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. 2. 2. 2.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