Focus on California Life Science 7th Grade Unit 1 - Chapter 1 What is Life Science

Chapter The anatomy and physiology of plants and animals illustrate the complementary nature of ture and function . Physical principles underlie biological structures and functions . Scientific progress is made by asking meaningful questions and conducting careful tions . As a basis for understanding this concept and addressing the content in the other three strands , students should develop their own questions and perform investigations . Students will Comm the logical among hypotheses , science concepts , tests ed , data collected , and drawn from the scientific evidence . Communicate the steps and results from an investigation in written reports and oral This lood scientist is busy at work in a laboratory . What Is Life Science ?

vim . and What Is Science ?

Focus on the BIG Idea How do scientists make progress in understanding the natural world ?

Check What You Know Which of the following questions can be answered by scientific investigation ?

Explain your reasoning . a . How does the type of soil affect plant growth ?

What kind of music should I listen to ?

Do wool sweaters keep you warmer than cotton sweaters ?

Is life science more interesting than Earth science ?

Chapter The images shown here represent some of the Key Terms in this . chapter . You can use this vocabulary skill to help you understand the meaning of some Key Terms in this chapter . Academic Words academic words are words that are used frequently in classrooms . Look for the words below as you read this chapter . I Definition I Example Sentence concept An idea or thought , Each section in this textbook ( KAHN sept ) especially a general contains key . which are . 14 , 15 idea or understanding the section most important ideas . process A series of actions or Science is an ongoing of ( ses ) events a particular way discovery . is of doing things evidence Facts , figures , or signs Scientists propose explanations ( Ev uh ) to show that something based on evidence they gather . 18 exists or is true research , Careful study of a Research into the causes of cancer ( REE ) subject to discover new may lead to a cure . 21 facts or test new ideas Apply It ! Choose the word that best completes each sentence .

scale model controlled quantitative observation , Chapter Vocabulary Section science observing quantitative observation qualitative observation inferring predicting classifying making models Section ( life science biology organism development structure function complementary Section ( pug scientific inquiry hypothesis variable controlled experiment control manipulated variable responding variable operational definition data Build Vocabulary Online Visit web ( ode Chapter

Preview Text Structure The information in this textbook is organized with red headings and blue . You can preview these headings to help you take notes about what you read . Organize your notes by dividing a sheet of paper into three columns . Write the heading in the first column . Write a question in the second column . Look for important words in the heading to guide you in asking a question . Answer your question in the third column . The partially completed notes below are based on the first heading of Section in this chapter . Section The Study of Life Heading Question Branches of What are the There are many branches of life science . Life Science branches of but the branches overlap . life science ?

Molecular ofthe building blocks of cells information is from parents to offspring and environment of Apply It ! Review the notes above . Then answer the questions . What are the key words in the heading in the first column ?

What question has been asked about the heading ?

The answer says that the branches of life science overlap . What does this mean ?

when you read Section , take notes for all the headings . Also use this method to preview and take notes on Section .

Standards Investigation , Ideas and Scientific Evidence Does fertilizer make plants grow taller ?

yawning contagious ?

Do fresh eggs sink in water , but older eggs float ?

Does moss always grow on the north side of trees ?

Do brightly colored flowers attract more insects ?

Each of these questions relates to a common idea about living things . But are those ideas true ?

What is the evidence ?

In this investigation , you will use scientific methods to find out . Your Goal To design and conduct a scientific experiment to test whether a common idea about living things is true or false To complete this investigation , you must select one specific question to investigate determine the procedure you will follow to investigate your question collect data and use it to draw conclusions follow the safety guidelines in Appendix A Plan It ! Make a list of some common ideas you could explore . Then preview the chapter to learn what types of questions can be explored by scientific methods . When you select a question , write the procedure you will follow . After your teacher approves your plan , begin your experiment .

. Standards Focus Scientific progress is made by asking meaningful questions and conducting careful investigations . What skills do scientists use to learn about the world ?

Key Terms science observing quantitative observation qualitative observation inferring I predicting classifying making models scale model Go For . More on scientific thinking Visit Web Code 69 Thinking Like a Scientist Standards How Keen Are Your Senses ?

Your teacher has arranged for an unexpected event to occur . At the count ot three , the event will begin . List as many details as you can remember about the event . Compare your list with those of your classmates . Think it Over Observing How many details could you list ?

which of your senses did you use to gather information ?

Once , as i walked through thick forest in a downpour , I a chimp hunched in front of me . Quickly i stopped . Then i heard a from above . I looked up and there was a big chimp there , too . When he me he gave a loud . clear wailing call that in to threaten a animal . To my right i a large black hand shaking a branch and bright eyes glaring through the foliage . Then came another savage from behind . Up above . the big male began to sway the vegetation . i was . These words are from the writings of lane Goodall , a scientist who studies wild chimpanzees in National Park in Tanzania , Africa . What would you have done if you were in lanes shoes ?

