The five core concepts of biology

Biology stretches from single atoms to the whole biosphere, yet a few big ideas apply at every level. Vision and Change, a national effort by biology educators to improve how college biology is taught, named five of these ideas as the core concepts of biology.

The five concepts at a glance

Exams often describe an example and ask which concept it illustrates, so learn all five by name. Their first letters, in order, give you a reminder:

Evolution and structure

Evolution is change in a population over many generations, in ways that offspring inherit. Its main drivers are changes in an organism’s inherited instructions (mutation), the spread of traits that help organisms survive and reproduce (natural selection), and the movement of genes between organisms (genetic exchange).

As populations evolve, they become better suited to the environments they live in. A trait that helps an organism survive and reproduce in its environment is an adaptation. The anteater’s long snout is one: the fossil record shows that modern anteaters evolved from populations with shorter snouts.

Biologists often say that structure determines function, and the rule holds at every scale, from tiny molecules to whole body parts. Bird feet make the point. A duck’s webbed feet push against the water like paddles. A chicken’s separate, unwebbed toes are better for gripping a perch, holding food, and running on land.

Information, energy, and matter

An organism’s inherited instructions are written in DNA (deoxyribonucleic acid), a molecule that acts like a blueprint: it guides how the organism is put together, how it develops, and how it works. When organisms reproduce, each offspring receives a copy of the blueprint. Because DNA passes from parents to offspring this way, it is heritable, which is why offspring tend to resemble their parents.

Every organism also takes in energy and matter (the physical material everything is made of) from its environment. It uses them to build the molecules it needs and to keep its cells and body organized. These chemical changes obey the laws of thermodynamics, the rules of physics that govern how energy is transferred and converted.

Plants show the idea clearly through photosynthesis: they capture light energy and use it to turn carbon dioxide and water into carbohydrates (sugars). The light is the energy. The carbon dioxide, the water, and the sugars built from them are the matter.

Systems and emergent properties

Living things are systems, sets of connected parts that constantly interact. As an organism’s parts act on one another, and on the world around them, they can give rise to structures and abilities that no single part has by itself. These are emergent properties.

Your ability to see is one. No single cell in your eye can see; sight emerges from many types of cells arranged to sense light and send signals to your brain.

The study of how new properties of life emerge from interactions among its parts is systems biology.

Check yourselfA hummingbird drinks nectar and uses its sugar both to power its wings and as raw material for building its body. Which core concept does this illustrate?

Pathways and transformations of energy and matter. The bird takes in energy and matter from its environment and chemically transforms them to fuel its activity and build its tissues.

Check yourselfWhy is vision described as an emergent property?

It exists only because many types of eye cells work together with the brain. No individual cell can see on its own.