Plant Diversity II: Evolution of Seed Plants AP Biology Crosby High School

Evolution of Seed Plants Evolution of Seed Plants Gametophyte becomes dependent on Sporophyte Seed: packaged sporophyte embryo w/ food supply in protective coat Seed plants are heterosporous Ovule –Female gametophyte develops inside and produce egg –When fertilized by sperm zygote becomes sporophyte and creates seed

Gymnosperms Ginkgophyta Phylum Cycadophyta: resemble palms Phyum Gnetophyta: –Welwitschia: giant strap like leaves –Gnetum: tropical trees and vines –Ephedra: (Mormon tea) shrub in American desert Phylum Coniferophyta Phylum Coniferophyta

Angiosperms All are phylum Anthophyta Monocot, dicot, or eudicot Tracheid, vessel elements, fiber cells Tracheid, vessel elements, fiber cells Flower: angiosperm reproductive structure –4 circles of modified leaves 4 circles of modified leaves4 circles of modified leavesSepalsPetalsStamensCarpel

Fruit Mature ovary Types: –Simple fruit –Aggregate fruit –Multiple fruit Dispersal: –Burrs –Edible fruit

Angiosperm Life Cycle Angiosperm Life Cycle Some self-pollinate, others ensure cross- pollination One sperm fuses w/ egg, the other with 2 central nuclei After Double Fertilization –Zygote develops into sporophyte –Triploid nucleus creates endosperm

Life Cycle Life Cycle

Xylem Cells

Parts of a Flower

Conifer Life Cycle Conifer Life Cycle

Gametophyte to Sporophyte