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The Plant Kingdom Bio 20 Unit 4 From “The Plant Kingdom Notes” Adapted from notes by T. Greenshields (2004) Revised by S. Pipke-Painchaud (2005) Plant Characteristics all plants are photosynthetic since they contain chlorophyll plants are multicellular organisms plants are divided into 2 main categories, or phyla Bryophytes Vascular Plants Classification of Plants Land Plants Bryophytes true mosses hornworts Vascular Plants liverworts seeds angiosperms gymnosperms spores club mosses horsetails ferns Phylum Bryophyta - 24 000 species Bryophytes have no vascular tissue to conduct fluids throughout the body. This restricts them to moist environments and a small size. ** ** - bryophytes continued... Bryophytes do not have true roots, stems or leaves instead of roots, the plant is anchored by thread-like rhizoids Many bryophytes become dormant in dry conditions Bryophyte Reproduction Need moisture for sexual reproduction to occur since flagellated sperm must swim to the egg life cycle includes alternation of generations between: haploid (n) phase (gametophyte) diploid (2n) phase (sporophyte) The sporophyte capsule forms haploid spores. These spores are released and grow into gametophyte plants with a half set of genes the gametophytes then produce either sperm or eggs. The sperm from male gametophytes swim to eggs in female gametophytes. The egg is fertilized and grows into a 2n sporophyte. Classes of Bryophytes 3 classes: true mosses, liverworts, and hornworts 1. Mosses are the largest class and include sphagnum moss, some of which formed after the Pleistocene Ice Age and has grown ever since. In Ireland, sphagnum moss from bogs is drained and peat is burned in electric generators. Ireland relies heavily on coal (non-renewable resource) - peat is also a limited supply. Bog People • anything that dies in a bog is well preserved • Peat contains sphagnum associated plants • it contains pollen grains from surrounding plants which provides a log of the vegetative changes over the years • Animals and humans are well preserved Let’s Meet the Bog People Website Tollund Man 2. Liverworts and, ** 3. Hornworts also grow in moist areas and often have “lobed” bodies ** Vascular Plants Phylum Tracheophyta - 211 000 species most vascular plants have adapted to conserve water so that they can survive on land have conducting tissue to transport water and dissolved nutrients (xylem and phloem) true leaves and stems and well-developed root systems Vascular plants continued ... adapted to conserve water (waxy cuticle) reproduce by spores or seeds and do not require water for sexual reproduction life cycle also exhibits alternation of generations, though usually contained within one plant 2 groups: seed-producing and sporeproducing Spore - producing 1. Club mosses (Division Lycophyta) are not mosses but evergreen plants that are usually under 40 cm tall ** many species produce spores in club-shaped cones at the tip of short-upright stems ** 2. Horsetails (Division Sphenophyta) have hollow, jointed stems growing from horizontal underground stems. They have small, scale-like leaves (at each joint) and contain silica and so are harsh to the touch. People used them to scour pans. (hence the common name scouring rushes) ** The Giant Horsetails Intro to Sphenophyta Image from: Digital Saskatchewn & Kenton Letkeman © 2005 3. Ferns like the club mosses and horsetails, these reproduce by spores, which can be seen as small brown spots (sorus/ sporangia) on the undersides of their leaves ** lives in the shade with underground stems and roots. Everything above ground is leaves. Life cycle includes a tiny gametophyte stage and a large sporophyte stage Ferns continued …. after spores on the underside of the leaf have developed they disperse ** water is needed to reproduce spore lands somewhere and a small heartshaped prothallus appears ** sperm swim through rain or dew from antheridium (male part) to archegonium (female part) where fertilization occurs Ferns continued ... young sporophyte develops and grows into what we would recognize as a fern most ferns live in the tropics but some occur in forest ecosystems Psaronius (extinct) was several meters tall and had leaves up to 2 meters long. It had a diameter up to 30 cm. Was not made of wood but instead supported by a mantle of extra roots and leaves. Fern Lifecycle Try these sites for lifecycle examples: - New Zealand Plants - University of Aukland - Sanata Rosa Tropicals Images of Ferns: - Discover Olympic Seed-Producing 1. Gymnosperms (conifers) - 700 species most conifers are evergreens most are woody trees or shrubs with needles or scales for leaves. This is well adapted to dry environments due to the low surface to volume ratio and thick waxy cuticle produce naked seeds grouped in cones (attached to the upper surface of the scales) includes juniper, larch, pine, spruce, fir Gymnosperms continued ….. Bristlecone Pine in California and Nevada can be 4900 years old. The wood is not good for logging but tourists break pieces off to take home - Bristlecone Pine website Redwoods of California are some of tallest trees in world. Tallest tree is 372 ft high. The largest is 273 ft high, 84 ft wide and 4000 years old.** Ginkgos nearly went extinct but were saved by monks. They have high disease resistance and pollution tolerance Gymnosperm Reproduction cone cross section ** scale with seeds ** pollen grain ** Cone cross section Scale with seeds Pollen Grain Seed-Producing con’t . . . 2. Angiosperms (flowering plants) - 200 000 species flower is the reproductive structure sperm is transferred in pollen grains to the egg within the carpel of a flower. This zygote develops into the seed, protected within a fruit. Part of the seed embryo consists of one or two modified leaves called cotyledons, and a root. The seed also has a food supply, either as endosperm or in the embryo itself. 2 classes of Angiosperms Monocotyledons: single cotyledon in the seed embryo parallel veins in long, narrow leaves flower parts in multiples of 3 ** includes grasses, sedges, cereal crops, rice and corn important food source for humans Dicotyledons: two cotyledons in the seed embryo branched venation in broad leaves flower parts in multiples of 4 or 5 ** includes most fruits, vegetables, trees, and shrubs Summary Bryophytes have no vascular tissue, need water to reproduce, and are considered to be the simplest land plants Tracheophytes (vascular plants) have vascular tissue and do not need water to reproduce. They reproduce by seeds or by spores seed bearing plants are considered to be more advanced than spore-bearing plants angiosperms are considered to be the most advanced land plants Land Plants Bryophytes mosses liverw's Vascular Plants hornw's seeds angio's spores gymno's How do plants influence the economy? Spice Cinnamon, nutmeg, ginger, licorise Pharmaceutical Good: White willow, coco leaves, mustard, comphrey chamomile Bad: marijuana, opium, magic mushrooms, cocain Poisons: Rhubarb leaves, Stinging Nettle, Lily of the Valley, Cassava Root (Tapioca), Mtn Ash Berries Textile Industry Cotton, Hemp Fuel/Oil Industry Ethanol, Canola Lumber Industry Oak, Walnut, Pine, Maple, etc. Food Industry Fruits, Vegetables, Grains, etc. The End Please refer to your Kingdom Plantae Handout