Unit 1 Scientific Inquiry Essential Question #1 What role does science play in the study of life?

Miller & Levine: Ch. 1-The Science of Biology 1.1 What is Science (Pgs. 4-9) 1.2 Science in Context (Pgs ) Textbook References : Unit 1 Campbell: Ch. 1- Biology: Exploring Life 1.7 & 1.8 The Process of Science (Pgs. 9-10) 1.9 Biology and Everyday Life (Pg. 12)

Unit Vocabulary 1.Biology 2.Quantitative Data 3.Observation 4.Conclusion 5.Ethics 6.Hypothesis 7.Inference 8.Generalization 9.Controlled Experiment 10.Independent Variable 11.Stimulus 12.Dependent Variable 13.Theory 14.Control Group 15.Experimental Group 16.Qualitative Data 17.Metric System 18.Line Graph 19.Bar Graph 20.Scientific Methodology 21.Discovery Science 22.Hypothesis-Based Science 23.Inquiry

What is Science? The word is derived from a Latin verb meaning “to know”. It’s an organized way of gathering and analyzing evidence Science deals only with the natural world. Scientists look for patterns and connections among events.

What are the Goals of Science? Scientists aim for the best understanding of the natural world. –To provide explanations for natural events. –To use those explanations to understand patterns & make useful predictions.

The Process of Science Biology blends two main types of scientific exploration: – Discovery science – Hypothesis-based science Science as Inquiry: – All science explorations begin with a question – Science = “to know” in Latin – In order “to know” you must ask a question (inquire)

The questions are based on observations. – the use of senses to gather and record information about structures or processes. Recorded observations are called data

The Two Types of Data: Quantitative (think quantity) measurements – ex: height charts Qualitative (think quality) descriptions – ex: Jane Goodall and chimps

Discovery Science It is descriptive science. It describes natural structures or processes through observation and data collection Alexander Fleming and the discovery of penicillin

Steps of Discovery Science Ask a question Make observations Collect data and analyze Form a conclusion A logical conclusion based on observations is called an inference.

Example of an Inference Observation- the door bell rings Inference- somebody is waiting at the door Could the bell ringing infer something else? Generalization- a general conclusion based on many observations

Hypothesis-Based Science Used to explain the natural world. How does it differ from Discovery science? – You can describe and measure the growth of a plant toward light (discovery), but what causes this phenomenon? How can scientists explain the plant’s ability to detect and respond to the direction of the light (hypothesis-based)?

 Observations are made which lead to questions and inferences.  Hypotheses are formed based on our observations using deductive reasoning.  Experimentation is a way of gathering information/data as a means of testing our hypotheses.  Quantitative data: numerical information  Qualitative data: information in the form of words  Results and Conclusions use experimental data as evidence to support, refute, or revise the hypothesis being tested. The hypothesis must be testable The hypothesis must be falsifiable Scientific Methodology A universal approach to studying science by using deductive reasoning.

The Scientific Method Steps used to gather info. & answer questions. QUESTION RESEARCH FORM HYPOTHESIS EXPERIMENT ANALYZE RESULTS DRAW CONCLUSIONS

Observe and ask questions What is it that you would like to know? QUESTION

Gather information RESEARCH

Hypothesis- (an educated guess) -a possible explanation for your question -based on the info that you gathered -can be tested FORM HYPOTHESIS

Experiment- An investigation that tests your hypothesis Variable- Factors that can change in an experiment Constants- the variables that you control Independent Variable - the condition that is tested (the one variable that you alter) -it is the only factor that affects the outcome Dependent Variable -the condition that you observe or measure -results from changes made to the independent variable Control- - A standard used to compare your results (the absence of the independent variable) EXPERIMENT

charts tables graphs measurements observations Based on your results what is the answer to your original question? Can you accept your hypothesis? If not, you must reject it and start over! ANALYZE RESULTSDRAW CONCLUSIONS

Forming and Testing a Hypothesis Tigger went camping one night and made the following observation: “My flashlight doesn’t work!” – The question is obvious. Why doesn’t my flashlight work? A reasonable hypothesis could be that the batteries are dead.

Prediction If the batteries are dead and he replaces them with new ones, then the flashlight will work. If the results of the test do not support the hypothesis, other hypotheses can be formed and tested.

Observations:_______________________________ ___________________________________________ ___________________________________________ Hypothesis:_________________________________ ___________________________________________ ___________________________________________ Examine the picture to the right and assess your understanding of how biologists use scientific methodology to answer questions about the natural world.

› An observation is the act of noticing and describing events or processes in a careful, orderly way. › For example, researchers observed that marsh grass grows taller in some places than others. › This observation led to a question:  Why do marsh grasses grow to different heights in different places?

› After posing questions, scientists use further observations to make inferences, or logical interpretations based on what is already known. › Inference can lead to a hypothesis, or a scientific explanation for a set of observations that can be tested in ways that support or reject it. › For example, researchers inferred that something limits grass growth in some places. › Based on their knowledge of salt marshes, they hypothesized that marsh grass growth is limited by available nitrogen.

