When did the first plants on earth begin to grow on land and what were they called? July 18, 2014 by Karen Hill | Filed Under: Earth The first plants to begin growing on land were bacteria, or microscopic plants, in the Ordovician period, 505 to 438 million years ago. Lichens, mosses, and liverworts followed the bacteria onto land. Before the Ordovician period ended, a varied plant population, including ferns and trees, extended all over Earthâs land masses. Related
The iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. Eye color is the color of the iris, which can be green, blue, or brown.
The color of the iris gives the eye its color. In optical terms, the pupil is the eye's aperture and the iris is the diaphragm that serves as the aperture stop.