Would you have screamed or tried to run away ?

lane did neither of these things . instead , she crouched down and stayed still so she wouldn startle the chimps . Not feeling threatened by her , the chimps eventually moved on . lane Goodall was determined to learn all she could about chimps . Her studies are an example of science in action . Science is a way of learning about the natural world . Science also includes all of the knowledge gained by exploring the natural world . Scientists use skills such as observing , inferring , predicting , classifying , and making models to learn more about the world and make progress . However , these skills are not unique to scientists . You , too , think like a scientist every day .

Observing lane Goodall has spent countless hours among the following them , taking notes , and carefully observing . Observing means using one or more of your senses to gather information . Your senses include sight , hearing , touch . taste , and smell . By using her senses , Jane learned what chimpanzees eat , what sounds they make . and even what games they play ! During her time in , lane made many surprising observations . For example , she observed how use sticks or long blades of grass as tools to fish out a tasty meal from termite mounds . Like lane , you use your senses to gather information . Look around you . What do you see ?

What do you hear and smell ?

You depend on your observations to help you make decisions throughout the day . For example , if it feels chilly when you wake up , you probably dress warmly . Observations can be either quantitative or qualitative . Quantitative observations deal with a number , or amount . Seeing that you have eight new in your inbox is a quantitative observation . Qualitative observations , on the other hand , deal with descriptions that can not be expressed in numbers . Noticing that a bike is blue or that a grape tastes sour are qualitative observations . ad . What senses can the skill of observation involve ?

FIGURE Observing By patiently observing chimpanzees , Jane Goodall learned many things about chimpanzee behavior . The smaller photo shows one of Jane earliest chimps use sticks as tools to fish for termites . Chapter Inferring One day , Jane Goodall saw something peculiar . She watched as ' a chimpanzee peered into a hollow in a tree . The chimp picked off a handful from the tree and chewed on them . Then it took the leaves out of its mouth and pushed them into the tree hollow . When the chimp pulled the leaves back out , lane saw the gleam of water . The chimp then put the wet leaves back in its month . What was the chimpanzee doing ?

Jane reasoned that the chimpanzee might be using the chewed leaves like a sponge to soak up water . Seeing the chimp chew on leaves , put them in the hollow , and then squeeze the liquid out is an example of an observation . But Jane went beyond simply observing when she reasoned why the chimpanzee was doing these things . When you explain or interpret the things you observe . you are inferring , or making an inference . Making an inference doesn mean guessing wildly . are based on reasoning from what you already know . knew that chimpanzees . like ' I , all other animals , need water , and that rainwater in tree hollows . She reasoned that the chimp was it using chewed leaves to get the water out of the tree . You , too , make inferences all the time . Because your brain processes observations and other infor mation so quickly . you may not even realize when you have made an inference . For example , if you see your friend smile after getting back an exam . you might infer that she got a good grade . inferences are not always correct , however . Your friends smile might not have to do with the test . Whatrs Inferring ?

FIGURE Inferring When you explain or interpret your observations , you are making ' an inference . Inferring List three , inferences you can make about this chimp .

Predicting Sometimes , lane could even predict what a chimp was going to do next . Predicting means making a forecast of what will happen in the future based on past experience or evidence . Through her observations , lane learned that when a is frightened or angry , its hairs stand on end . This response is sometimes followed by threatening gestures such as charging , throwing rocks , and shaking trees , or even an attack . Therefore , if lane sees a chimp with its hairs on end , she can predict that the chimp might attack her in a short time . She then leaves the area . Likewise . you would probably move away if you saw a dog growling or baring its teeth . Why ?

Because predicting is part of your everyday thinking . You might predict , for example , that your basketball team will win tonight game if you have always ' ha beaten the other team in the past . Predictions . of course , are not always correct . New players this year may increase the chimp , bare their other teams chances of winning . teeth when thev ' Predictions are a type of inference . An inference is any ' nation or interpretation . A prediction is an inference about the , future . Suppose you see a broken egg on the by a table . Which of the following statements is a prediction ?

The egg rolled off the table . Somebody walking by will step on the egg . Reviewing Math Algebra and Functions ! II Chimp Diet in May Analyzing Data Chimp Food This graph shows the diet of chimps at National Park during May of one year . Reading Graphs According to the graph , what foods do chimps eat ?

Interpreting Data Did chimps feed more on seeds or leaves during this month ?

Calculating What percentage of the diet did blossoms , seeds , leaves , and fruit make up ?

Predicting November is the main fishing season , when chimps spend a large part of their time eating . Predict how the percentage of foods might change in November .

Freon Classifying Field notes like these contain many details about a chimp daily activities . By grouping together all the information related to resting , climbing , or feeding , Jane can better understand the behavior . in nest feeds on ! fruit Wanders along , feeding on fruits lib ) feeding , climbs , and feeds on fruit again Travels I 100 , Resting Classifying What do chimps do all day ?

