Evolution of Plants Chapter Ch 21 pp pp. 564 Chap 22: pp ; pp. 581; ; ;

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 Out 1. Avoid Drying Out 2. Obtain Minerals (nutrients) and Water from Rocky Surfaces 2. Obtain Minerals (nutrients) and Water from Rocky Surfaces 3. Reproduce on Land 3. Reproduce on Land

Challenge #1 Cuticle 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 Nutrients Enables Plants to Grow LARGE

Challenge #2 --More Non-vascular plants Moss No Vascular tissue Live in moist environments Transport water & nutrients by Osmosis & diffusion

Challenge #3-Reproduce On Land---Spores and Seeds Reproductive Structures Resist Drying. Reproductive Structures Resist 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

Alternation of Generations 1. Gametophyte, Haploid form of the plant, 2. Produces Gametes. 3. Fertilization occurs when 2 gametes fuse. Zygote forms. 4. Diploid Sporophyte Forms from zygote. Sporophyte cells undergo (5) Meiosis, 6. Spores produced. Each spore develops into a haploid Gametophyte. —cycle continues…

Alternation of Generations Gametophyte Spores (haploid) Gametes Meiosis Fertilization (diploid) Sporophyte

Dominant Stage: What we see the most. The most visible;Much larger; More Complex Usually the Sporophyte is the DOMINANT Stage. For Example: A spruce tree is a sporophyte.

II. Types of Plants 1.Nonvascular-Bryophytes (mosses) 2.Vascular A)Spore-Bearing---Ferns B) Seed bearing 1) Gymnosperms-”Naked” Seeds 2) Angiosperms-Seeds in Fruits

Nonvascular Plants Mosses (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; shorelines Diffusion & Osmosis: Obtain water & Nutrients For reproduction-sperm swim to egg. 5. Rhizoids- Primitive Root-Anchorlike & absorptive 6.Cuticle on upper surface only 7. Gametophyte is dominant –green, leafy

Moss Activity: Use textbook, p. 282 to draw, color, label; summary questions Draw and color appropriately the following: A patch of moss Include the Sporophytes and Gametophytes (colored appropriately). Questions to Answer Size-approx. Vascular or Nonvascular? Dominant Stage?

Reproduction in Mosses 1.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.

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III. Evolution of Vascular Plants—Ferns, shrubs, trees Vascular Tissue a) Xylem: water and minerals from roots up b) Phloem: sugar from leaves to all tissues Earliest 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.

Fig. 22.9, p. 347 The sporophyte (still attached to the gametophyte) grows, develops. zygote fertilization Diploid Stage Haploid Stage egg sperm egg- producing structure sperm- producing structure mature gametophyte (underside) Spores develop. meiosis spores (one of the spore-producing structures) Spores are released from spore- producing structures. A pore germinates, grows into a gametophyte. rhizome

Vascular Plants:Seed Plants Adaptation to dry environments. A)Vascular tissue-carry water & nutrients B)Reproduce without water; Pollen C) 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 embryo Cotyledon- surrounds embryo of flowering plant-first leaves. Cotyledon Stores food or helps absorb food stored elsewhere.

…More on Seeds 4. Help carry plants distance from parents: wind & animals Hooks, feathery or winglike structures

Seeds 5. May remain dormant. 6. Upon favorable conditions, seed Germinates (cracks open & starts to grow) into a Seedling.

Seed Plants-2 types 1.Gymnosperms Have ____________ 2.Angiosperms: have___

Types of Seed Plants #1. Gymnosperms- “Naked Seeds” Seeds Form in Cones.

Conifers areMost familiar types. Produce 2 types of cones: 1. Female -seed cones 2. Male LOTS OF Pollen!!!!

Gymnosperms Are Wind pollinated Pollination:

Vascular Plants With Seeds- #2. Angiosperms 1. Flowers and Fruits 2.Majority of Vascular plants. Seeds formed in flowers and enclosed in Fruits.

Angiosperms- Flowers: Help ensure pollination: Colors, shapes, fragrance Attract particular insects, birds, etc. Fruit Protects seeds Helps disperse seeds

ACTIVITY Vascular or Non vascular Plant? Spore or Seed Bearing? Dominant Stage/Generation? Label the: Gametophyte Sporophyte Describe the process of reproduction in this plant?

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