What is Science? Section 1.1

What Science Is and Is Not ► Science ► Organized way of using evidence to learn about the natural world

What Science Is and Is Not Cont’d ► Goal of Science: ► Investigate and understand the natural world ► Explain events ► Use explanations to make predictions that could be beneficial

Thinking Like A Scientist ► Step 1 ► Observation: ► Process of gathering info. about events or processes in a careful, orderly way

Thinking Like A Scientist Cont’d ► Step 2 ► Gathering info. from observations (data) ► 2 Types of Data ► 1. Quantitative: expressed as numbers ► 2. Qualitative: descriptive and involve characteristics that can’t easily be measured

Thinking Like A Scientist Cont’d ► Step 3 ► Make inferences based on data ► Inference ► Logical interpretation based on prior knowledge or experience

Thinking Like A Scientist Cont’d ► Step 4 ► Explain and interpret your evidence which leads to a… ► Hypothesis ► Proposed scientific explanation for a set of observations that can be tested

Hypothesis ► Must be proposed in a way that can be tested ► Tested by performing controlled experiments or by gathering new data

Explaining and Interpreting Evidence ► Do not copy ► Researchers often work in teams to analyze, review, and critique each other’s data and hypotheses. ► A review process helps ensure conclusions are valid. ► To be valid, a conclusion must be based on logical interpretation of reliable data.

What does science involve? 1. Asking questions 2. Observing 3. Making inferences 4. Testing hypotheses

Science as a Way of Knowing ► Scientific knowledge is always changing ► Good scientists are skeptics

Science and Human Values ► Decisions in science depend on: ► Society ► Economy ► Laws ► Moral principles ► We decide what and how things get done when we vote

Section 1-2

The Scientific Method Section 1-2 ► How do scientists test hypotheses? ► Controlled Experiments ► Must change only 1 variable at a time ► Why??????????

Designing an Experiment ► Steps: 1. Ask a question 2. Form a hypothesis 3. Set up a controlled experiment 4. Record/Analyze results 5. Draw conclusion

Designing an Experiment Cont’d ► Step 1: Asking a question ► Ex.) ► How do organisms come into being?

Designing an Experiment Cont’d ► Step 2: Forming a hypothesis ► Ex.) Spontaneous Generation ► Life could come from nonliving matter ► People thought maggots came from meat ► 1668, Redi proposed a different hypothesis ► Maggots came from eggs that flies laid on meat

Designing an Experiment Cont’d ► Step 3: Setting up a controlled experiment ► Manipulated Variable ► Deliberately changed ► Responding Variable ► Variable that is observed and that changes in response to the manipulation

Copyright Pearson Prentice Hall Designing an Experiment Redi’s Experiment Controlled Variables: jars, type of meat, location, temperature, time Covered jars Uncovered jars

Copyright Pearson Prentice Hall Designing an Experiment Redi’s Experiment Manipulated Variable: Gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear. Several days pass. No maggots appear.

Designing an Experiment Cont’d ► Step 4: Recording and analyze results ► Use written records of observations/data ► Use drawings when needed ► Use computers to analyze data ► Store data online for others to view

Designing an Experiment Cont’d ► Step 5: Draw a conclusion ► Use data to evaluate hypothesis and draw a conclusion ► Ex.) Redi’s results supported his hypothesis

Designing an Experiment Cont’d ► Finally Step 6: ► Investigations must be repeated ► Why???? ► To make sure results are correct

Repeating Investigations ► Needham ► Challenged Redi’s results ► Said that spontaneous generation could occur when conditions were right

Copyright Pearson Prentice Hall Repeating Investigations  Spallanzani's Test of Redi's Findings  Spallanzani's Test of Redi's Findings Gravy is boiled.

Copyright Pearson Prentice Hall Repeating Investigations  Spallanzani's Test of Redi's Findings  Spallanzani's Test of Redi's Findings Flask is open. Flask is sealed.

Copyright Pearson Prentice Hall Repeating Investigations  Spallanzani's Test of Redi's Findings  Spallanzani's Test of Redi's Findings  This backed up Redi’s findings Gravy is teeming with microorganisms. Gravy is free of microorganisms.

Repeating Investigations ► Louis Pasteur ► Disproved the hypothesis of spontaneous generation for sure ► Showed all living things come from other living things

Copyright Pearson Prentice Hall Repeating Investigations Pasteur’s Experiment Broth is boiled Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

Impact of Pasteur’s Work ► Saved the French wine industry b/c it gave them a way to preserve wine to keep it from souring ► Saved silk industry b/c it was becoming endangered by a silkworm disease ► Began to uncover the nature of infectious diseases, showing they came from organisms

Question ???? ► How does a scientific theory develop?

How A Theory Develops ► Evidence builds over time ► Hypothesis that is supported by it becomes so well supported ► It must then be considered a theory ► Theory ► Well-tested explanation that unifies a broad range of observations ► These can be changed; they are not concrete

What is Biology ► Bio/logy- ► Science that employs the scientific method to study living things

Characteristics of Life Fig p ► Made of cells ► Reproduce ► Based on a universal genetic code ► Grow and develop ► Obtain and use materials and energy ► Respond to environment ► Maintain a stable enviro. ► Change over time as a group

Big Ideas ► What do you think this means? ► All biological sciences are tied together they overlap each other p ► Go over pg with class

Branches of Biology ► Zoology ► Botany ► Paleontology

Levels of Organization ► Biosphere ► Ecosystem ► Community ► Population ► Organism ► Groups of cells ► Cells ► Molecules

Tools and Procedures ► What units are used to measure things? ► Metric System ► How do scientists analyze data? ► Use graphs

Tools and Procedures Cont’d ► Lab Techniques ► Cell Cultures- ► Group of cells grown in a nutrient solution from a single original cell ► Cell Fractionation- ► Solution is put into a centrifuge and spun to separate materials out by densities

Microscopes ► 2 Types ► 1. Light- produce images by focusing light rays ► 2. Electron- produce images by focusing beams of electrons

History of Microscope ► Use notes from West Greene here