Chapter 1 – Biology: The Study of Life Section 1.2 – The Methods of Biology p. 11-18

Answer this question… Why do earthworms crawl to the surface after it rains?

Observing + Hypothesizing Curiosity is often what motivates biologists to try to answer simple questions about everyday observations The knowledge obtained when scientists answer one question often generates other questions or proves useful in solving other problems

Scientific Methods Common steps that scientists use to gather information and answer questions No “fixed” set of steps to follow Usually begin with an observation Something seen that peaks a scientist/person’s curiosity You want to know “why”

Hypothesis An explanation for a question or a problem that can be tested Formed once the observations are made to explain the observations Many hypotheses can be formed in any investigation

Experimenting An experiment is generally an investigation to test a hypothesis by collecting information under controlled conditions

Parts of an Experiment Control Group Experimental Group Part of experiment that is standard Used for comparison Experimental Group The “test” group Receives an experimental treatment

Experimental Conditions Independent variable The one factor that was changed in the two groups For example, adding fertilizer to plants Dependent variable An observed or measured second condition as a result of the independent variable For example, the plant’s growth rate

Tools used in Experiments Beakers Test tubes Petri dishes Microscopes Spectrophotometers

Lab Safety Importance? To minimize hazards Safety symbols

Data gathering Data Information obtained from investigations Two types: Numbers Words

Data analysis Purpose? So the scientist can come up with a conclusion Was the hypothesis supported by the data Was it not supported? Are more data needed?

Reporting + Verifying data By reporting data, scientists can examine one another’s work Published in scientific journals Scientists can then verify the results by repeating an experiment If the results are the same, the hypothesis can then be accepted by the scientific community

Theory An explanation of a natural phenomenon that is supported by large body of scientific evidence obtained from many different investigations and observations Examples: The Cell Theory The Theory of Evolution by Natural Selection Theory of Relativity Big Bang Theory Atomic Theory

Laws/Principles Facts of nature that are generally known to be true Examples: Law of Gravity