The gradual process of marine plants that evolved into land plants. This occurence spanned many groups of plants as they acquired increasing structural complexity while trying to adapt to land. This process shows the many problems of going from a marine to terrestrial environment such as Gravity, Air, Wind, Water Uptake, Anchorage, and Reproduction.
First Land Plants
Amphibian in nature, these plants still relied on free water and a moist environment. Characteristics: non-vascular, seedless gametophyte, PS bodies, small size, no roots, stems, or leaves (or flowers). Types: Bryophytes - mosses (bryophyta), Liverworts (hepaticophyta and hepatophyta), and Horn Warts (anthecerophyta)
Vase shaped structure containing the egg cell.
Swimming sperm cells.
Lower Vascular Plants
2nd step in terrestrialization. Lycophytes and Pleridophytes. Evolved conducting system to move H2O and sugars. (Xylem)
Movement of H2O in cells is inversely proportional to the distance. EX: 1 second for H2O to diffuse through 1 cell. 1 year for H2O to diffuse through 500 cells (one foot).
First Organ to Evolve in Terrestrialization
Stems allowed for SA/VOL conservation because it allows the plant to grow horizontally so it can branch out.
2 Branches at each split or node.
When both the male and female gametophytes are the same size.
2 sizes - microspores/microgametophyt = sperm and megaspores/megagametophyte = egg. This duality allowed for greater specialization of the different gametes & gametophytes.