Gametophyte

Plant Diversity I: How Plants Colonized Land Chapter 29 Overview: The Greening of Earth For more than the first 3 billion years of Earth?s history, the terrestrial surface was lifeless Cyanobacteria likely existed on land 1.2 billion years ago Around 500 million years ago, small plants, fungi, and animals emerged on land ? 2011 Pearson Education, Inc. Since colonizing land, plants have diversified into roughly 290,000 living species Land plants are defined as having terrestrial ancestors, even though some are now aquatic Land plants do not include photosynthetic protists (algae) Plants supply oxygen and are the ultimate source of most food eaten by land animals ? 2011 Pearson Education, Inc. Figure 29.1 1 ?m Concept 29.1: Land plants evolved from green algae