Providers of the Planet The Plant Kingdom Providers of the Planet

Why study/preserve plants? So you can: Breathe  plants process CO2 and give off O2 Eat  all food was made because of plants Use energy  Ancient plants formed coal Have raw materials  cotton to lumber Create new medicines/drugs  non-stop research Save money  on home heating and cooling Impress your girlfriend  they like roses  Have nice landscaping  impress neighbors and increase property values! Slow/stop/reverse global warming  process CO2 Be a good steward of the environment!

Challenges of Life on Land Obtaining resources from two places at once Staying “afloat” in air Maintaining moisture Reproducing

Obtaining Resources From Two Places at Once Resources required for photosynthetic plant are found in air and soil Light and CO2 found above ground Water and minerals found below ground. Adaptation – Vascular System

Staying “Afloat” in Air Air does not provide support to plants Plants stand upright because they contain strong and rigid tissue Adaptation – Lignin: chemical that hardens the plants’cell walls Lignin is the main component of wood

Maintaining Moisture Most plants are exposed to dry air, but cellular processes must still take place in an aqueous environment Adaptation – Cuticle: waxy surface that coats the leaves, helping the plant body retain water Adaptation – Stomata: microscopic pores that allow for gas exchange Cuticle slows down the gas exchange of CO2 and O2 between the surrounding air and the inside of leaves

Reproducing on Land Plants must keep their gametes and developing offspring from drying out in the air Plants must have some means for dispersal other than water current Adaptation – Production of gametes in protective cells sperm travel within pollen embryos are eventually dispersed as seeds, enclosed in protective coats

Adaptations: 1. Some plants developed Vascular Tissues Vascular tissues - system of tubes to move water and nutrients (plants have leaves, stems, and roots

Adaptations: 2. Cuticle - surface of plant covered with this waxy layer to reduce water loss 3. Spores - more effective way to reproduce

Continuing adaptations Thorns, poison, bad taste, etc.  ward off predators Woody tissue  support Seeds  protected/distributed in fruit

Bryophytes Non–vascular plants Examples Small size mosses Require H2O for sexual reproduction Examples mosses liverworts hornworts Water and nutrients transported by osmosis and diffusion – can only move material short distances Larger gametophyte (dominant generation)

Teraphytes Seedless Vascular Plants Water needed for fertilization Drought–resistant spores Examples Ferns club Mosses horsetails Vascular system allows them to grow larger Larger Sporophyte

Gymnosperms Gymnosperms (+ seeds) Seeds Wind pollination Gymnos = naked Sperma = seed Wind pollination Diploid generation Examples conifers cycads ginkgo gnetophytes Seeds protect plant, provide nutrients, permit them to survive long periods of unfavorable conditions, allow for dispersal far from parent plant. Greatly Reduced Gametophytes Male gametophyte = pollen Female gametophyte = form with the seed

Gymnosperms The tallest living plants are the redwoods of California and Oregon The oldest trees in the world are the bristlecone pines. Some are ~5,000 years old! Seeds protect plant, provide nutrients, permit them to survive long periods of unfavorable conditions, allow for dispersal far from parent plant. Greatly Reduced Gametophytes Male gametophyte = pollen Female gametophyte = form with the seed

Angiosperms Flowers Fruits Endosperm Examples roses apple trees Angeion = case Sperma = seed Endosperm Examples roses apple trees corn tomatoes Most recent group of plants to evolve. Most successful Flowers promote pollination and fertilization. Bright colors and strong scents attract pollinators Fruits main function is to promote seed dispersal

Evolution of Plants Bryophyte Seedless Seeded Pterophyte Gymnosperm Angiosperm Plant Kingdom Non-vascular Plants Tracheophyte

Other ways to classify plants Size – taller plants need vascular tissue Woodiness Woody plants (trees, shrubs, vines) Herbaceous plants (flowers, grasses) Reproduction (seeds or no seeds, fruit vs. cones) Life span Annual  one year life span (petunia, impatiens) Biennial  two year life span (hollyhock) Perennial  live many years (trees, lilies, roses)