To find out , lane and her assistants followed the through the forest . They took detailed notes about the chimps behaviors . shows a short section of notes about , an adult male chimp . Suppose lane wanted to know how much time spent feeding or resting that morning . She could out by classifying actions into several categories . Classifying is the process of grouping together items that are alike in some way . For example , lane could group together all the information about feeding habits or his resting behavior . This would also make it easier to compare omeo actions to those of other chimps . For instance , she could determine if other adult males feed or rest as much as does . You , too , classify objects and information all the time . Classifying things helps you to stay organized so you can easily and use them later . When you put papers in a notebook , you might classify them by subject or date . And , you might have one drawer in your dresser for shirts and another for socks . Reading . How IS classifying objects useful ?

Climbing Making Models How far do chimpanzees travel ?

Where do they go ?

Sometimes , ane research team would follow a chimpanzee for many days at a time . Figure illustrates journey through the forest over the course of one day . The diagram is one example of a model . Making models involves creating of complex objects or processes . Models help people study and understand things that are complex or that cant be observed directly . Using a model like the one in Figure , lane and her assistants could share information that would otherwise be to explain . of Models Models are all around you . They include physical objects , such as globes or the sets used in your favorite show . Some models are generated by computer , like the ones some use to design new buildings . It important to keep in mind that models are only representations of the real object or process . Because some information may be missing from a model , you may not be able to understand everything about the object or process the model represents . FIGURE Making Models This map is a model that traces journey through the forest . It represents information that would be hard to explain in words . Notice the scale on the map . Interpreting Maps Estimate the total distance that traveled between his morning and evening nests . 11

FIGURE Model of a Virus This scale drawing of the human virus ( HIV ) shows the structures on its surface . The yellow knobs allow the virus to attach to a cell . Scientists use such models to develop ways to fight HIV . Section Assessment Scale Models A scale model accurately shows the tions between its parts . A scale is a proportion used in mining the relationship between a model and the object that it represents . You may be familiar with the scales on maps . A map may have a scale with the proportion of centimeter to kilometer . This means that centimeter on the map stands for kilometer in real Suppose a map has a scale of centimeter to 500 meters . The distance between two locations on the map measures 10 meters . To determine the actual distance in meters , you can perform the following calculation Distance traveled 10 A scale model may be bigger or smaller than the object it represents . For example , Figure shows a model of the human virus ( HIV ) which causes AIDS . Viruses are too small to see without a microscope . Therefore , the model is many times bigger than the actual virus . Models may be built to different scales . For example , a scale model of the Golden Gate Bridge built at a scale of centimeter to kilometer could in the palm of your hand . The bridge at a scale of centimeter to meter would be about as long as a basketball court . i What is a scale ?

leading Vocabulary Skill Academic Words Complete the following sentence to show that you understand the meanings of process and classifying . Classifying is the process in which Reviewing Key Concepts a . Listing Name skills that are important in thinking . Comparing and Contrasting How do observations differ from inferences ?

Classifying Is this statement an observation or an inference ?

The car must be ill . Explain your reasoning . 120 Something About Plants Take a walk through a park or garden with a family member . Make five qualitative observations and five quantitative observations about the plants you see . Then , make an inference based on your observations . Explain to your family difference between an observation and an inference .

Section The Study of Life i , Standards Focus 10 ing The anatomy and physiology How is Structure Related of plants and animals illustrate the to Function ?

complementary nature of structure . and function , Study the photo of the bird ' Physical principles underlie its biological structures and functions . Next . study the photos of the three food items below , Think It Over Standards How are the branches of life science related ?

Based on your what am some ' Me observations , which of the food meme ?

items do you think the bird ' feeds on ?

Explain your Key Terms ' life science biology ' organism development ' function i complementary In a laboratory , detectives are solving a crime by comparing the genetic makeup of different suspects . On a beach , a scientist studies the nesting behavior of sea turtles . Deep in a tropical rain forest , another scientist discovers a new kind of beetle . In a hospital laboratory , doctors study a deadly form of bird . At a cancer research institute . a team of scientists develops new ' treatments for a rare form of cancer . What do all of these ple have in common ?

All these people are working in the of life science . Life science is the study of living things . Another name for life science is biology . The word biology comes from two Greek words . Bios means and logos means reason or ' the study Thus biology is the study of life . Biologists are scientists who study living things . Biologists study all kinds of living things . The general term for a living thing is an organism . An organism may be an animal , a plant , a fungus or a ' Chapter ! 013

study organisms in their environment . Life Scientists at Work You can find life scientists at work in such diverse places as forests , laboratories , zoos , and museums . ye Go , For Links on careers in life science Visit Web Code 146 Molecular biologists study the chemicals in cells . Entomologist study insects . Physiologists study the structure and function of organisms . Branches of Life Science Biologists can work outside or in a laboratory . They may work for universities , private companies , or government agencies . Biologists . like other scientists , usually work as part of a team studying a common topic . Life science includes many different branches , or fields of study . Molecular biology , genetics , physiology , and ecology are just some of life science . Molecular biology is the study of the chemical building blocks of cells . Genetics is the study of how information about Organisms is passed from parent to spring . Physiology is the study of the structures and functions of organisms . Ecology is the study of how organisms interact with each other and with their surroundings . Other branches of life science include cell biology , plant biology , and ology . What do you think these involve ?

