General Biology Notes

Chapter 1: What is Science?



1. Science is a way of knowing: 


Science is an ongoing body of knowledge that is always changing.  Science is based on asking questions, making observations and inferences, and testing hypotheses.  (standard NoS 2)

·         Science is a process, not a thing.

·         Science deals only with the natural world, not with the supernatural.

·         Scientists collect and organize information while trying to find patterns and make connections.

·         Scientists propose explanations that can be tested based on evidence, not belief.


2. The goals of science:

·         To provide natural explanations for events in the natural world.

·         To use those explanations understand patterns and to make useful predictions.


3. Scientific understanding is always changing.


·         Some things you learn in this biology class will change or be revised because of new discoveries and experimentations.  (standard NoS 9)

·         This does NOT mean that science has failed.  It means that science continues to succeed in advancing understanding.

·         Good scientists are constantly questioning new and old theories and hypotheses.

·         Scientists must be curious, skeptic, open-minded and creative and consider new hypotheses if new data is presented.

·          Science should never be based on personal opinion or bias.  Bias is a particular preference of point of view that is personal, rather than scientific. Ex: If you like or dislike how a BMW drives or what breed of dog is the prettiest and best to own.

·          Using science involves understanding its context in society and its limitations. Science both influences society and is influenced by society Ex: How much of the information in you genes should be kept private? How should communities produce electricity? How should chemical wastes be disposed of? (standard NoS 11)

·         New technology and techniques enable scientists in other fields to ask new questions or to gather data in new ways.



Ex: The engineering of the space shuttle and satellites have allowed us to explore space.


image of the Hubble Space Telescope


Ex: The microscope has allowed us to explore cells and small organisms.



Theories and Laws  Modified from Jerry Wilson’s outline


People often misinterpret the language used by scientists.  Therefore, they sometimes draw the wrong conclusions as to what the scientific terms mean.


To the everyday person, if something is said to be “just a theory”, it usually means that it is a mere guess, or is unproved.  It might even lack credibility. 


But in scientific terms, a theory implies that something has been proven or accepted by multiple scientific experiments and is generally accepted as being true.


A.    Hypothesis: This is a scientific explanation for a set of observations that can be tested, but which has not yet been proved.  Most hypotheses can be supported or refuted by experimentation or continued observation.

·      The biggest difference between a hypothesis and a theory is that a theory has been proven or accepted and a hypothesis has not yet been proven or accepted.  


B.     Scientific LawThis is a statement of fact meant to explain, in concise terms, an action or set of actions.  It is generally accepted to be true and universal, and can sometimes be expressed in terms of a single mathematical equation.  Scientific laws are similar to mathematical postulates.  They don’t really need any complex external proofs; they are accepted at face value based upon the fact that they have always been observed to be true.

·      Examples of scientific laws or laws of nature:  Newton’s Law of Gravity, the Law of Thermodynamics, Newton’s Law of Motion, the various Gas Laws.


C.    Theory: A theory is more like a scientific law than a hypothesis.  A theory is a well-tested explanation that unifies a broad range of observations and hypotheses and that enables scientists to make accurate predictions about new situations. One scientist cannot create a theory; he/she can only create a hypothesis.  (Standard NoS 8)

·      In general, the scientific community as a whole accepts both a scientific theory and a scientific law to be true.  Both are used to make predictions of events.  Both are used to advance technology.

·      The biggest difference between a law and a theory is that a theory is much more complex.  A law governs a single action, whereas a theory explains a whole series of related phenomena. 

·      Examples of Scientific theories: the theory of evolution, the theory of relativity, the theory of natural selection, the cell theory, the theory of plate tectonics, the atomic theory, the theory of planetary motion. 

Analogy: (standard NoS 6)

A scientific law is like a slingshot.  A slingshot has one moving part, the rubber band.  If you put a rock in it and draw it back, the rock will fly out at a predictable speed, depending upon the distance the band is drawn back.


An automobile has many moving parts, all parts working in unison to perform the task of transporting someone from one point to another point.  An automobile is a complex piece of machinery.  Sometimes, improvements are made to one or more component.  A new set of brake pads that are composed of a better alloy that can withstand more friction and heat for example, might replace the existing set.  But the function of the automobile as a whole remains the same. 


A theory is therefore more like an automobile because parts of it can be changed or improved given more evidence or better parts without changing the truth of the theory as a whole.  Theories are often “tweaked”, but they are rarely, if ever, entirely replaced.