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Kingdom Plantae Lower Plants, Organization, Morphology and Reproduction. Plant Evolution. Ancestor = Charophytes member of the green algae. Problems associated with movement to land. Desiccation (dehydration) Gas exchange Support of multicellular structures Reproduction
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Kingdom PlantaeLower Plants, Organization, Morphology andReproduction
Plant Evolution Ancestor = Charophytes member of the green algae
Problems associated with movement to land • Desiccation (dehydration) • Gas exchange • Support of multicellular structures • Reproduction • Spore or seed dispersal
Diploid Full # chromosomes 2n All non-gamete cells Can’t be gametes Human = 46 Haploid ½ # chromosomes n Gametes At fertilization become diploid zygote Human = 23 Alternation of generations
Alternation of generations Two Generations: • Sporophyte stage (spore-plant) • Diploid stage (2n) • Produces haploid spores by meiosis • Spores grow into gametophyte containing male or female repro structures.
Alternation of generations con’t. Two Generations: 2. Gametophyte (n) (gamete plant) a. haploid stage b. Male: has antheridia, makes sperm c. Female: has archegonia, makes eggs d. gametes produced via MITOSIS e. Sperm swim f. Fertilization produces zygote g. Grows into Sporophyte
The Liverworts (Hepatophyta) - Marchantia sp. Female Gametophyte Gemmae cups-asexual Archegonia
The Hornworts (Anthocerophyta) Anthoceros sp.
Moss plants – Bryophyta gametophyte & sporophyte generations
Adaptation to Land Problems associated with movement to land • Desiccation (dehydration) • Gas exchange • Support of multicellular structures • Reproduction • Spore or seed dispersal
Adaptation to Land (desiccation, gas xchge) • Stomata: a. Openings in leaf surface b. control H2O loss b. allow for gas exchange
Adaptation to Land (desiccation,transport) • Stomata: • Vascular Structures a. Xylem-H2O up from Roots b. Phloem-sugar around
Adaptation to Land (dessication) • Stomata: • Vascular • Cuticle a. H2O proof b. prevents dessication
Cuticle (made of cutin)
Adaptation to Land (support) • Stomata: • Vascular Structures • Support a. Lignin in cell walls b. allows for branching and larger size
Bryophytes No true roots or vascular tissue - 2 cm tall Still have a need for water (Repro)
Vascular Plants Dominant stage = sporophyte (Gametophyte hidden) Specialized organs • Roots • rhizomes • Stems • Leaves
Vascular plants con’t. Branching Some contain lignin a. structural support Vascular tissues a. Xylem b. phloem
Vascular Bundles in Monocot stem
Vascular plants con’t. Two types of growth – apical meristem a. Primary growth b. Secondary growth Sperm still flagellated Maintained stomata & cuticle
Lycophyta Psilotophyta Lycopodium sp. Psilotum sp. (microphylls) (stems only)
Sphenophyta Pterophyta – the ferns Equisetum sp.
Seed plants Purpose of the seed: A. means of dispersal of offspring B. Survive unfavorable conditions C. Stores food for embryo D. Protection from predators E. Remember “Seedy Side of Plants”
Seed plants (con’t.) Non-flagellated sperm • pollen • Moved by water, wind, insects, and animals • Forms pollen tube for sperm Egg cells a. Called ovules located inside the ovary
Seed plants con’t. Reduced gametophyte a. composed only of sperm or egg Maintained: a.vascular tissue, b.Cuticle c.stomata
Gymnosperms A. Needle-like leaves B. Found in moderately cold & dry regions C. Direct pollination ovules NOT enclosed by tissue of the sporophyte (gym= naked)
Gymnosperms – naked seed plants Phy: Ginkophyta Phy: Cycadophyta Cycads (Sego palm) Ginkgo biloba Strobili: sporophylls (leaves with sporangia)
Phylum: Gnetophyta Welwitschia Ephedra
Angiosperms • Produce flowers, seeds and fruit • Petals brightly colored to attract pollinators • Dominate the landscape
Angiosperms con’t. Pollination • Pollen grain lands on stigma and germinates • Pollen tube grows down through style into ovary releases sperm into ovules (egg cells) • Mature ovary = fruit • Mature ovule = seed
Monocots vs. Dicots Mono Dicot • 1 cotyledon 2 cotyledons • Parallel vein net-like vein • Fibrous root tap root • Flwr parts in 3 flwr parts in 4-5 • Scattered bundles bundles in ring (in the stem)