur 40 points. En rĂšgle gĂ©nĂ©rale, les correcteurs adoptent le barĂšme suivant qui vise Ă valider 4 grandes compĂ©tences, chacune notĂ©e sur 40 points. Comprendre les documents Ces 10 premiers points valident vos compĂ©tences de lecture : Les idĂ©es essentielles ont-elles Ă©tĂ© bien relevĂ©es ? Tous les documents ont-ils Ă©tĂ© bien compris ? LâunitĂ© thĂ©matique des documents doit apparaĂźtre ans le traitement des informations collectĂ©es. Confronter Le correcteur vĂ©rifiera notamment que tous les documents ont bien Ă©tĂ© exploitĂ©s, quâaucune « impasse » nâa Ă©tĂ© faite. Il sanctionnera, le cas Ă©chĂ©ant, lâajout dâidĂ©es extĂ©rieures. Certains Ă©tudiants pensent que lâintroduction dâidĂ©es extĂ©rieures vient enrichir leur travail et montre leur connaissance du sujet. Il faudra attendre lâĂ©preuve dâĂ©criture personnelle pour le faire. Ici, rappelons-le, seuls les documents proposĂ©s Ă lâĂ©tude figurent dans la synthĂšse. La confrontation des idĂ©es sera Ă©galement Ă©valuĂ©e : Le candidat a-t-il Ă©tabli des liens entre les idĂ©es des auteurs ? Chaque partie de la rĂ©daction repose-t-elle sur plusieurs documents ? Structurer Quelle que soit la logique suivie, la synthĂšse suit un plan. Introduction et conclusion doivent apparaĂźtre clairement. La rĂ©daction suit une ligne directrice et un parcours. Les documents sont rĂ©fĂ©rencĂ©s, lâensemble est organisĂ©. Utilisez des connecteurs logiques pour lier les parties entre elles. Ils faciliteront grandement la lecture et la progression de vos idĂ©es sera plus claire. RĂ©diger & reformuler Une expression Ă©crire claire est attendue. Elle respecte les normes et usages de la langue Ă©crite courante. La richesse du vocabulaire sera valorisĂ©e. Le tout est rĂ©digĂ© : pas de tirets, de titres ou de tissage de citations. Les propos des auteurs sont reformulĂ©s, on sanctionnera ici toute formulation dâapprĂ©ciations personnelles.MATERI PERKULIAHAN Sub-CPMK 1.7 Mampu menghitung performa produksi (IP, FCR) dan melakukan Analisis Usaha Broiler per satu siklus produksi 1. IDENTITAS MATERI Mata Kuliah : Produksi Ternak Potong Unggas Komersil Pokok Bahasan : Evaluasi Performa Produksi dan Analisis Usaha Broiler Sub-CPMK : 1.7 Capaian Pembelajaran : Mahasiswa mampu: Menjelaskan parameter performa produksi broiler. Menghitung Feed Conversion Ratio (FCR). Menghitung Indeks Performa (IP). Menganalisis hasil performa produksi dalam satu siklus pemeliharaan. Menyusun analisis usaha broiler per satu siklus produksi. Menarik kesimpulan kelayakan usaha berdasarkan hasil teknis dan ekonomis. ________________________________________ 2. TUJUAN PEMBELAJARAN Setelah mengikuti perkuliahan ini, mahasiswa diharapkan mampu: Memahami konsep dasar evaluasi performa broiler. Mengidentifikasi data teknis yang dibutuhkan dalam perhitungan performa. Menghitung mortalitas, deplesi, bobot badan rata-rata, FCR, dan IP. Menghitung biaya produksi, penerimaan, keuntungan, dan efisiensi usaha broiler. Menganalisis hubungan antara performa teknis dengan hasil ekonomi usaha. ________________________________________ 3. DESKRIPSI MATERI Dalam usaha broiler modern, keberhasilan produksi tidak hanya diukur dari bobot panen, tetapi juga dari efisiensi penggunaan pakan, tingkat kematian, umur panen, serta