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Diversity Part 2: Plants. Chapter 23 Introduction to Plants. Characteristics of Plants. Autotrophs Multicellular Eukaryotes Cell Wall is made out of Cellulose. Plant Groups. Bryophytes-Mosses (Seedless, Non-Vascular) Seedless vascular plants- Ferns Gymnosperms- Evergreens (Pine Trees)
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Diversity Part 2: Plants Chapter 23 Introduction to Plants
Characteristics of Plants • Autotrophs • Multicellular • Eukaryotes • Cell Wall is made out of Cellulose
Plant Groups • Bryophytes-Mosses (Seedless, Non-Vascular) • Seedless vascular plants- Ferns • Gymnosperms- Evergreens (Pine Trees) • Angiosperms-Flowering plants
Photosynthesis • Chemical Equation: • CO2 + H2O C6H12O6 + O2 • Word Equation: • Carbon Dioxide + Water Glucose + Oxygen Sunlight Sunlight
Common Ancestor • The common ancestor of ALL plants is thought to be Green Algae • In the early evolution of plants, they made the transition from aquatic to land environments
Importance of Mycorrhizae • Mycorrhizae is a mutualistic relationship between plants and fungi to help a plant absorb water from the soil. • This relationship helped plants transition to land.
Cuticle • Almost all plants have a cuticle covering their leaves and stems to prevent water loss • The cuticle is waxy (lots of lipids) and holds water in • The cuticle is also clear to let sunlight in for photosynthesis
Alternation of Generations • An alternation between two distinct forms or generations that reproduce differently • One generation is haploid and reproduces sexually • The other generation is diploid and reproduces asexually
Alternation of Generations By definition, all plants alternate generations Gametophyte n=haploid Sporophyte 2n=diploid
Alternation of Generations Gametophyte and Sporophyte Notice that the more advanced plants have a dominant Sporophyte and the less advanced plants have a more dominant Gametophyte
Alternation of Generations Multicellular diploid organism(2n) sporophyte mitosis meiosis Unicellular diploid zygote(2n) Unicellular haploid cells(n) (spores) fertilization Unicellularhaploid gametes(n) mitosis Multicellularhaploid organism(n) gametophyte mitosis
Cladogram Gymnosperms Angiosperms Seedless vascular plants Bryophytes Evolution of specialized cells / tissue Evolution of cuticle Green algae
Non-Vascular Plants • Bryophytes • Example: Moss
Bryophytes • They are small and low to the ground because they do not have vascular tissue • Found only in damp, moist areas on land • 1) Leaves must absorbwater for photosynthesis • 2) Sperm swims through water to reach egg in gametophyte
Bryophytes sporophyte gametophyte
Moss Life Cycle Moss Life Cycle
Cladogram Gymnosperms Angiosperms Seedless vascular plants Bryophytes Evolution of vascular tissue Evolution of specialized cells / tissue Evolution of cuticle Green algae
Seedless Vascular Plants • Example: Ferns
Key Adaptation over Nonvascular Plants • Vascular Tissue • Set of tubes that transport materials around plant • Allows plants to grow taller • Water travels up through Xylem • Sugar/Food travels throughout in Phloem
Ferns Live Further On Land • Still must livein moist areas • Sporophytegrows successfullywith vascular tissue • But sperm must still swim to egg in tiny gametophyte
Fern Life Cycle Fern Life Cycle
Cladogram Gymnosperms Angiosperms Seedless vascular plants Evolution of pollen grains / seeds Bryophytes Evolution of vascular tissue Evolution of specialized cells / tissue Evolution of cuticle Green algae
Seed Plants • Gymnosperms/Angiosperms • Example: Pine Trees or Flowers
Gymnosperms • Examples: Spruce Tree, Fir Tree, Pine Tree
Gymnosperms • Think cones (any conifer like pine trees) female ovary male pollen cone
Pine treeGymnosperms tiny gametophyte inside cone sporophyte Sporophyte Dominates
Gymnosperm Pollen Strategy • Release a lot, hope some pollinate • (Meanwhile, irritating everyone else) • Pollen is the male sperm in Gymnosperms and Angiosperms
Key Adaptations Over Seedless Plants • Seeds • Pollen Grains
Seeds • Tough coat protects newly fertilized embryo • Also contains supply of food (endosperm) to survive during dormancy period • A seed in a gymnosperm is inside the cone
Seed Dispersal Plants try to disperse offspring far away so they have a higher chance of survival. Dispersal of seeds prevents competition for water, nutrients, light, and living space.
Seed Dispersal • Dispersal by wind – wing-like structures, parachute-like structures
Seed Dispersal • Dispersal by animals – fruits have hooks that cling on animals fur, other fruits provide food for animals
Seed Dispersal • Seeds dispersal is completed by birds, small animals, wind, and water • The tough, fibrous outer covering of a coconut provides protection as well as a floatation device
Pollen Grain • Hard covering around sperm, light weight allows travel by wind • Removes water requirement for fertilization
Sperm Still Swims • At the very end when pollen lands on another plant of the same species • Pollen tube connects to ovary, sperm swim to egg
Cladogram Gymnosperms Angiosperms Evolution of flowers / fruits Seedless vascular plants Evolution of pollen grains / seeds Bryophytes Evolution of vascular tissue Evolution of specialized cells / tissue Evolution of cuticle Green algae
Angiosperms • Think flowers • Most diverse plant group
Key Adaptation Over Gymnosperms • Flowers • Adapted for pollination by animals • Attract animals to help carry pollen to the next flower • Color or scent attractors guide animals to obtain sugar from plant • Some angiosperms still wind pollinate (grass)
Angiosperms are Divided intoMonocots and Dicots • Monocots include: grasses, corn, rice, oats, wheat, orchids, lilies and palms • Dicots include: shrubs, trees (except conifers) wild flowers and some garden flowers