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Chapter 21.1. Plant evolution and Adaptations. Plant Characteristics. Multicellular Autotrophic Eukaryotes Tissues and organs. Green Algae to Plants. Scientists think modern plants may have evolved from Green Algae because of similar characteristics….
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Chapter 21.1 Plant evolution and Adaptations
Plant Characteristics • Multicellular • Autotrophic • Eukaryotes • Tissues and organs
Green Algae to Plants • Scientists think modern plants may have evolved from Green Algae because of similar characteristics…
I Spy…What are the differences between these two Autotrophs? Green Algae Giant Redwood
Similarities of Plants and Algae • Cell walls w/ Cellulose • Same type of Chlorophyll • Food stored as starch • Enzymes in vesicles • Similar genes in rRNA • Cell division w/ cell plate Similar but not the same
What do you think plants needed to adapt to life on land? • A: Bones of course • B: Reproduce by air and land… not water • C: Fed Ex sends weekly care packages of water • D: Wet suit… the air dries me out!
4 Plant Adaptations to Land • Cuticle • Prevents drying out • Barrier to microbes
4 Plant Adaptations to Land • Stomata • Allows for gas exchange
4 Plant Adaptations to Land • Vascular tissue • Allows for movement of nutrients & water • Provides support
4 Plant Adaptations to Land • Seeds • Survive harsh conditions • Food for developing embryo
Alteration of Generations • Gametophyte produces haploid (n) gametes • Sporophyte produces diploid (2n) spores
Kingdom Plantae Nonvascular • Bryophytes- Moss • Antherocerophytes- Hornworts • Hepaticophytes- Liverworts Vascular without seeds • Lycophytes- Club mosses • Spenophytes - Horsetails • Pterophytes- Ferns Vascular with seeds • Cycadophytes- Cycads of sago plants • Gnetophytes- Joint firs • Ginkophytes- Ginkgoes • Coniferophytes- Pines • Anthophytes- Flowering plants
Chapter 21.2 Nonvascular Plants
Nonvascular Plants • Small • Requires water • Found in damp, shady areas
3 Divisions of Non- vascular plants • Bryophyta- Moss • Anthocerophyta- Hornworts • Hepaticophyta- Liverworts • Gametophyte is dominant
Division Bryophyta • One cell thick leaf-like structures • Rhizoids for anchorage • Peat – used for fuel, retain moisture for gardeners Moss
Division Anthocerophyta • One large chloroplast in each cell • May have symbiotic relationship with cyanobacteria Hornwort
Division Hepaticophyta • Unicellular rhizoids • Thallose – fleshy, lobed structures • Leafy – stems with thin leaf-like structures in rows liverwort
Thallose vs LeafyTwo kinds of Liverwort Leafy Thallose
Chapter 21.3 Seedless Vascular Plants
Seedless Vascular Plants • Have Vascular Tissue • Larger than Non-vascular • Better adapted to drier environments • Strobilus – spore bearing structure • Sporophyte is dominant • Division Lycophyta and Pterophyta (Sphenophyta)
Division Lycophyta • Sporophyte is dominant • Have roots, stems, and small, scaly leaf-like structures • Some are epiphytes – lives anchored to another plant or object • Club mosses
Division Pterophyta/Sphenophyta • Horsetails or scouring rushes • Cell walls of silica • Only one genus = Equisetum • Horsetails - Equisetum
Division Pterophyta • Thick underground stem – rhizome (food storage) • Fronds with sporangia underneath (sorus) ferns
Chapter 21.4 Vascular Seed Plants
Vascular Seed plants • Vascular tissue • Cotyledons – food storage for embryo • Seed dispersal • Wind, water, animal • Sporophyte- dominant life cycle • Male gametophyte: Pollen • Female gameophyte: Egg • Produce Seeds • Gymnosperms: “Naked Seed” without fruit. Ex: Pines, fir trees • Angiosperms: Seeds are part of the fruit Ex: Apples, peaches, blackberries
5 Divisions of Seed Plants • Division Cycadophyta • Division Gnetophyta • Division Ginkgophyta • Division Coniferophyta • Division Anthophyta
Division Cycadophyta • Separate male and female plants • Found in tropical and subtropical environments • Cycad
Division Gnetophyta • Live 1500 – 2000 years • 3 genera • Ephedra – bush • Ephedrine medicine • Found in US • Gnetum - trees & climbing vines • Welwitschia – two large leaves
Division Ginkophyta • One living species: • Ginkgo biloba • Fan shaped leaves • Separate male and female trees • Tolerate pollution
Division Coniferophyta • Shrubs and trees • Economically useful • Lumber, paper, turpentine • Male and female cones on same tree • Scalelike leaves with cutin • Evergreen – lose leaves throughout the year
Leaves • Evergreen- Keep some green leaves all year • Deciduous- Lose leaves once a year
Division Anthophyta • Flowering plants
2 kinds of angiosperms • Monocots • One seed leaf • Parallel veins in leaves • Flowers in multiples of 3s • Monocot examples: grasses, orchids, lilies, and palms • Dicots/Eudicots • Two seed leaves • Netted veins in leaves • Flowers in multiples of 4s or 5s • Dicot examples: maples, oaks, sycamores • Eudicot examples: trees, shrubs, flowering plants
Life span of plants • Annual - live for one year • Most are herbaceous (green stems) • Have drought resistant seeds • Examples: corn, wheat, peas, and squash • Biennial - live for two years • Have large storage roots • Produce flowers in the second year • Examples: carrots, beets, and turnips • Perennial – live for many years • Usually flower once a year • Examples: maples and oaks