keuntungan yang diperoleh per siklus. Oleh karena itu, diperlukan kemampuan untuk menghitung parameter teknis produksi seperti FCR dan IP, serta mengaitkannya dengan analisis usaha agar dapat diketahui apakah usaha berjalan efisien dan menguntungkan. ________________________________________ 4. POKOK-POKOK MATERI A. Konsep Dasar Evaluasi Performa Produksi Broiler 1. Pengertian Performa Produksi Performa produksi broiler adalah gambaran tingkat keberhasilan pemeliharaan ayam broiler selama satu periode/siklus pemeliharaan yang dinilai dari indikator teknis tertentu. 2. Parameter Utama Performa Produksi Parameter yang umum digunakan meliputi: Populasi awal DOC Jumlah ayam hidup saat panen Mortalitas (%) Deplesi (%) Umur panen (hari) Bobot badan rata-rata panen (kg/ekor) Total konsumsi pakan (kg) Feed Conversion Ratio (FCR) Indeks Performa (IP) ________________________________________ B. Parameter Teknis dan Rumus Perhitungan ________________________________________ 1. Mortalitas (%) Pengertian: Persentase ayam yang mati selama masa pemeliharaan. Rumus: "Mortalitas (%)"="Jumlah ayam mati" /"Populasi awal" Ă100 Contoh: Populasi awal = 5.000 ekor Ayam mati = 150 ekor "Mortalitas"=150/5000Ă100=3% ________________________________________ 2. Deplesi (%) Pengertian: Persentase pengurangan populasi akibat kematian dan afkir/culling. Rumus: "Deplesi (%)"="Ayam mati + ayam afkir" /"Populasi awal" Ă100 Jika tidak ada afkir, maka deplesi = mortalitas. ________________________________________ 3. Persentase Ayam Hidup / Livability (%) Rumus: "Livability (%)"="Jumlah ayam panen" /"Populasi awal" Ă100 atau "Livability (%)"=100-"Deplesi (%)" ________________________________________ 4. Bobot Badan Rata-Rata Panen Rumus: "Bobot rata-rata (kg/ekor)"="Total bobot panen (kg)" /"Jumlah ayam panen (ekor)" ________________________________________ 5. Feed Conversion Ratio (FCR) Pengertian: FCR adalah rasio jumlah pakan yang dikonsumsi terhadap pertambahan bobot hidup atau bobot hidup yang dihasilkan. Rumus praktis broiler: "FCR"="Total konsumsi pakan (kg)" /"Total bobot hidup panen (kg)" Interpretasi: Semakin rendah nilai FCR, semakin efisien penggunaan pakan. Contoh: Total pakan = 16.000 kg Total bobot panen = 9.600 kg "FCR"=16.000/9.600=1,67 Interpretasi: Untuk menghasilkan 1 kg bobot hidup, dibutuhkan 1,67 kg pakan. ________________________________________ 6. Indeks Performa (IP) Pengertian: IP adalah indikator gabungan untuk menilai performa pemeliharaan broiler berdasarkan: daya hidup, bobot badan, umur panen, efisiensi pakan. Rumus umum IP: "IP"=("Livability (%)" Ă"Bobot rata-rata (kg)" )/("Umur panen (hari)" Ă"FCR" )Ă100 Contoh: Livability = 97% Bobot rata-rata = 2,0 kg Umur panen = 35 hari FCR = 1,67 "IP"=(97Ă2,0)/(35Ă1,67)Ă100 "IP"=194/58,45Ă100=331,9 Jadi, IP = 331,9 ________________________________________ C. Interpretasi Nilai FCR dan IP 1. Interpretasi FCR < 1,50 = sangat efisien 1,50 â 1,65 = efisien/baik 1,66 â 1,80 = cukup > 1,80 = kurang efisien Catatan: Nilai ini dapat berbeda tergantung strain, umur panen, sistem kandang, musim, dan standar perusahaan. ________________________________________ 2. Interpretasi IP (umum) > 400 = sangat baik / Ù
