Plant Diversity

Chapter 22

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I. Introduction to Plants

A. What is a Plant Kingdom Plantae 1. Multicellular eukaryotes 2. have cell walls made of cellulose 3. develop from multicellular embryos 4. carry out photosynthesis using pigments 5. Most are autotrophs

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B. Plant Life Cycle 1. alternation of generations – alternating phases between diploid and haploid phases 2. Sporophyte – spore producing plant a. formed by meiosis, and can grow into new individuals

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3. gametophyte – gamete producing plant a. formed by mitosis, and fuses during fertilization with another gamete

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C. What Plants need to survive 1. Sunlight – for photosynthesis 2. Water a. used for photosynthesis b. used quickly 3. Minerals a. absorbed with water b. used for plant growth

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4. Gas Exchange a. Use CO 2 for photosynthesis b. Use O 2 for cellular respiration 5. Movement of water and nutrients – to all parts of the plant

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D. Early Plants 1. Origins in the water a. the first plants probably evolved from protists

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2. The First Plants a. similar to current day moss b. simple structure c. grew close to the damp ground d. dependent on water for life cycles

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E. Overview of the Plant Kingdom 1. Plant kingdom is divided into 5 major groups based on four features a. Embryo formation b. water-conducting tissues c. seeds d. flowers

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2. Types of Plants a. Green Algae b. Mosses and their relatives c. Ferns and their relatives d. Cone-bearing plants e. Flowering plants

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II. Green Algae

A. Any photosynthetic eukaryote that doesn’t live on land B. Most aquatic (fresh, salt, moist soil) C. Single celled or branching filaments D. Absorb water and nutrients through cell membranes

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III. Bryophytes

A. Bryophytes 1. nonvascular plants a. vascular tissue 1) tissue that conducts water and nutrients

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2. Depend on water for reproduction 3. live close to ground and draw water by osmosis only a few cm above ground

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B. Groups of Bryophytes

1. Mosses – phylum Bryophyta a. live in areas with lots of water b. adapted to live in nutrient-poor soils

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c. tolerate low temps – polar regions have a lot of mosses d. rhizoids – long thin cells that anchor mosses to the ground 1) also absorb water and nutrients

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2. Liverworts – Phylum Hepaticophyta a. thin flat leaves attached to the ground

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b. Gemmae – small multicellular reproductive structure – divide by mitosis to make a new individual (asexually) c. Live in soil that is damp year round

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3. Hornworts – Phylum Anthocerophyta a. Live in soil that is damp year round b. thin flat leaves shaped like a tiny green horn attached to the ground

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C. Life Cycle of Bryophytes 1. Dependence on Water a. sperm must swim to the egg b. use water, dew, or rain drops

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2. Life Cycle of Moss a. Gametophyte stage 1) moss spore lands in a moist place 2) germination occurs, mass of filaments grows called a protonema 3) rhizoids form 4) antheridia – structure that forms sperm 5) archegonia - structure that forms eggs

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b. Sporophyte Stage 1) sperm and egg join to form a diploid zygote 2) grows out of the gametophyte 3) forms along stalk with a capsule 4) capsule matures and opens, releasing spores

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IV. Seedless Vascular Plants

A. Vascular Tissue 1. Specialized cells conducting water and nutrients throughout the plant

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B. Evolution of Vascular Tissue: A Transport System 1. Xylem a. transport water up from the roots to the plant b. Tracheids – specialized cells in vascular plants that conduct water

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2. Phloem a. transports nutrients and carbohydrates from the leaves to the rest of the plant 3. lignin – substance that makes cell walls rigid

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C. Have true roots, stems, and leaves D. Types of Seedless Vascular Plants

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1. Club Mosses – Phylum Lycophyta a. small, live in moist wood lands b. miniature pines

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2. Horsetails – Phylum Arthrophyta a. Leaves contain silica b. nonphotosynthetic leaves arranged in whorls

