The higher plants and animals reproduce by fusing genetic material from male and female sex organs, usually from different individuals. Animals have the advantage of being mobile: male and female can sense each other’s presence and move toward each other. Plants can’t move, and instead have to depend on mobile go-betweens. The male pollen of most land plants is carried to the female ovule by the wind or by animals. To encourage animals to help out, advanced plants evolved the flower, an organ whose shape, color, and scent are designed to attract a particular assistant, usually an insect. As it flies around and collects nutritious nectar or pollen for food, the insect spreads the pollen from one plant to another.