Weathering is the breakdown of rock in place and includes four main types: freeze-thaw weathering, onion-skin weathering through exfoliation, biological weathering by plant roots, and chemical weathering as water dissolves rock. Weathering breaks up and weakens rock while erosion wears away and removes loosened material, with rivers, ice, sea, and wind causing significant erosion; erosion works together with transportation and deposition to shape landscapes and form environments like coasts.