The Process of Science in Biology: Characteristics of Life and Scientific Inquiry

Process of Science in Biology

Learning Objectives

The study of biology begins with understanding the nature of life and the scientific processes used to investigate living systems. The following objectives guide foundational learning in General Biology:

• Describe the fundamental characteristics of life.

• Walk through the key steps of the scientific method.

• Develop hypotheses based on observations.

• Understand the scientific meaning and rigor of a theory.

• Recognize that correlation is not causation.

What Does It Mean to Say That Something Is Alive?

Characteristics (Traits) of Living Organisms

Biologists define life by a set of fundamental characteristics shared by all living organisms. These traits distinguish living things from non-living matter.

• Cellular Organization: Individual organisms are made up of one or more membrane-bound cells. The cell is the basic unit of life.

• Reproduction: Living organisms are capable of reproduction, producing offspring that inherit genetic material from their parents.

• Information Processing: Organisms process hereditary information encoded in genes and respond to information from their environment.

• Energy and Element Utilization: Organisms acquire, modify, and use energy and elements to sustain life processes.

• Evolution: Populations of organisms undergo continual evolution, adapting to their environment over generations.

Example: Humans, bacteria, and plants all share these traits, though they may express them differently (e.g., sexual vs. asexual reproduction).

How Do We Know All This?

The Scientific Process

Our understanding of life is built on the scientific process, a systematic approach to inquiry that relies on evidence and logical reasoning.

• Observation: Careful examination of natural phenomena.

• Hypothesis Formation: Developing testable statements to explain observations.

• Experimentation: Designing and conducting experiments to test hypotheses.

• Data Gathering and Analysis: Collecting and interpreting results.

• Continuous Refinement: Scientific knowledge is updated as new evidence emerges.

Example: The cell theory was developed after repeated observations with microscopes showed that all living things are composed of cells.

Unifying Theories in Biology

Major Scientific Theories

Biology is unified by several major theories, each supported by extensive evidence:

• Cell Theory: All living organisms are composed of cells, and all cells arise from pre-existing cells.

• Chromosome Theory of Inheritance: Genetic information is carried on chromosomes and passed from parent to offspring.

• Theory of Evolution: Species change over time through processes such as natural selection.

Example: The theory of evolution explains the diversity of life and is supported by fossil records, genetic data, and observed adaptations.

Process of Science – What Is It?

Definitions of Science

Science is defined as both a body of knowledge and a method for acquiring that knowledge.

• System of Knowledge: Science covers general truths or the operation of general laws, especially as obtained and tested through the scientific method (Merriam-Webster Dictionary).

• Systematic Enterprise: Science builds and organizes knowledge in the form of testable explanations and predictions about the universe (Oxford University Press).

Example: Scientific journals such as Science, Nature, PNAS, and Evolution publish peer-reviewed research that advances our understanding of biology.

The Scientific Method

Steps of the Scientific Method

The scientific method is a structured approach to investigating questions about the natural world.

1. Observation: Noticing and describing phenomena.

2. Question: Asking why or how something occurs.

3. Hypothesis: Proposing a testable explanation.

4. Experiment: Designing and performing tests to evaluate the hypothesis.

5. Analysis: Interpreting data to draw conclusions.

6. Conclusion: Accepting, rejecting, or refining the hypothesis based on evidence.

Example: The cell theory was tested by experiments that showed cells only arise from pre-existing cells, not spontaneously.

Scientific Theory vs. Hypothesis

Definitions and Differences

• Hypothesis: A tentative, testable statement about the natural world.

• Theory: A well-substantiated explanation of some aspect of the natural world, based on a body of evidence and repeatedly tested hypotheses.

Example: The theory of evolution is supported by many hypotheses and experiments, while a hypothesis might propose a specific mechanism for adaptation.

Correlation vs. Causation

Understanding Relationships in Science

It is important to distinguish between correlation (when two variables change together) and causation (when one variable directly affects another).

• Correlation: Indicates a relationship between variables, but does not prove one causes the other.

• Causation: Demonstrates that changes in one variable directly result in changes in another.

Example: Increased sales of organic food and autism prevalence may be correlated, but this does not mean one causes the other.

Sources of Scientific Information

Types of Scientific Literature

• Primary Literature: Peer-reviewed manuscripts presenting original research, including sections such as Abstract, Introduction, Methods, Results, Discussion, and Acknowledgements.

• Secondary Literature: Textbooks and review articles that summarize scientific consensus across multiple studies.

• Popular Outlets: Magazines and websites that communicate scientific findings to a broader audience, ideally referencing original research for credibility.

Example: A research paper in Nature may be summarized in a textbook or discussed in a science news article.