The Science of Biology Chapter 1

Biology is… Bios – life -logy – study of The science that seeks to understand the living world

Science is… an organized way of using evidence to learn about the natural world

The goal of science is to… Investigate and understand the natural world Explain events in the natural world Use those explanations to make useful predictions

Scientific thinking Begins with observation Collecting data *quantitative *qualitative Use data to make inferences- logical interpretation based on prior knowledge or experience

1.2 How Scientists Work Designing an experiment 1. Identify problem 2. Get background info.-Research 3. Form a hypothesis 4. Set up controlled experiment 5. Collect/analyze data 6. Form your conclusion 7. Publish results

A proposed scientific explanation for a set of observations Hypothesis An educated guess A proposed scientific explanation for a set of observations

Independent Variable Manipulated variable The one that is changed by the scientist

Dependent Variable Responding variable The one that is observed or measured Changes in response to the manipulated variable

Constant (controls) The things that you hold constant throughout the experiment

What is the effect of temperature on solubility?

Review Science is an organized way of using evidence to learn about… 3 goals of science How do scientists think? How do scientists work?

Think about this question…. Does the amount of sleep a student gets affect how well the student does in school? Form a hypothesis Identify the independent variable Identify the dependent variable Label the x and y axes of a graph with the correct variables.

FLIES on MEAT What was Redi’s hypothesis? (pg.9) Why did he design an experiment that tested only one variable?

Scientists keep written records of their data, observations Scientists use the data from an experiment to evaluate the hypothesis and draw a valid conclusion (accept or reject hypothesis)

Scientists publish and repeat experiments Important to write procedure so it can be repeated Needham and Spallanzani (mid- 1700s)

John Needham Claimed spontaneous generation could occur under right conditions Heated gravy in sealed container After a few days found “animalcules” What did he infer?

Lazzaro Spallanzani Needham didn’t heat samples enough Boiled 2 containers of gravy Sealed one and left the other open What do you think happened to the 2 containers of gravy?

Sometimes it is not possible to do an experiment ethical considerations voluntary human subjects animal-based research

Theory A well-tested explanation that unifies a broad range of observations Helps scientists make accurate predictions about new situations How does a theory compare with a hypothesis?