Though life science can be divided into branches , the different of study often overlap . For example , standing what controls plant development relies on concepts from molecular biology and plant biology . Progress in one oflife science often contributes to progress in another .

Big Ideas in Life Science Biologists investigate an incredible range of questions . But underlying all of their work are certain big ideas , or concepts . These big ideas connect the study of living things . It is helpful to keep these big ideas in mind as you study life science . As you read this textbook , notice how they come up again and again . The big ideas in life science include the following Organisms are diverse , yet share similar characteristics . Groups of organisms change over time . The structure and function of organisms are ' Organisms operate on the same physical principles as the rest of the natural world . Diverse but Similar come in a great variety of shapes and sizes , from microbes to giant redwood trees and blue whales . Although living things vary greatly , they have many basic similarities . All organisms are made up of tiny building blocks called cells . Cells are far too small to be seen by the eye , but they carry out all the activities for life . Some organisms are composed of just one cell . Others contain trillions . The chemical composition of all living things is remarkably similar . Every living thing is made up mainly of water , a relatively simple compound . But organisms also contain highly complex chemicals . For example , most organisms contain DNA , the chemical that controls all the activities of the cell and allows organisms to pass information to their offspring . All living things require energy . Plants are able to capture energy from sunlight . Other organisms must obtain energy by eating other living things . Organisms can grow and develop . Growth is the process by which an organism becomes larger . Development is the process of change that causes an organism to become more complex during its lifetime . And , all living things reproduce , FIGURES or produce more of their own kind . Diversity and of Life Finding How is development different from This arrow flog and mushroom ' growth ?

very different . However , both are ce , use energy , grow , develop , and reproduce . 15 FIGURE Animal Eyes Eyes come in many shapes , sizes , and , in some cases , numbers . Although each of these animals sees things differently , all of their eyes operate on similar physical principles . Inferring How do you think the structure of each eye helps the organism to function ?

160 A Octopus A Fly Change Over Time The characteristics of any group of organisms can change over time . The gradual process of change that occurs in groups of organisms is called evolution . Evolution differs from the growth and development that occurs in an individual lifetime , such as when a pole becomes a frog . Evolution is a process that occurs over many generations . often over millions of years . Complementary Structure and Function The form of each living thing is closely related to the way that it lives . In other words , the structure of an organism allows it to function . Structure is the way that an organism is put together as a whole . Functions are the processes that enable an organism to survive . The structure and function of an organism are complementary , or work together to meet the needs of the organism . Look at the owl and eyes in Figure . Owls are adapted to life at night , when they actively hunt for food . An owl large eyes allow it to see when there is little light . In contrast , see well in bright light . Flies have compound eyes , meaning that each eye is made up of thousands of smaller units . Compound eyes are very effective in detecting even the slightest making very hard to catch ! Physical Principles Scientists once questioned whether ing things operate on the same set of rules as the rest of the natural world . Did living things have unique qualities that could not be explained by chemistry or physics ?

But today scientists know that life follows the same rules , or principles , as the rest of nature . For example , the principles of chemistry explain the that allow plants to capture the sun energy . Chemical processes also explain how animals digest their food . And the rules of heredity are based on the chemical structure of DNA .

A Cat A Lizard The principles of physics also help explain life processes . Consider , for example . the relationship between the physics of light and the way that eyes function . To understand how eyes function , scientists must know what light is and how light travels . Scientists can compare the structure of an eye to that of a camera . Like a camera , an eye uses a lens to focus light and form an image . The principles that allow a camera to take a picture also allow an eye to see . Compare the variety of eyes in Figure . Although each of the animals may see slightly differently , all of the eyes operate on similar physical principles . Section Assessment Target Reading Skill Preview Text Structure When you took notes on Section what question did you ask for the heading ' Home Activity Change Over Time ?

What was your answer ?

Reviewing Key Concepts Explain to a family a . Defining What is life science ?

What ' and . Describing List three branches of life The 009 500 magazines for photos of organisms that illustrate this concept . Find five examples to show your family member . Describe how a structure on each of the organisms is adapted to its function . science and describe what is studied in each . Making Judgments Your friend wants to be a plant biologist and says she only needs to take courses in plant biology . Why might it be a good idea for your friend to study other of life science as well ?

What are four big ideas in life science ?

Comparing and Contrasting What are some ways that a cat and a tree are similar ?

What are some ways they are different ?

17 Scientific Inquiry , Standards . Students will communicate the logical connection among hypotheses , science concepts , tests conducted , data collected , and conclusions drawn from the scientific evidence . What is scientific inquiry ?

What makes a hypothesis testable ?

