| 
			 | 
				
					| The Invasion of Land 1 |  
					| Lecture 20 4/13/98
 |  
 
				
					| |  | This week, we will discuss of the invasion of land by life. We will start with the plants. | 
 |  | We will then continue the discussion by focusing on the invertebrate and vertebrate groups that followed the plants. | 
 |  | The invasion of land by plants is one of the major events in the history of Life | 
 |  | Opened new environments for animals to utilize. | 
 |  | Changed the nature of physical and chemical processes on earth. | 
 |  | Living on land required new strategies for survival. | 
 | Requirements for living on land | 
 |  | Rhynie Chert beds in Scotland | 
 |  | Improvements on Rhyniophyte design | 
 |  | development of secondary xylem (wood) | 
 |  | development of true roots | 
 |  | ancestors of modern club mosses | 
 |  | male and female gametophytes form cones | 
 | Results of the plant invasion | 
 |  | Increase size of Continents | 
 |  | Changes in atmospheric chemistry | 
 |  | Opening new environments for animals | 
 
						 |  |