定義： The largest scale biogeographic division of the earth's surface based on the historic and evolutionary distribution patterns of plants and animals.
定義： A landform that extends above the surrounding terrain in a limited area. A mountain is generally steeper than a hill, but there is no universally accepted standard definition for the height of a mountain or a hill although a mountain usually has an identifiable summit and a local relief of more than 300m.
定義： the method used by some animals (e.g. bats, dolphins and some whales) to determine the location of something by measuring the time it takes for an echo to return from it. These animals emit sound waves and listen for the echo, calculating the distance to the object from the time lapse between sound emission and the echo returning.
定義： A group of species that exploit the same food resources, and/or use the same feeding or foraging methods. http://en.wikipedia.org/wiki/Guild_(ecology)