Key Terms scientific inquiry hypothesis variable ' controlled experiment manipulated variable responding variable control I operational definition data communicating A snowy tree cricket 180 What Can You Learn About Mealworms ?

Study mealworms in a tray . Use a magnifying glass to see their structure more clearly . Observe the ' example , how they move or eat . Think It Over Posing Questions Write three questions you have about and their functions . How could you find out the answers ?

Chirp , chirp , chirp . it is one of the hottest nights of summer and your bedroom windows are wide open . On most nights , the quiet chirping of crickets gently lulls you to sleep , but not tonight . The noise from the crickets is almost deafening ! Why do all the crickets in your neighborhood seem mined to keep you awake tonight ?

Could the crickets be ing more because of the heat ?

How could you out ?

As you lie awake , you are probably not thinking much about science . But , in fact , you are thinking just as a scientist would . You made heard the loud chirping of the crickets and felt the heat of the summer night . Your observations led you to infer that heat might cause increased chirping . You might even make a prediction If its cooler tomorrow night , the crickets will be quieter . The Scientific Process You might not know it , but your questioning can be the start of inquiry . inquiry refers to the diverse ways in which scientists investigate the natural world and propose explanations based on the evidence they gather . If you have ever tried to out why a plant has wilted , then you have used inquiry . Similarly . you could use inquiry to out whether there is a relationship between the air temperature and crickets chirping .

Posing Questions inquiry often begins with a problem or question about an observation . In the case of the crickets , your question might be Does the air temperature affect the chirping of crickets ?

Of course , questions dont just Science ?

come to you from nowhere . Instead , questions come from experiences that you have and from observations and that you make . Curiosity plays a large role as well . Think of a time that you observed something unusual or unexpected . Chances are good that your curiosity sparked a number of questions . Some questions can not be investigated by inquiry . Think about the difference between the two questions below . Does my dog eat more food than my cat ?

i Which makes a better cat or a dog ?

crickets chirp more when the temperature le higher . The question is a question because it can be answered by making observations and gathering evidence . For example , you could measure the amount of food your cat and dog each eat during a week . In contrast , the second question has to do with personal opinions or ues . inquiry can not answer questions about personal tastes or judgments . Developing a Hypothesis How could you explain your observation of noisy crickets on that summer night ?

Perhaps crickets chirp more when the is higher , you think . in trying to answer the question , you are in fact developing a hypothesis . A hypothesis ( plural hypotheses ) is a possible tion for a set of observations or answer to a question . In this case , your hypothesis would be that cricket chirping increases at higher air temperatures . In science , a hypothesis must be testable . This means that researchers must be able to carry out investigations and gather evidence that will either support or disprove the hypothesis . trials will be needed before a hypothesis can be accepted as true . WAN ! em what is a hypothesis ?

FIGURE 10 Developing Hypotheses A hypothesis is one possible way to explain a set of observations . Developing Hypotheses Propose another hypothesis that could explain the observation that crickets seem to be noisier on some nights than others . Chapter 19

Controlling Variables Suppose you are designing an experiment to determine whether different varieties of apples contain the same number of seeds . What is your manipulated variable ?

What is your responding variable ?

What other variables would you need to control ?

FIGURE 11 A Controlled Experiment In this controlled experiment , the experimental group crickets are tested at , and . The students are using the same kinds of containers , leaves , thermometers , and crickets . The manipulated variable is temperature . The responding variable is cricket chirps per minute at each temperature . Designing an Experiment Hypotheses lead to predictions that can be tested . In this case , your prediction would be , If the temperature increases , crickets will chirp To test your prediction , you will need to observe crickets at ferent air temperatures . All other variables , or factors that can change in an experiment , must be exactly the same . Other include the kind of crickets , the type of container you test them in , and the type of thermometer you use . By keeping all of these variables the same , you will know that any in cricket chirping must be due to temperature alone . An experiment in which only one variable is manipulated at a time is called a controlled experiment . The one variable that is purposely changed in an experiment is called the manipulated variable ( also called the independent variable ) In your cricket experiment , the manipulated variable is the air temperature . The factor that may change in response to the manipulated variable is called the responding variable ( also called the dependent variable ) The responding variable here is the number of cricket chirps . In life science , a controlled experiment often has a control . A control is a part of the experiment to which you can pare the results of the other tests . In the control , the conditions are the same except for the manipulated variable . For the cricket experiment , you would test your control crickets at a constant temperature . That way , you can better recognize the effects of increased temperature on chirping . Another aspect of a experiment is having clear operational . An operational is a statement that describes how to measure a variable or a term . For example , in this experiment you would need to determine what sounds will count as a single chirp .

