Plate Boundaries Divergent Boundaries Occur at mid-ocean ridges Plates move apart (diverge) also called Constructive Boundaries Convergent Boundaries Plates form at trenches also called Destructive Boundaries Severe Earth- quakes form here Strike-slip boundaries Also called Conservative Boundary 2 Plates grind & slip past Horizontally Formed by lateral faults

Movement of Lithospheric Plates

Large Plates Small Plates Movement of Lithospheric Plates

Vary in speed and distance San Francisco, on North Amer. Plate moves southeast about 5 cm. per year If weighted down by continents move only a few millimeters per year Large Plates Small Plates Movement of Lithospheric Plates

Vary in speed and distance San Francisco, on North Amer. Plate moves southeast about 5 cm. per year If weighted down by continents move only a few millimeters per year Large Plates Movement varies in speed and distance Considered small, the Caribbean and Arabian Plates are fairly large Plates that lack landmasses move as much as several centimeters per year Small Plates Movement of Lithospheric Plates

STRIP MINING - completely removing earth’s surface to access minerals & coal CONSTRUCTION – large scale projects (highways) destroying an ecosystem completely WAR – bombs and moving heavy equipment (tanks, etc) over terrain destroys ecosystem ACCIDENTS – events like oil tankers sinking & nuclear power plant “melt-downs” 2 Sudden Catastrophic Impact Quickly & obliviously damaging an ecosystem to the point that it can never be restored How people’s behavior impact the environment in bad ways FERTILIZERS / PESTICIDES kill a variety of animals & plants; leave chemicals POLLUTION / ACID RAIN waste products that kill organisms & break food chains CONSUMING RESOURCES uses up things needed to maintain an ecosystem (i.e., minerals in soil) 1 Slow Subtle Impact Slowly and not obliviously damaging an ecosystem to the point that it can never be restored