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ŰȘۧŰČ 351 â 400 = baik 301 â 350 = cukup baik 251 â 300 = sedang < 250 = kurang Dalam praktik kemitraan, IP sering menjadi dasar evaluasi bonus performa. ________________________________________ 5. HUBUNGAN PARAMETER TEKNIS DENGAN KINERJA USAHA Performa teknis sangat menentukan keuntungan usaha broiler: FCR naik â biaya pakan meningkat â laba turun Mortalitas naik â ayam panen berkurang â penerimaan turun Bobot panen rendah â total kg jual turun â omzet turun Umur panen terlalu lama â biaya operasional naik â efisiensi turun IP tinggi â menunjukkan usaha lebih efisien dan berpotensi lebih menguntungkan ________________________________________ 6. ANALISIS USAHA BROILER PER SATU SIKLUS PRODUKSI A. Pengertian Analisis Usaha Analisis usaha broiler adalah perhitungan ekonomi untuk mengetahui: total biaya produksi, total penerimaan, pendapatan/keuntungan, efisiensi usaha, kelayakan usaha per satu siklus pemeliharaan. ________________________________________ B. Komponen Biaya Produksi 1. Biaya Tetap (Fixed Cost) Biaya yang relatif tidak berubah dalam satu siklus, misalnya: Penyusutan kandang Penyusutan peralatan Pajak/sewa lahan (jika dihitung) Bunga modal tetap (opsional) 2. Biaya Variabel (Variable Cost) Biaya yang berubah sesuai jumlah populasi, misalnya: DOC Pakan Obat, vitamin, vaksin (OVK) Sekam/litter Gas/LPG/bahan bakar brooder Listrik dan air Tenaga kerja Desinfektan dan sanitasi Biaya panen/angkut Biaya lain-lain operasional Catatan penting: Pada usaha broiler, pakan biasanya menyumbang 60â70% dari total biaya produksi. ________________________________________ 7. RUMUS ANALISIS USAHA 1. Total Biaya Produksi (TC) "TC"="Biaya Tetap"+"Biaya Variabel" ________________________________________ 2. Total Penerimaan (TR) Jika dijual berdasarkan bobot hidup: "TR"="Total bobot panen (kg)"Ă"Harga jual per kg" Jika ada penerimaan tambahan: "TR total"="Penjualan ayam"+"Penjualan kotoran"+"Penjualan karung pakan/bekas" ________________________________________ 3. Keuntungan / Pendapatan (Ï) Ï="TR"-"TC" ________________________________________ 4. R/C Ratio R/C="TR" /"TC" Kriteria: R/C > 1 â usaha menguntungkan R/C = 1 â impas R/C < 1 â usaha merugi ________________________________________ 5. B/C Ratio (opsional) B/C=("TR" -"TC" )/"TC" ________________________________________ 6. Harga Pokok Produksi (HPP) "HPP per kg"="Total biaya produksi" /"Total bobot panen (kg)" Interpretasi: Jika harga jual > HPP â usaha berpotensi untung. FAKTOR-FAKTOR YANG MEMPENGARUHI FCR, IP, DAN KEUNTUNGAN A. Faktor Teknis Kualitas DOC Mutu pakan Program brooding Kepadatan kandang Ventilasi dan suhu kandang Kualitas air minum Program vaksinasi dan biosekuriti Manajemen litter Ketepatan waktu panen B. Faktor Ekonomi Harga DOC Harga pakan Harga jual ayam hidup Biaya tenaga kerja Biaya energi (gas/listrik) Sistem usaha (mandiri vs kemitraan) STRATEGI MENINGKATKAN PERFORMA DAN KEUNTUNGAN Gunakan DOC berkualitas dan seragam Laksanakan brooding secara optimal (0â14 hari sangat krusial) Pastikan feed intake dan water intake normal Terapkan biosekuriti ketat Kurangi feed wastage Pantau bobot badan mingguan Lakukan culling selektif Tentukan umur panen berdasarkan kombinasi FCR, bobot, dan harga pasar Evaluasi performa tiap siklus dengan pencatatan lengkap Gunakan data