Experimental Group Data ii Number of CME per Minute Cricket Collecting and Interpreting Data For your experiment , you need a data table in which to record your data . Data are the facts , and other evidence gathered through . A data table is an organized way to collect and record observations . After the data have been collected , they need to be interpreted . A graph can help you interpret data . Graphs can reveal patterns or trends in data . Drawing Conclusions A conclusion is a summary of what you have learned from an experiment . In drawing your sion , you should ask yourselt whether the data support the hypothesis . You also need to consider whether you collected enough data . After reviewing the data , you decide that the evi supports your original hypothesis . You conclude that cricket chirping does increase with temperature . It no wonder that you have trouble sleeping on those warm summer nights . Communicating An important part of inquiry is communicating your results . Communicating is the sharing of ideas and experimental with others through writing and speaking . For example , scientists can give talks at meetings and publish articles in journals and on the . When scientists communicate their research , they describe the logical connections between their procedures and results . Other scientists can then repeat and build on their experiments . is 20 Temperature ( FIGURE 12 Collecting and interpreting Data A data table helps you organize the information you collect in an experiment . Graphing the data may reveal patterns . interpreting Data Did all of the crickets chirp more at than at 20 Did you use the data table or the graph to answer this question ?

21 Go active git ! For . The Nature of Inquiry activity Visit web Code Pose Questions Form a Communicate . I sun 13 Scientific inquiry There is no set path that a inquiry must follow . Observations at each stage of the process may lead you to modify your hypothesis or experiment . Conclusions from one experiment often lead to new questions and experiments . Design an Draw Experiment Conclusions Cone and Interpret Data The Nature of Inquiry inquiry usually doesn end once a set of experiments is done and results are communicated . Often , a inquiry raises new questions , that lead to new hypotheses and experiments , as shown in Figure 13 . Section Assessment ( Reviewing Key Concepts a . Defining the term inquiry . Explaining A friend claims that pea plants grow faster than corn plants . Could you investigate this idea through inquiry ?

Explain . Problem Solving What kind of data would you need to to do this experiment ?

a . Reviewing What is meant by saying that a hypothesis . must be testable ?

Developing Hypotheses Every time you and your friend study for an exam while listening to classical music , both of you do well on the exam . What testable hypothesis can you develop from your observations ?

Vocabulary Skill Academic Words Explain why evidence is an important part of research . I I 226 Section For Links on laboratory safety Visit Web Code Safety in he all the directions . Also , review the general safety guidelines in Appendix A , including those related to the equipment you will use . If anything is unclear , be prepared to ask your A iFOR A Standards Focus , Standards Warm Up Scientific progress is made by asking meaningful questions and ' Safety conducting careful investigations . Equipment In YOU ! SChOOl ?

As a has ' Look around your classroom or concept and addressing the tent in the other three strands , any students should develop their eq ' own questions and perform . Draw a floor plan of the room or building and clearly label where a each item is located . is preparation important , when carrying out scientific Th ' investigations in he ab and Predicting Why is it important to know in the field ?

where safety equipment is located ?

What should you do if an accident occurs ?

You and your family have just arrived at a mountain cabin for a a vacation . The view of the mountaintops is beautiful . and the fresh scent of pine trees the air . In the distance , you can glimpse a lake through the pines . You put on a bathing suit and head down the trail toward the lake . The sparkling , clear water looks inviting . You re tempted to jump in and swim . However , you wait for the rest of your family to join you . It is safe for a person to swim alone . Safety During Investigations lust as when you go swimming , you have to take steps to be safe during any investigation . Good preparation helps you conduct careful investigations by planning for safety . Do you know how to use lab equipment ?

What should you do if something goes wrong ?

Thinking about these questions ahead of time is an important part of being prepared . Preparing for the Lab Preparing for a lab should begin the mine day before you will perform the lab . It is important to read . 31 through the procedure carefully and make sure you understand INKS teacher about it before you begin the lab . Chapter 23

Performing the Lab Whenever you perform a science lab , always follow your teacher instructions and the textbook directions exactly . You should never try anything on your own without asking your teacher . Keep your work area clean and organized . Also , do not rush through any of the steps . Finally , always show respect and courtesy to your teacher and . classmates . Labs and activities in this textbook include the safety bols shown on the next page . These symbols alert you to ble dangers in performing the lab and remind you to work carefully . They also identify any safety equipment that you , should use to protect yourself from potential hazards . The symbols are explained in detail in Appendix A . Make sure you are familiar with each safety symbol and what it means . 14 Safety in the Lab Good preparation for an experiment helps I you stay safe in the laboratory . Observing List three precautions each student is taking while performing the labs . Wear safety goggles to protect your eyes from chemical splashes , glass breakage , and sharp objects . wea , an apron to puma yourself and your clothes i from chemicals . Wear ' gloves when handling hot objects . I Keep your work area clean and uncluttered . I Wear . shoes when working Make sure electric in the laboratory . cords are untangled and out of the way . 240

Procedures When you have finished a lab , clean your work area . Turn off and unplug equipment and return it to its proper place . Dispose of any wastes as your teacher instructs you to . Finally , wash your hands thoroughly . Safety in the Field You work in the whenever you work example , in a forest , park , or schoolyard . Always tell an adult where you will be Never carry out a investigation alone . Ask an adult or classmate to go with you . Possible safety hazards outdoors include such things as severe weather , traffic , wild animals , and poisonous plants . Planning ahead can help you avoid some hazards . For example . the weather report can alert you to severe weather . Use mon sense to avoid any potentially dangerous situations . Reading What should you do with equipment at the end ' of a lab ?

