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

The Process of Science in Biology

Learning Objectives

• 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.

• Understand 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: Organisms are capable of reproduction, producing new individuals either sexually or asexually.

• 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 maintain internal order and support growth.

• Evolution: Populations of organisms undergo continual evolution over generations, leading to diversity and adaptation.

Example: A bacterium is a single-celled organism that can reproduce, uses energy from nutrients, responds to environmental changes, and evolves over time.

How Do We Know All This?

The Scientific Process

Our understanding of life is built on the scientific process, which is a systematic approach to investigating natural phenomena.

• Observation: Gathering information about the natural world.

• Hypothesis Formation: Developing testable explanations (hypotheses) based on observations.

• Experimentation: Designing and conducting experiments to test hypotheses.

• Data Gathering and Analysis: Collecting and interpreting data to draw conclusions.

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

Some of the greatest unifying theories in science include:

• Cell Theory: All living things are composed of cells.

• Chromosome Theory of Inheritance: Genetic information is carried on chromosomes.

• Theory of Evolution: Species change over time through natural selection and other mechanisms.

These theories are supported by a wide body of evidence from multiple scientific disciplines.

The Process of Science – What Is It?

Definitions and Nature of Science

• Science is a system of knowledge covering general truths or the operation of general laws, especially as obtained and tested through the scientific method (Merriam-Webster Dictionary).

• It is a systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the universe (Oxford University Press).

Key Terms:

• Scientific Method: The process by which scientists investigate questions, involving observation, hypothesis formation, experimentation, and analysis.

• Theory: In science, a theory is a well-substantiated explanation of some aspect of the natural world, based on a body of evidence and repeatedly tested and confirmed through observation and experimentation.

• Hypothesis: A testable statement that explains a set of observations and can be supported or refuted by experimentation.

Example: The cell theory was developed after repeated observations and experiments showed that all living things are made of cells.

Additional info: The images of scientific journals (e.g., Science, Nature, PNAS, Evolution) illustrate the ongoing process of scientific discovery and peer review in biology.