Scientific models and core skills

Most diagrams in a biology textbook aren’t photographs of real things. They’re models, simplified depictions of how biologists think something is built or works, and learning to read and build them is one of the skills a biology course sets out to teach.

Six core skills

Along with the five core concepts, Vision and Change identified six core skills, also called core competencies, that biology students should develop:

• Applying the process of science
• Using quantitative reasoning (working with numbers and data)
• Using models and simulation
• Tapping into the interdisciplinary nature of science (drawing on chemistry, physics, math, and other fields)
• Communicating and collaborating with professionals in other disciplines
• Understanding the relationship between science and society

You’ve already seen the first two at work. The maple tree experiment followed the process of science, from observation to conclusion, and judging its results with statistics took quantitative reasoning.

What models are and why they help

Biologists often capture a real-world structure or process in a simplified form, such as a diagram, an equation, or a physical object. That representation is a scientific model: a conceptual, mathematical, or physical depiction of a real-world phenomenon.

Every model is a simplification. It keeps the parts that matter for the question at hand and leaves out the rest. Living things are so complex and varied that almost every model falls short of reality in some way. A biological model is also a testable idea, usually built from observations and experiments.

Models help biologists in four main ways:

• They make ideas easy to communicate. A model of the human heart, for example, shows how its parts work together to pump blood.
• They serve as working hypotheses, helping researchers picture or explain a process and plan further experiments. Models that don’t fit the data are rejected or refined.
• They make predictions that experiments can support or refute.
• They can grow into conceptual frameworks, big ideas that organize a whole field.

Five kinds of models

Some models combine types. A model of how DNA is copied, for instance, is structural, mechanistic, and temporal at once.

Learning by evaluating models or building your own is called model-based learning. It deepens your understanding of scientific concepts and sharpens your critical thinking.

Check yourselfAn ecologist writes an equation that predicts how many rabbits a meadow will hold five years from now. What type of model is this?

A mathematical model. It describes a process with mathematical symbols in an equation, and it can be used to make predictions.

Check yourselfA diagram shows populations nested inside communities, and communities nested inside ecosystems. What type of model is it, and why?

A hierarchical model, because it arranges its parts in nested levels, each contained within the one above it.