<span>This theory is called punctuated equilibrium. In this theory it is explained that there are very long periods of no change at all to a species, yet there are also bursts of evolutionary change interspersed within the time period. The period of remaining the same throughout time (most of the time) is called stasis, and is present within this theory of punctuated equilibrium.</span>
Plant transport systems move energy from leaves and raw materials from roots to all their parts. The xylem (tissue) moves water and minerals obtained from the soil to all other parts of the plants.