historis untuk perbaikan keputusan produksi RANGKUMAN MATERI FCR menunjukkan efisiensi penggunaan pakan. Semakin kecil FCR, semakin baik. IP adalah indikator gabungan performa broiler yang mempertimbangkan: daya hidup, bobot panen, umur panen, efisiensi pakan. Analisis usaha broiler harus mengintegrasikan: aspek teknis (FCR, IP, mortalitas, bobot panen) aspek ekonomi (biaya, penerimaan, laba, R/C, HPP) Usaha broiler dinilai baik apabila: FCR efisien, mortalitas rendah, IP tinggi, HPP lebih rendah dari harga jual, R/C ratio > 1. PENUTUP Kemampuan menghitung FCR, IP, dan melakukan analisis usaha broiler per satu siklus produksi merupakan kompetensi penting dalam manajemen produksi broiler modern. Mahasiswa tidak hanya dituntut memahami teori, tetapi juga harus mampu membaca data produksi, melakukan perhitungan secara akurat, dan mengambil keputusan manajerial berbasis hasil analisis teknis-ekonomis. REFERENSI SINGKAT (untuk bahan ajar/RPS) North, M.O., & Bell, D.D. Commercial Chicken Production Manual. Leeson, S., & Summers, J.D. Commercial Poultry Nutrition. Bell, D.D., & Weaver, W.D. Commercial Chicken Meat and Egg Production. Saputra, dkk. Literatur manajemen broiler modern dan analisis usaha ternak unggas. Standar teknis perusahaan integrator/kemitraan broiler (CP, Japfa, Malindo, dll.) untuk benchmarking FCR dan IP. Crea un quiz con le seguenti domande. Inserisci anche la spiegazione. Domande Vero/Falso: 1. Vero o Falso: Se moltiplichiamo entrambi i membri di una disequazione per un numero negativo, il segno dell'ineguaglianza cambia. o Risposta: Vero o Spiegazione: Quando moltiplichiamo o dividiamo entrambi i membri di una disequazione per un numero negativo, il segno dell'ineguaglianza si inverte. 2. Vero o Falso: Una disequazione puĂČ avere solo una soluzione. o Risposta: Falso o Spiegazione: Una disequazione puĂČ avere zero, una o infinite soluzioni, a seconda dei valori coinvolti. 3. Vero o Falso: Se sommiamo o sottraiamo la stessa quantitĂ da entrambi i membri di una disequazione, la soluzione rimane invariata. o Risposta: Vero o Spiegazione: Aggiungere o sottrarre la stessa quantitĂ da entrambi i membri di una disequazione non cambia la relazione tra le soluzioni. 4. Vero o Falso: Se abbiamo una disequazione del tipo 2x>102x>10, la soluzione Ăš x<5x<5. o Risposta: Vero o Spiegazione: Dividendo entrambi i membri per 22, otteniamo x>5/2x>5/2, che puĂČ essere semplificato a x>2.5x>2.5 o x>5/2x>5/2. 5. Vero o Falso: Una disequazione puĂČ avere solo numeri interi come soluzioni. o Risposta: Falso o Spiegazione: Le soluzioni di una disequazione possono essere numeri razionali o reali, non solo numeri interi. 6. Vero o Falso: Una disequazione del tipo 3xâ2<53xâ2<5 ha x>7/3x>7/3 come soluzione. o Risposta: Falso o Spiegazione: La soluzione corretta Ăš x<7/3x<7/3 poichĂ© 3xâ23xâ2 deve essere minore di 55, non maggiore. 7. Vero o Falso: Una disequazione del tipo 4x+7â„3x+54x+7â„3x+5 ha una soluzione unica. o Risposta: Vero o Spiegazione: Sottraendo 3x3x da entrambi i lati otteniamo x+7â„5x+7â„5, che semplificato diventa xâ„â2xâ„â2, quindi ha una soluzione unica. 