Chap. 28 : Evolution of Plants

I. Kinds of :  1. Nonvascular – does not have vascular tissue (veins), roots, stems, or leaves.  --- will always remain small  Ex. Bryophytes –moss,liverworts,hornworts

-- most primitive type of plants -- usually first plants formed on new land called pioneer species -- instead of roots they have rhizoids (thin, hair- like) 2. Vascular – does have vascular tissue, roots, stems, and leaves A. Seedless – ferns (reproduce by spores)

B. Seed 1. Gymnosperms – seeds not enclosed  -- most are evergreen, have  cones, and needles. Male cones female cones

2. Angiosperms – seeds enclosed in fruits and flowers. Ex. Most trees except Ginkgo  Angiosperms are the most successful because seeds are protected, trees mature quicker to reproduce.  ---- Class Monocot – one cotyledon (seed leaf). Ex. Corn, bamboo, pineapple  ---- Class Dicot – two cotyledons. Ex. Most forest trees

II. Alternation of Generations -- life cycle of plants that involve 2 phases: sporophyte and gametophyte. 1. Sporophyte – 2x # of chromosomes – makes spores Gametopyte- one x # of chromosomes.---- in in nonvascular plants the gametophyte is the dominant generation (seen most often) --- in vascular plants the sporophyte is the dominant phase. Ex. Oak tree is sporophyte