Plant Types

"Other woody plants include a group known as the gymnosperms. This group includes pine trees and their relatives plus other non-flowering trees. Less advanced plants include ferns, lycophytes and mosses. Plants made the move from water to land around 500 million years ago. Living on land is significantly different to living on water and plants have had to make serious changes to their body plans in order survive on land. Land plants separated their body plans into roots, stems and leaves. Roots absorb water and nutrients from soil, stems transfer materials between roots and leaves, and leaves produce sugars that provide the plant with energy to survive. Photosynthesis Photosynthesis is a key topic for an introduction to plant biology. It is a process that occurs in plant cells that uses the sun’s energy to produce sugars from carbon dioxide and water. The process is simply a series of chemical reactions, probably the most important chemical reactions of Earth. The green color of plants is caused by a molecule called chlorophyll a. Chlorophyll a has the ability to absorb light energy from the sun. The energy that is absorbed is used to force reactions with water and carbon dioxide. The result of these reactions is the production sugars and oxygen gas. The overall reaction looks like this: energy + water + carbon dioxide → sugar + oxygen Photosynthesis takes carbon dioxide from the atmosphere, converts it into sugar and releases oxygen back into the atmosphere. Over time photosynthesis changed the atmosphere of the Earth by increasing the amount of oxygen in the air. "