Plant diversityChapter 22 Objectives: 10.0 Distinguish between monocots and dicots, angiosperms and gymnosperms, and vascular and nonvascular plants. 10.1 Describing the histology of roots, stems, leaves, and flowers 10.2 Recognizing chemical and physical adaptations of plants Examples: chemical -foul odor, bitter taste, toxicity; physical- spines, needles, broad leaves
Plants: • Def: multicellular eukaryotes with cell walls made of cellulose • Carry out photosynthesis using green pigments chlorophyll a and b • MOST are autotrophs, but some are parasites or saprobes (organisms that get nutrients from decaying materials). • Life cycles have two alternating stages: • Haploid (N) – gametophyte • Diploid (2N) – sporophyte • What is this called???
What Plants Need to Survive: • Sunlight - for energy for photosynthesis • Water and minerals – water is needed by ALL cells, and is a reactant in the process of photosynthesis • Gas exchange - Plants take in _________ and give off ___________. • Movement of water and nutrients: • Take up water through their roots, but make food in the leaves • Specialized tissues carry water up through the plant and carry food down to all parts of the plant.
Plant Kingdom • Botanists classify plants in four groups based on: • Water-conducting tissues • Seeds • Flowers
Bryophytes (Section 22-2) • Nonvascular plants – cannot transport water throughout the plant; can only obtain water by osmosis • Depend on water for reproduction • Lack true roots – rhizoids (long, thin cells) anchor them in the ground • Includes: • Mosses • Liverworts • Hornworts
Source:http://blogs.ubc.ca/biology321/?page_id=62 Source: http://commons.wikimedia.org/wiki/File:Sphagnum_-_moss_-_Moos_01.jpg/ Source: http://www.bios.niu.edu/stafstrom/bios305/bios305.html
Seedless Vascular Plants (Section 22-3) • How do bryophytes transport water? • Vascular plants have vascular tissue to conduct water and nutrients throughout the plant: • Xylem: transports water from roots to the rest of the plant • Phloem: transports solutions of nutrients and carbohydrates produced by photosynthesis • The xylem, together with lignin, which makes the cell walls rigid, allows vascular plants to grow taller than nonvascular plants.
Ferns and Their Relatives • Seedless vascular plants include: • Club mosses – look like mini pine trees • Horsetails • Ferns Source: http://www.homeopathyandmore.com/forum/viewtopic.php?t=608 Source: http://www.hubbardbrook.org/w6_tour/herb-stop/club-moss.htm
Ferns • What is alternation of generations? • The fern plant we are used to seeing is actually a diploid sporophyte. • Fern sporophytes develop haploid spores on the underside of their fronds. Source: http://www.warpedphotosblog.com/split-tip-fern-spores Source:http://gardenwink.blogspot.com/2012/06/macho-fern-cools-me-down.html
Seed Plants Divided into 2 groups: Gymnosperms – “naked seed”; seeds are on the surface of cones Angiosperms – “enclosed seed”; flowering plants Do not require water for reproduction to occur; can transfer sperm (pollen grains) by pollination (transfer of pollen – the male gametophyte – from male reproductive structures to female reproductive structures) Seeds are just fertilized plant embryos, surrounded by a protective seed coat.
Gymnosperms – Cone Bearers Includes: Gnetophytes Cycads – palm-like plants with large cones Ginkgoes – only one species (Ginkgo biloba) Conifers – pines, spruces, firs, cedars, sequoias, redwoods, junipers Source: http://www.plantzafrica.com/plantwxyz/welwitschia.htm Source: http://biology.unm.edu/ccouncil/Biology_203/Summaries/Non-floweringPlants.htm
Angiosperms – Flowering Plants Flowers are reproductive organs which contain ovaries that surround and protect the seeds. Fruit is just a wall of tissue around the seed. Very diverse group: Monocots and dicots Woody and herbaceous Annuals, biennials, and perennials
Monocots vs. Dicots • Cotyledon:the first leaf or pair of leaves produced by a seed plant. • (“seed leaf”) • Also differ in roots: • Monocots – fibrous roots • Dicots – tap roots (like carrots) Source: http://www.cfkeep.org/html/stitch.php?s=54373324154293&id=77748813831945
Woody/Herbaceous Plants; Annuals, Biennials, and Perennials • Woody plants: trees, shrubs, and vines • Herbaceous plants: • Stems are smooth and nonwoody • Includes most flowers • Annuals: go from seed, to plant, to dying in one growing season • Biennials: life cycle takes 2 years • 1st year: seed germinates, roots and short stems develop • 2nd year: stems, leaves, and flowers grow, and plant dies • Perinneals: live for many years