Notoedric mange, a disease caused by mites, becomes epidemic in western gray squirrel populations and is a major source of mortality. Other species of eastern gray squirrels, fox squirrels, California ground squirrels and wild turkeys are expanding and compete with the western gray.
Principles of Design. Unity/Harmony. Definition of Unity: occurs when all of the elements of a piece combine to make a balanced, harmonious, complete whole. Unity is another of those hard-to-describe art terms but, when it's present, your eye and brain are pleased to see it. Definition of Harmony: brings together a composition with similar units.
By unity of type is meant that fundamental agreement in structure, which we see in organic beings of the same class, and which is quite independent of their habits of life. On my theory, unity of type is explained by unity of descent.