evolution of plants chapter ch 21 pp. 559-562 pp. 564 chap 22: pp. 577-579; pp. 581; 584-587;...
TRANSCRIPT
Evolution of PlantsChapter Ch 21 pp. 559-562
pp. 564
Chap 22: pp. 577-579; pp. 581; 584-587; 588-590; 594-597.
Characteristics Of all Plants
1. Cell walls of cellulose
2. Cuticle: Waxy, waterproof coating; avoid drying up.
4. Reproduce by Spores & seeds
5. Alternation of Generations
I. Evolution of Plants
Evolved from Algae-chlorophyta
Adaptations to Dry Land:
Overcame 3 Challenges:Overcame 3 Challenges:1. Avoid Drying Out1. Avoid Drying Out2. Obtain Minerals (nutrients) and 2. Obtain Minerals (nutrients) and
Water from Rocky SurfacesWater from Rocky Surfaces3. Reproduce on Land3. Reproduce on Land
Challenge #1Cuticle
Waxy, waterproof coating on leaves & stems
avoid drying up
Challenge #2: Distribute water & Nutrients.
Most have Vascular Tissue These are called Vascular Plants
Vessels transport Water and NutrientsEnables Plants to Grow LARGE
Challenge #2 --More
Non-vascular plantsMossNo Vascular tissue
Live in moist environmentsTransport water & nutrients by Osmosis & diffusion
Challenge #3-Reproduce On Land---Spores and Seeds
Reproductive StructuresReproductive Structures Resist Resist Drying.Drying. 1.Spores: Tiny; Wind Carried
Produced by All Nonvascular Plants and some vascular Plants (the ferns)
2. Seeds: Produced by Vascular Plants: Plant embryo surrounded by protective coat.
Alternation of Generations:
• Two Forms during plant life cycle:
• Haploid Gametophyte Stage alternates with a Diploid
Sporophyte Stage
II. Types of Plants1.Nonvascular-Bryophytes (mosses)
2.VascularA)Spore-Bearing---FernsB) Seed bearing
1) Gymnosperms-”Naked” Seeds2) Angiosperms-Seeds in Fruits
Nonvascular PlantsMosses (most widespread)
Liverworts, Hornworts
Nonvascular Plants-Characteristics
1. The First Successful Land Plants
2. Small (most under 1 inch tall)
3. No vascular Tissues.
More Non Vascular Plant Characteristics
4. Need Lots of Water:
Habitat: moist; swampy; shorelinesDiffusion & Osmosis: Obtain water &
Nutrients For reproduction-sperm swim to egg.
5. Rhizoids-Primitive Root-Anchorlike & absorptive6.Cuticle on upper surface only
7. Gametophyte is dominant –green, leafy
Reproduction in Mosses1.Gametes form at tips of Green, Leafy Gametophyte (what we usually see).
2. Sperm swim to egg (need film of water).
(fertilization zygote)
3.Moss Sporophyte grows from this Zygote
(bare stalk with a spore capsule on top; here haploid spores form; nutrients obtained from the gametophyte it is growing on top of)
4. Capsule opens; wind carries spores.
5. Spores grow into new Gametophyte.
III. Evolution of Vascular Plants—Ferns, shrubs, trees
Vascular Tissuea) Xylem: water and minerals from roots
upb) Phloem: sugar from leaves to all tissuesEarliest Used Spores Instead of Seeds (Ferns)Sporophyte is Dominant
Ferns: Seedless Vascular Plant Reproduce by spores—no seeds—
Continued
3. Gametophyte produces gametes.
4. Water carries sperm to egg, they fuse (Fertilization) to form diploid Sporophyte Form.
Cycle continues.
Vascular Plants:Seed Plants Adaptation to dry
environments.A)Vascular tissue-carry
water & nutrientsB)Reproduce without
water; PollenC) Seeds-protect
embryo
2 Divisions: Gymnosperms (cones) & Angiosperms (flowers & fruits)
SEEDS-Survive unfavorable Conditions
1.House the plant Embryo.
2. Hard outer Seed Coat-protects embryo.
3. Contain stored nutrients.Endosperm: food for embryoCotyledon- surrounds embryo of flowering
plant-first leaves .Cotyledon Stores food or helps absorb food stored elsewhere.
…More on Seeds4. Help carry plants distance from parents:wind & animalsHooks, feathery or winglike structures
Seeds5. May remain dormant.
6. Upon favorable conditions, seed Germinates (cracks open & starts to grow) into a Seedling.
Seed Plants-2 types1.GymnospermsHave ____________
2.Angiosperms: have___
Types of Seed Plants #1. Gymnosperms- “Naked
Seeds”
Seeds Form in Cones.
Vascular Plants With Seeds-
#2. Angiosperms1. Flowers and Fruits
2.Majority of Vascular plants.
Seeds formed in flowers and enclosed in Fruits.
Angiosperms-Flowers:Help ensure pollination:
Colors, shapes, fragranceAttract particular insects, birds, etc.
Fruit Protects seeds
Helps disperse seeds
ACTIVITYVascular or Non vascular Plant?Spore or Seed Bearing?Dominant Stage/Generation?Label the: GametophyteSporophyte
Describe the process of reproduction in this plant?
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