1-1 What Is Science? Biology: The study of life!

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1 1-1 What Is Science? Biology: The study of life! The goal of science is to understand and be able to make predictions about the natural world. 1. Science is the process of trying to understand the natural world. 2. The word science also referres to the body of knowledge gained through scientific investigation. The scientific method is a series of actions commonly followed by scientists in attempting to understand the natural world. Scientific investigation begins with observation. An inference is an educated guess based on observation and prior knowledge.

2 Explaining and Interpreting Evidence -A hypothesis is a testable educated guess or inference. -A null hypothesis predicts that manipulation of the independent variable will have no effect on the dependent variable. An alternative hypothesis predicts that manipulation of the independent variable WILL have an effect. -The independent variable is the variable that is manipulated or made different between groups. -The dependent variable is the one that may respond to the independent variable and is measured as results. -A controlled experiment is one where the scientist attempts to keep all variables the same except one. -The control group is a group in an experiment where the independent variable is not manipulated. It functions for comparison with the experimental group(s), in which the independent variable is manipulated. -Quantitative data is measuruable in numbers. Qualitative data must be described. -Science depends on the scientific integrity of the scientist to do everything possible to control all variables in an experiment, eliminate bias in experimental design and analysis, and never fabricate or falsify data to so that 2 what has been discovered can be considered valid and true.

3 Science as a Way of Knowing -Analysis and conclusions must be performed with precission and integrity to be accepted as accurate and true! -The results of one experimet prove nothing! Only when repeated many times and when all predictions based on the hypothesis hold true can it be considered proof of validity. -The results of an experiment may support the hypothesis by suggesting it is true. The results of an experiment may refute the hypothesis by suggesting it is not true. -No matter the experimental results, they must be communicated to the rest of the scientific community to be varified and added to the scientific body of knowledge. Even if the hypothesis is not supported! -Scientists must be skeptical and critical of other scientists (peer review) as well as themselves to maintain scientific integrity and ensure scientific discoveries are the true. -Experimental results must be repeatable to be considered valid and true. One experiment proves nothing! -Scientific publications must undergo peer review (skeptical & critical) to maintain scientific integrity and ensure that scientific knowledge is true. 3

4 The Scientfc Method Null Hypothesis Alternative Hypothesis Practice recreating this general flowchart from memory! Repeat! Other Thoroughly Tested & Widely Accepted Hypotheses 4

5 Writng a Hypothesis (If, and we, then) A hypothesis specifc to an experiment can be writen as a deductve statement that includes three components: 1) The inference being tested 2) The experiment that will test the inference 3) The predicted outcome of the experiment If bacteria reproduce through binary fission, and we place a single bacterium into cell culture, then in time the population will increase exponentially. If the Earth has gravity, and we release a massive object in midair, then it will accelerate toward the center of the Earth. 5