Can you determine the following? 1. Control Group: __________________________________ 2. Experimental Group: _____________________________ 3. Independent Variable: ____________________________ 4. Dependent Variable: _____________________________ Use the picture above to explain the experiment: _______________________________________________ _______________________________________________ _______________________________________________

› Testing a scientific hypothesis often involves designing an experiment that keeps track of various factors that can change, or variables.  Examples of variables include temperature, light, time, and availability of nutrients. › Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed. › All other variables should be kept unchanged, or controlled. This type of experiment is called a controlled experiment.

› It is important to control variables because if several variables are changed in the experiment, researchers can’t easily tell which variable is responsible for any results they observe. › The variable that is deliberately changed is called the independent variable.  also called the manipulated variable. › The variable that is observed and that changes in response to the independent variable is called the dependent variable  also called the responding variable.

› Typically, an experiment is divided into control and experimental groups. › A control group is exposed to the same conditions as the experimental group except for one independent variable. › Scientists set up several sets of control and experimental groups to try to reproduce or replicate their observations.

› For example, the researchers selected similar plots of marsh grass. All plots had similar plant density, soil type, input of freshwater, and height above average tide level. The plots were divided into control and experimental groups. › The researchers added nitrogen fertilizer (the independent variable) to the experimental plots. › They then observed the growth of marsh grass (the dependent variable) in both experimental and control plots.

Results: ________________________________________________ ________________________________________________ Analysis : ________________________________________________ ________________________________________________ Conclusion: Remember that your conclusion is the answer to your hypothesis. ________________________________________________ ________________________________________________

› Scientists choose appropriate tools for collecting and analyzing data. › Tools include simple devices such as metersticks, sophisticated equipment such as machines that measure nitrogen content, and charts and graphs that help scientists organize their data.

Scientists record experimental observations, gathering information called data. Quantitative data are numbers obtained by counting or measuring. In the marsh grass experiment, it could include the number of plants per plot, plant sizes, and growth rates. Qualitative data are descriptive and involve characteristics that cannot usually be counted. In the marsh grass experiment, it might include notes about foreign objects in the plots, or whether the grass was growing upright or sideways.

 In the past, data were recorded by hand.  Today, researchers typically enter data into computers, which make organizing and analyzing data easier. › This graph shows how grass height changed over time. › The grass in the experimental group grew taller than the grass in the control group.

 Scientists use experimental data as evidence to support, refute, or revise the hypothesis being tested, and to draw a valid conclusion. › Analysis- The marsh grass in the experimental group grew taller than the grass in the control group because grass growth is limited by the availability of nitrogen. › Conclusion- The hypothesis is accepted based on these results.  New data may indicate that the researchers have the right general idea but are wrong about a few particulars. In that case, the original hypothesis is reevaluated and revised; new predictions are made, and new experiments are designed.  Hypotheses may have to be revised and experiments redone several times before a final hypothesis is supported and conclusions can be drawn.

 Can you propose one possible source of error in the marsh grass experiment? Could there be another reason for the grass to grow taller in the experimental group? _________________________________ _________________________________ _________________________________

› Researchers must be careful to avoid errors in data collection and analysis. Tools used to measure the size and weight of marsh grasses, for example, have limited accuracy. › Data analysis and sample size must be chosen carefully. The larger the sample size, the more reliably researchers can analyze variation and evaluate differences between experimental and control groups.

 they are based on opinions  they are not based on your actual results  your sample size is too small  you over-generalize based on only a few tests  you do not have a control

TTheory ›a›an explanation of a natural phenomenon ›b›based on scientific evidence from many investigations ›r›results from continued support of a hypothesis.

copied from: A picture is worth a thousand words!

 Variables › what you measure in an experiment › dependent variable  measured variable  unpredictable change: we don’t know how it will change until we do the experiment  Y-axis › independent variable  manipulated variable  predictable change: it only changes because we chose how it would change  X-axis The effect of _____________ on _____________ INDEPENDENT DEPENDENT

 How does fertilizer affect the growth rate of plants? › we set up an experiment testing different amounts of fertilizer on different plants & measuring the growth (height) of the plants:  dependent variable (Y-axis)?  height of plants  independent variable (X-axis)?  amount of fertilizer The effect of _____________ on _____________ Amount of Fertilizer Height of Plants

 How does exercise affect heart rate of 10th grade student? › we set up an experiment testing different lengths of time of exercise (minutes) on the heart rate of students:  dependent variable (Y-axis)?  heart rate  independent variable (X-axis)?  minutes of exercise The effect of _____________ on _____________ Exercise Heart Rate

 What’s the favorite drink of students? › we set up an experiment surveying students and asking which is their favorite drink :  dependent variable (Y-axis)?  number of students  independent variable (X-axis)?  type of drink The effect of _____________ on _____________ Type of Drink How many students chose it

 Graphs › line graphs  graphing data that shows continuous change › bar graphs (or histograms)  graphing data that is in disconnected groups How’s a critter to choose?

How does elevation affect temperature? elevation temperature elevation (feet above sea level) temp. (°C) ft? 18 Line graph! 1200

Which drink do you like best? type of drink number of students CokePepsiwaterteaGatorade 0 drinknumber Coke1 Pepsi1 Water4 Iced tea4 Gatorade3 Favorite? Bar graph!

Essential Question #1 What role does science play in the study of life? By applying scientific methodology, biologists can find answers to questions that arise in the study of life.