Population ecology is the study of these and other questions about what factors affect population and how and why a population changes over time. Population ecology has its deepest historic roots, and its richest development, in the study of population growth, regulation, and dynamics, or demography.
While running, the neck of a giraffe moves backward and forward to keep the animal balanced. Giraffes have a top speed of about 56 kilometres per hour (35 miles per hour), however, because its legs are so long a galloping giraffe does not appear to be going very fast.
Dynamic stretching involves movements (such as wide arm circles) that more closely resemble what the body does during sports activities, but without the bouncing often involved in static stretching.