8. Vero o Falso: Una disequazione quadratica Ăš un tipo di disequazione di primo grado. o Risposta: Falso o Spiegazione: Una disequazione quadratica coinvolge il quadrato di una variabile e puĂČ essere di secondo grado o superiore, mentre una disequazione di primo grado coinvolge solo variabili elevate alla prima potenza. 9. Vero o Falso: Una disequazione del tipo 2(xâ3)<82(xâ3)<8 puĂČ essere risolta dividendo entrambi i membri per 22. o Risposta: Vero o Spiegazione: Dividendo entrambi i membri otteniamo xâ3<4xâ3<4, che puĂČ essere semplificato a x<7x<7 dopo l'aggiunta di 33 ad entrambi i membri. 10. Vero o Falso: Se abbiamo una disequazione del tipo xâ€4xâ€4 e xâ„3xâ„3, allora la soluzione Ăš x=4x=4. o Risposta: Falso o Spiegazione: La soluzione Ăš 3â€xâ€43â€xâ€4, il che significa che xx puĂČ essere qualsiasi numero tra 33 e 44, inclusi tutti i valori decimali in questo intervallo. Domande a Risposta Multipla: 11. Qual Ăš la soluzione della disequazione 2x+5>112x+5>11? a) x<3x<3 b) x>3x>3 c) x<8x<8 d) x>8x>8 o Risposta: b) x>3x>3 o Spiegazione: Sottraendo 55 da entrambi i lati otteniamo 2x>62x>6, quindi x>3x>3. 12. Quale delle seguenti Ăš una soluzione della disequazione 3xâ1â€83xâ1â€8? a) x=3x=3 b) x=1x=1 c) x=0x=0 d) x=4x=4 o Risposta: d) x=4x=4 o Spiegazione: Aggiungendo 11 ad entrambi i lati otteniamo 3xâ€93xâ€9, quindi xâ€3xâ€3. 13. Quale delle seguenti disequazioni Ăš equivalente a 2(x+1)>62(x+1)>6? a) 2x>62x>6 b) 2x+2>62x+2>6 c) x+1>3x+1>3 d) x>2x>2 o Risposta: c) x+1>3x+1>3 o Spiegazione: Distribuendo 22 otteniamo 2x+2>62x+2>6, quindi x+1>3x+1>3. 14. Qual Ăš la soluzione della disequazione 5xâ4<3x+75xâ4<3x+7? a) x<11x<11 b) x>11x>11 c) x<â11x<â11 d) x>â11x>â11 o Risposta: d) x>â11x>â11 o Spiegazione: Sottraendo 3x3x da entrambi i lati otteniamo 2xâ4<72xâ4<7, quindi 2x<112x<11 e infine x>â11x>â11. âŠâŠ. 15 Qual Ăš la soluzione della disequazione 2x+3â„5xâ12x+3â„5xâ1? a) xâ€â1xâ€â1 b) xâ„â1xâ„â1 c) x<2x<2 d) x>2x>2 o Risposta: c) x<2x<2 o Spiegazione: Sottraendo 5x5x da entrambi i lati otteniamo â3x+3â„â1â3x+3â„â1, quindi â3xâ„â4â3xâ„â4. Dividendo entrambi i lati per â3â3, ricordando di invertire il segno, otteniamo x<2x<2. 16 Quale delle seguenti Ăš una soluzione della disequazione 4xâ2â€2x+64xâ2â€2x+6? a) xâ€â2xâ€â2 b) xâ„â2xâ„â2 c) x<2x<2 d) x>2x>2 o Risposta: b) xâ„â2xâ„â2 o Spiegazione: Sottraendo 2x2x da entrambi i lati otteniamo 2xâ2â€62xâ2â€6, quindi 2xâ€82xâ€8 e infine xâ„â2xâ„â2. 17 Quale delle seguenti Ăš la soluzione della disequazione 3(xâ2)>93(xâ2)>9? a) x>3x>3 b) x>5x>5 c) x<3x<3 d) x<5x<5 o Risposta: b) x>5x>5 o Spiegazione: Dividendo entrambi i lati per 33, otteniamo xâ2>3xâ2>3, quindi x>5x>5. 18 Qual Ăš la soluzione della disequazione 2x+4â€102x+4â€10? a) xâ€2xâ€2 b) xâ„2xâ„2 c) x<2x<2 d) x>2x>2 o Risposta: a) xâ€2xâ€2 o Spiegazione: Sottraendo 44 da entrambi i lati otteniamo 2xâ€62xâ€6, quindi xâ€3xâ€3. Tuttavia, dovremmo tenere conto che 22 Ăš positivo, quindi la soluzione Ăš xâ€2xâ€2. 19 Quale delle seguenti disequazioni Ăš equivalente a 2xâ€82xâ€8? a) xâ„4xâ„4 b) xâ€4xâ€4 c) x>4x>4 d) x<4x<4 a. Risposta: b) xâ€4xâ€4 b. Spiegazione: Dividendo entrambi i lati per 22, otteniamo xâ€4xâ€4. 20 Quale delle seguenti Ăš una soluzione della disequazione 5(xâ3)>105(xâ3)>10? a) x<â1x<â1 b) x>â1x>â1 c) x>5x>5 d) x<5x<5 a. Risposta: c) x>5x>5 b. Spiegazione: Dividendo entrambi i lati per 55, otteniamo xâ3>2xâ3>2, quindi x>5x>5.