Wear plastic gloves to protect your skin when handling animals . plants , or chemicals . Handle live animals lie back long hair and plants with care . to keep it away from flames , chemicals , or equipment . Safety Symbols ( 03 Eli A Safety Goggles Lab Apron Breakage Gloves Plastic Gloves Heating Flames No Flames Corrosive Chemical Poison Fumes Sharp Object Animal Safety Plant Electric Shock Physical Safety Disposal Hand Washing General Safety Awareness 25

Case of Emergency ALWAYS NOTIFY TEACHER ?

What to no i Bum Immerse burns in cold ' 15 With a clean direct pressure to the wound to stop bleeding . Flush the skin with ' 98 amounts of water , Flush the ' amounts large in ' ye Seek ' attention . FIGURE 15 In Case of an Accident Good preparation and careful work habits can go a long way toward making your lab experiences safe ones . But , at some point , an accident may occur . A classmate might accidentally knock over a beaker or a chemical might spill on your sleeve . Would you know what to do ?

When any accident occurs , no matter how minor , notify your immediately . Then . listen to your teacher directions and carry them out quickly . Make sure you know the location and proper use of all the emergency equipment in your lab room . Knowing safety and procedures beforehand will prepare you to handle accidents properly . Figure 15 lists some procedures you should know . Reading Why is knowing the location of ' emergency equipment important ?

These tips can help guide your actions during emergency situations . Remember , always notify your teacher immediately if an accident occurs . OD Target Reading Skill Preview Text Structure Use your notes to help answer the questions below . Reviewing Key Concepts a . Reviewing Why is good preparation important in lab investigations ?

Identifying Identify two steps you should take to prepare for a lab . Predicting What might happen if you did not follow the steps you in Question ( a . Describing What should you do immediately after any lab accident ?

Applying Concepts Your lab partner cuts herself and stops the bleeding with a tissue from her pocket . Did she follow the proper procedure ?

Explain . 260 Section ' Assessment . Reading , Writing Relating Cause and Effect Explain how your partner might have prevented the accident if she had been more familiar with the safety symbols on page 25 . Writing in Science ! clear .

, Problem How can cut flowers stay fresher for a longer . period of time ?

Skills Focus developing hypotheses , designing experiments , drawing conclusions Suggested Materials plastic cups cut flowers spoon water sugar Design a Plan . Plants have structures that function in the transport of materials . You have just been given a bouquet of cut flowers . You ber once seeing a gardener put some sugar into the water in a vase before putting ers in . You wonder if the sugar is a material that helps flowers stay fresh longer . Write a hypothesis for an experiment you could form to answer your question . Working with a partner , design a controlled experiment to test your hypothesis . Make a list of all of the variables you will need to control . Also decide what data you will need to collect . For example . you could count the number of petals each flower drops . Then Keeping Flowers Fresh Analyze and Conclude . Developing Hypotheses What hypothesis did you decide to test ?

On what information or experience was your hypothesis based ?

Designing Experiments What was the manipulated variable in the experiment you performed ?

What was the responding able ?

What variables were kept constant ?

Graphing Use the data you collected to cre ate one or more graphs of your experimental results . For more on creating graphs , see the Skills Handbook . What patterns or trends do your graphs reveal ?

Drawing Conclusions Based on your graphs , what conclusion can you draw about sugar and cut flowers ?

Do your results support your hypothesis and what you know about plant structure ?

Why or why not ?

Communicating In a paragraph , describe which aspects of your experimental plan were difficult to carry out . Were any variables hard to control ?

Was it difficult to collect accurate data ?

What changes could you make to improve your experimental plan ?

write out a detailed experimental plan for your teacher to review . If necessary , revise your plan according to your teacher instructions . Then set up your experiment and begin collecting your data . More to Explore Make a list of some additional questions you would like to investigate about how to keep cut flowers fresh . Choose one of the questions and write a hypothesis for an experiment you could perform . Then design a controlled experiment to test your hypothesis . Obtain your teacher mission before carrying out your investigation . 27

Chapter Thinking Like a Scientist ( Key Concepts Scientists use skills such as observing , inferring , predicting , classifying , and making models to learn more and make progress . Key Terms science observing quantitative observation qualitative observation inferring predicting classifying making models scale model The Study of Life ( Key Concepts . Life science can be divided into branches the different of study often overlap . The big ideas in life science include the following Organisms are diverse , yet share similar characteristics . Groups of organisms change over time . The structure and function of organisms are complementary . Organisms operate on the same physical principles as the rest of the natural world . Key Terms life science biology organism development structure function complementary 280 Study Guide progress is made by asking meaningful questions and conducting careful investigations . Scientific Inquiry Key Concepts Scientific inquiry refers to the diverse ways in which scientists investigate the natural world and propose explanations based on the evidence they gather . In science , a hypothesis must be testable . This means that researchers must be able to carry out investigations and gather evidence that will either support or disprove the hypothesis . Key Terms scientific inquiry hypothesis variable controlled experiment manipulated variable responding variable control operational data communicating Safety in the Laboratory Key Concepts Good preparation helps you conduct careful scientific investigation by planning for safety . When any accident occurs , no matter how minor , notify your teacher immediately . Then , listen to your teachers directions and carry them out quickly .

