From the various places where it originated, agriculture spread gradually to much of the rest of the earth, although for a long time it coexisted with gathering and hunting ways of life. Broadly speaking, this extension of farming occurred in two ways. The first, known as diffusion, refers to the gradual spread of agricultural techniques, and perhaps of the plants and animals themselves, but without the extensive movement of agricultural people. Neighboring groups exchanged ideas and products in a down-the-line pattern of communication. A second process involved the slow colonization or migration of agricultural peoples as growing populations pushed them outward. Often this meant the conquest, absorption, or displacement of the earlier gatherers and hunters, along with the spread of the languages and cultures of the migrating farmers. In many places, both processes took place.