Organisms can respond to changes in ecological conditions by adaptively adjusting their traits. This adaptation results from improved fitness, in which adjusted traits lead to the improvement of either or both birth and death processes. Thus, adaptation is naturally linked to population dynamics, although this linkage has received little attention until recently. This symposium focuses on the linkage between adaptation and population dynamics, which has been increasingly reported in regard to theoretical predictions and empirical tests of the predictions. We invite leading researchers of this topic, Dr. William Nelson and Dr. Eelke Jongejans, and by combining with our own talks, we would like to discuss the importance of considering adaption when understanding population dynamics.