Concepts are mental categories for facts, objects, events, people, ideas — even skills and competencies — that have a common set of features across multiple situations and contexts. Concepts can range from simple to complex according to how easily they can be defined.
So if concepts are the broad principles or classifications, exemplars then, are the "typical examples" or "excellent models" of that principle. For example, if you are teaching about the concept of fruit, then some good exemplars would be apples, oranges, and bananas. If love is the concept at hand, depending on the type of course you are teaching, some exemplars to use could be the relationship of a mother and daughter, or a group of friends.
Let's consider the 1989 Exxon Valdez oil spill. In a traditional learning model, a teacher might concentrate on the facts surrounding this Alaskan oil spill — when it happened, what caused it, what its effects were. But in a conceptual learning model, the teacher would likely begin by teaching students about the broader concept of environmental sustainability and then introduce the Exxon Valdez oil spill as one specific example that had a negative impact.
In the traditional learning model, students would walk away knowing specific pieces of information, like that the oil spill occurred in Prince William Sound, Alaska in 1989; it involved an oil tanker that spilled millions of gallons of crude oil; and it is considered to be one of the most devastating human-caused environmental disasters.
However, in a conceptual learning model, students would first learn about the concept of environmental sustainability (how it involves decisions and actions that help or harm the natural world and its ability to support human life), and then touch on a few significant examples that fall under this concept, such as: Exxon's Alaskan oil spill and Google's Google Green initiative. In some instances, students might even go on to discuss the parallels or cause and effect relationship between these two examples.