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.
EYE STRUCTURE AND FUNCTION. E ye is like a camera. The external object is seen like the camera takes the picture of any object. Light enters the eye through a small hole called the pupil and is focused on the retina, which is like a camera film.Eye also has a focusing lens, which focuses images from different distances on the retina. The colored ring of the eye, the iris, controls the amount of light entering the eye.It closes when light is bright and opens when light is dim. A tough white sheet called sclera covers the outside of the eye. Front of this sheet (sclera) is transparent in order to allow the light to enter the eye, the cornea.he colored ring of the eye, the iris, controls the amount of light entering the eye. It closes when light is bright and opens when light is dim. A tough white sheet called sclera covers the outside of the eye. Front of this sheet (sclera) is transparent in order to allow the light to enter the eye, the cornea.