) Target Reading Skill To help you review part of Section I , copy and complete the graphic organizer at the right . Hypothesis Reviewing Key Terms Choose the letter of the best answer . The process of change that occurs during an organisms life that produces a more complicated organism is called structure . function . development . variable . When you note that a rabbit has white fur , you are making a quantitative observation . I ) qualitative observation . prediction . model . Music stores ' to the A type of , country , folk , and so on . This is an of observation . inferring . posing questions . classifying . statement that describes how to measure a variable or a term is 2101 ) controlled variable . manipulated variable . hypothesis . operational . In labs in this book . which of the following indicates the danger of breakage ?

ha tin Developing a For Complete the following sentences so that your answers clearly explain the Key Terms . 10 . Studying how the human body works and how different animals interact with one another are examples of topics in life science , which is . Obtaining oxygen is an example of a function , which is a process that . Noticing how much food is on your lunch tray is a quantitative observation because Recording how many times your dog eats each day and how much he eats are examples of collecting data , which are Giving a talk about the results of a project is an example of communicating because Writing in Science , Saul What Is Science ?

29 and Assessment Checking Concepts skins 11 . List skills that a scientist uses to learn use the data tame to ' more about the world . Question 12 . When you observe , what are you a controlled to doing ?

find out how walking and running ( ted their . 13 . How are models useful to scientists ?

can in your own words , explain what is meant by Effect of Activity on Heart Rate the statement Physical principles underlie ( in beats per minute ) biological structures and functions . Hunk . arm . 15 . What is a hypothesis ?

Why is it important to ( attest ) running ) develop a hypothesis that is testable ?

90 16 . In an experiment , why is it important to 100 control all variables except one ?

I , identify three things that you should do to 120 prepare for a lab . 22 . Controlling Variables What is the Thinking variable in this ?

a is ing ' th . SIl ) to 23 ' Developing Hypotheses what th . i might this experiment be testing ?

eir functions . contrast and quantitative . 20 ' suppose you home to the 25 . Designing Experiments Design a controlled . scene below . What can you infer happened , to determine which activity has while you were gone ?

more of an effect on a person heart rope or doing . 26 . Drawing Conclusions What do the data indicate about the increased physical activity and heart rate ?

Standards Investigation Performance Assessment Create a poster that summarizes your experiment for the class . Your poster should include the question you tested . how 21 . Sowing you would like to you tested it , the data you collected , and what out which brand of glue 01 conclusion you drew from your experiment . What what variables would you need to in problems did you encounter while your ?

your experiment . Is additional testing necessary ?

300 Standards Practice Choose the letter of the best answer . During a lab , if you spill a chemical on your skin , you should A apply pressure to the area . rub the chemical off with a clean tissue . the skin with large amounts of water . throw the chemical in a waste basket . Use the table below to answer Questions . Animals in a Field Grasshoppers Birds Spiders . Which statement accurately expresses what happened in the between July and August ?

A The numbers of all the animals increased . The number of grasshoppers increased . The number of spiders decreased . The number of birds stayed the same . Which of the following statements about the data is true ?

A In July , there were more grasshoppers than birds . In August , there were more birds than spiders . Between July and August , the number of grasshoppers increased by 500 . in both months , there were more spiders than grasshoppers . Which of the following is a logical question that a scientist might pose based on the data in the table ?

A What killed off the spiders in the ?

Are spiders feeding on grasshoppers ?

Do all birds south for the winter ?

Are grasshoppers related to beetles ?

Success Tracker It . Your brother has a cold and you think you will probably get a cold , too . Which of the following are you doing ?

A posing a question based on an inference predicting based on an observation making a model based on an observation designing a controlled experiment . Which of the following statements about structure and function in organisms is NOT true ?

A An organism functions are the processes that enable it to survive . An organism contains structures that are related to its functions . All organisms have the same structure and function . An organism needs energy to carry out its functions . BIG Idea . Read each question and explain whether it can be answered by conducting a investigation . I . Can dogs see in the dark ?

II . How did pet dogs develop from wild dogs ?

Ill . Which type of dog is the most fun ?

IV . How does a dog tail help it survive ?

Select one question that can be investigated . State a hypothesis . Then describe how you might conduct a investigation to test your hypothesis .