Domain Eukarya – Kingdom Plantae* Characteristics: Multicellular, photosynthetic (autotrophic), eukaryotic organisms Origins: Phylum Chlorophyta, Charophyceans (green algae) o Both have: Chlorophyll a, b, and carotene Thylakoid membranes stacked in grana Walls of cellulose Store carbohydrates as starch Cell plate that divides cytoplasm during mitosis Adaptations to land o Roots: obtain water & minerals, anchorage for plant o Stems & Leaves: obtain light & CO2 o Apical meristems:* growth producing regions at tips of roots and stems o Vascular Tissue: transport materials. Xylem* (dead cells): convey water up & Phloem* (living cells): distribute sugars down o Lignin:* imbedded in wall for strength and support o Cuticle: waxy layer to prevent water loss o Stomata: pores on leaf surface, allows for gas exchange o Gametangia:* houses and protects gametes (2n) of a plant o Sporangia:* houses and protects spores (n) of a plant o Seed:* embryo surrounded by protective tissues Embryophytes:* distinguishes plants from algae, dependent embryo attached to the plant o Pollen:* formed from flagellated sperm No longer need water for fertilization Spread by wind, helps disperse over a wider area Life cycle: Alternation of Generations o Multicellular, diploid (2n) & haploid (n) stages are distinct Haploid: produce gametophyte (the gametes) which in turn make gametangia Fertilization of gametes Diploid: produce sporophyte (the spores) which in turn make sporangia ▫ uses meiosis so spores are haploid (may be male, female or both), grow into gametophytes Evolution: moved from sporophyte dependent on gametophyte to gametophyte dependent on sporophyte o Gametophyte can reproduce asexually Plant Major Groupings Bryophytes o Nonvascular: lack lignified cells o Waxy cuticle, flagellated sperm, apical meristems o Bryophyta: Mosses, fuzzy with stalks o Heptophyta: Liverworts, lobes with springs o Anthocerophyta: Hornworts, lobes with horns Seedless Vascular Plants o Psilophyta – whisk “ferns” o Lycophyta – club moss o Sphenophyta – horsetails o Pterophyta – Ferns Microphylls (large leaves) Sporangia (sacs on under side), cluster called sori Flagellated sperm Seed Plants o Seed: embryo packaged with a food supply within a protective covering o Do not require water for fertilization o Gymnosperms:* “Naked Seeds,” seeds are not in specialized chambers Coniferophyta: cone-bearing trees; pines, firs o Angiosperms:* seeds in protective chambers Flowering plants Life Cycles of Plant Groupings Mosses: dominant gametophyte Ferns & most plants: dominant sporophyte Gymnosperms: sporophyte with gametophytes in its cones o Cones with scales make: Megaspore (♀): give rise to ovules Microspores (♂): give rise to pollen o Spore develops into 3 cell gametophyte (egg/pollen) o All happens on the scale of the cone Angiosperms: sporophyte with gametophytes in its flowers o Flower makes megaspores (♀) & microspores (♂) Mitosis makes spores (n) into egg sac and pollen Pollination = fertilization Zygotes develop into seed (2n) o Groups: Monocots* & Dicots* Flower Structure: o Sepal: encloses flower o Petal: Attract pollinators o Stamen: Stalk /Filament o Anther: Pollen grains develop o Carpal: Has the stigma, style & ovary o Stigma: Sticky, traps pollen o Ovary: Seed develops Evolutionary trend in angiosperms o # floral parts reduced o Parts get fused o Symmetry from radial to bilateral o Ovary drops below petals and sepals