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.
This highly flexible, yet heavy, body part is integral to the gangly animal's movement. Watch a giraffe and you'll notice that the neck moves back and forth with its stride. That's because the weight and motion of the neck guides the giraffe's center of gravity [source: Dagg and Foster ]. The animal also tosses its neck to and fro to help it rise to a standing position on its spindly legs.