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3. Ferns – phylum Pterophyta a. Rhizomes – underground stems b. can live in area with little light c. live in wet or seasonally wet areas

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D. Life Cycle of Ferns

1. Diploid sporophyte is the dominant stage 2. sporangia – structure on the underside of the frond that produce haploid spores 3. sori – groups of sporangia

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4. spores germinate, develop into gametophytes 5. develops into a flat leaf shape 6. antheridia, and archegonia are on the underside of the gametophyte 7. water is needed for the sperm to swim to the egg 8. fertilization produces a diploid zygote that develops into a sporophyte plant

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V. Seed Plants

Gymnosperms – seeds form in/on cones Angiosperms – flowering plants A. Reproduction free from water 1. seed plants reproduce without water 2. use flowers or cones, pollination, and embryos protected in seeds 3. important evolutionary adaptation

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4. Cones and Flowers a. cones - seed bearing structure in gymnosperms b. Flowers – seed bearing structures of angiosperms

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5. pollen a. pollen grain – contain the sperm b. pollination – transfer of pollen from the male reproductive structure to the female reproductive structure

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6. Seeds a. seed – embryo of a plant that is enclosed by a covering and food supply b. seed coat – surrounds and protects the embryo and keeps the contents of the seed from drying out

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B. Gymnosperms – Cone Bearers 1. Gnetophytes – phylum Gnetophyta a. reproductive cell is centered into cones

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2. Cycads – phylum Cycadophyta a. Palm-like plants, with large cones b. grow in tropic and subtropic areas

http://www.4to40.com/earth/geography/htm/plantsindex.asp?counter=126 36

3. Ginkgoes – phylum Ginkgophyta a. living fossil – has changed little over the years of existence b. male and female trees

37 http://www.arborday.org/trees/treeguide/ TreeDetail.cfm?ID=162

4. Conifers – phylum Coniferophyta a. pine trees, spruces, cedars, redwoods b. Most are evergreens

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Oldest Trees Bristlecone pines

are found in California, Nevada, and Utah. Some of these trees in eastern California's White Mountains are more than 4,500 years old. The oldest known living Great Basin bristlecone pine is a tree named Methuselah, and is more than 4,700 years old. Picture – Biology text - Information http://ecoworld.com/plants/ecoworld_plants_home .cfm

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VI. Angiosperms – Flowering Plants

A. Flowers and Fruits 1. flowers are the reproductive organs a. attract animals to transport pollen b. contain ovaries 2. Fruit – a wall of tissue surrounding the seed a. animals eat fruit, and help spread seeds

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B. Diversity of Angiosperms

1. plants are arranged into groups, often groups can overlap 2. Monocots & Dicots a. Monocotyledonae (monocots) – one seed leaf 1) parallel veins 2) vascular bundles scattered throughout the stem 3) fibrous roots

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b. dicotyledonae (dicots) – have 2 seed leaves 1) Branched veins 2) vascular bundles arranged in a ring 3) taproot

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Comparison of Monocots and Dicots Section 22-5 Seeds Monocots

Single cotyledon

Leaves Flowers Stems

Parallel veins Floral parts often in multiples of 3 Vascular bundles scattered throughout stem

Roots

Fibrous roots Two cotyledons

Dicots

Branched veins Floral parts often in multiples of 4 or 5 Vascular bundles arranged in a ring Taproot 43

3. Woody and Herbaceous Plants a. Woodiness 1) plants have thick cell walls that support the plant body 2) trees, shrubs, vines b. Herbaceous 1) plants with a smooth non woody stems 2) dandelions, petunias, sunflowers

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4. Annuals, Biennials, and Perennials a. Annuals 1) complete a life cycle in one growing season 2) replant each year b. Biennials 1) complete their life cycle in two years 2) grow the first year, flower the second year

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c. Perennials 1) live for more than two years 2) woody stems, or a herbaceous stem that are replaced each spring

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Video

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