Plant DiversityPlant DiversityChapter 22Chapter 22

What is a Plant?What is a Plant? Plants are the base for the food chain on land.Plants are the base for the food chain on land. Provide shade, shelter and oxygenProvide shade, shelter and oxygen Evolved more than 470 million years agoEvolved more than 470 million years ago Multicellular, EukaryotesMulticellular, Eukaryotes Cell walls made of celluloseCell walls made of cellulose Photosynthesis using chlorophyll a and bPhotosynthesis using chlorophyll a and b Most are autotrophs; few parasites + saprobes Most are autotrophs; few parasites + saprobes Ex. Trees, shrubs, grasses, mosses and fernsEx. Trees, shrubs, grasses, mosses and ferns

Life CycleLife Cycle Haploid (N)-Gametophyte; gamete-producing Haploid (N)-Gametophyte; gamete-producing Diploid (2N)-Sporophyte; spore-producingDiploid (2N)-Sporophyte; spore-producing

Produce a new individual by mitosisProduce a new individual by mitosis All plants have both phases, but in different formsAll plants have both phases, but in different forms Can reproduce independently of waterCan reproduce independently of water Some also reproduce asexually (vegetative)Some also reproduce asexually (vegetative)

HaploidDiploid MEIOSIS

Spores(N)

FERTILIZATION

Sperm(N)

Eggs(N)

Section 22-1Generalized Plant Life CycleGeneralized Plant Life Cycle

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Plant SurvivalPlant Survival SunlightSunlight Water and MineralsWater and Minerals

Taken up through the rootsTaken up through the roots Movement of Water/NutrientsMovement of Water/Nutrients

Make food in their leavesMake food in their leaves Water and nutrients carried upward through tissue Water and nutrients carried upward through tissue

from soilfrom soil Gas ExchangeGas Exchange

Early PlantsEarly Plants Evolved from multicellular green algaeEvolved from multicellular green algae First plants were dependent on waterFirst plants were dependent on water Similar to today’s mosses in structure and Similar to today’s mosses in structure and

growth close to the groundgrowth close to the ground Evolved different adaptations for terrestrial Evolved different adaptations for terrestrial

environmentsenvironments

Cone-bearingplants

Ferns andtheir relatives

Seeds

Water-Conducting(Vascular) Tissue

Section 22-1

Cladogram of Plant Cladogram of Plant GroupsGroups

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Overview of the Plant KingdomOverview of the Plant Kingdom Divided into four groups based on water-Divided into four groups based on water-

conducting tissues, seeds and flowersconducting tissues, seeds and flowers Reproductive structures and body plan are also Reproductive structures and body plan are also

consideredconsidered Compare DNA sequences of various speciesCompare DNA sequences of various species Deep Green (1994)-Evidence that first plants Deep Green (1994)-Evidence that first plants

evolved from green algae that lived in fresh evolved from green algae that lived in fresh waterwater

Cone-bearing plants760 species

Ferns andtheir relatives11,000 species

Mosses andtheir relatives15,600 species

Floweringplants235,000 species

Section 22-1 The Diversity of PlantsThe Diversity of Plants

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BryophytesBryophytes

Nonvascular plantsNonvascular plants 1) Mosses (in swamps)1) Mosses (in swamps) Can live in harsh environmentsCan live in harsh environments Rhizoid-long, thin cells absorb water and minerals Rhizoid-long, thin cells absorb water and minerals

and anchor them to the ground and anchor them to the ground 2) Liverworts and 3) hornworts 2) Liverworts and 3) hornworts Use osmosis to draw up waterUse osmosis to draw up water

Water needed for reproductionWater needed for reproduction Act as natural sponge and form peat mossAct as natural sponge and form peat moss

BryophytesBryophytes MossesMosses LiverwortsLiverworts Hornworts Hornworts http://www.ghettodriveby.com/hornworts/http://www.ghettodriveby.com/hornworts/

Seedless Vascular PlantsSeedless Vascular Plants Vascular tissue-Specialized to conduct water Vascular tissue-Specialized to conduct water

and nutrients thought he body of the plantand nutrients thought he body of the plant Xylem-form of vascular tissue that carries water Xylem-form of vascular tissue that carries water

upward from the roots to every part of the plantupward from the roots to every part of the plant Phloem-transports solutions of nutrients and Phloem-transports solutions of nutrients and

carbohydrates from photosynthesiscarbohydrates from photosynthesis Tree rings in the lower trunk indicate the tree ageTree rings in the lower trunk indicate the tree age

Formed by cell division in thin layers inside bark Formed by cell division in thin layers inside bark Width of the bands indicate environmental conditions Width of the bands indicate environmental conditions

for each year (Ex. Drought conditions)for each year (Ex. Drought conditions)

FernsFerns Evolved 350 million years agoEvolved 350 million years ago Roots-Underground organs to absorb water Roots-Underground organs to absorb water

and minerals with water-conducting tissueand minerals with water-conducting tissue Leaves-Photosynthetic organ that contain Leaves-Photosynthetic organ that contain

bundles of vascular tissuebundles of vascular tissue Veins-Made of xylem and phloemVeins-Made of xylem and phloem Stems-Connect roots and leaves Stems-Connect roots and leaves

Seed PlantsSeed Plants Gymnosperms-Seeds on cone surfacesGymnosperms-Seeds on cone surfaces

Conifers, Cycads, Ginkgoes and gnetophytesConifers, Cycads, Ginkgoes and gnetophytes Angiosperms-Flowering plants with seeds in Angiosperms-Flowering plants with seeds in

tissue layerstissue layers Flowers or cones transfer sperm by pollination Flowers or cones transfer sperm by pollination

and protect embryos in seedsand protect embryos in seeds Life cycle alternates between gametophytes Life cycle alternates between gametophytes

and sporophyteand sporophyte

Seed coat

Embryo

Storedfood supply

Seed

A

B

Section 22-4

The Structure of a The Structure of a SeedSeed

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Reproduction without WaterReproduction without Water Cones-sporophyte structures which are seeding Cones-sporophyte structures which are seeding

bearing for gymnospermsbearing for gymnosperms Flowers-Seed-bearing structure of angiospermsFlowers-Seed-bearing structure of angiosperms Pollen Grains-Contain male gametophytesPollen Grains-Contain male gametophytes Seeds-Embryo of seed plant with seed coat and food Seeds-Embryo of seed plant with seed coat and food

supplysupply Eaten and dispersed by animals or stick to their fur Eaten and dispersed by animals or stick to their fur Fossils from 30 million years agoFossils from 30 million years ago

A Bee With Pollen On It’s LegA Bee With Pollen On It’s Leg

GymnospermsGymnosperms Cone Bearers / “naked seed”Cone Bearers / “naked seed”1)1) Gnetophytes: Gnetophytes:

a) Ex. a) Ex. WelwitschiaWelwitschia-Namibian desert with large, -Namibian desert with large, leathery leaves; spread across the groundleathery leaves; spread across the ground

2)2) Cycads- (Cycadophyta):Cycads- (Cycadophyta):a) Palm-link plants with large conesa) Palm-link plants with large conesb) Appeared during Triassic Period (225 million b) Appeared during Triassic Period (225 million years ago)years ago)

c) Grow in tropical and subtropical placesc) Grow in tropical and subtropical places

WelwitschiaWelwitschia mirabilis mirabilis,a ,a GnetophyteGnetophyte. And . And Zamia Zamia pseudoparasiticapseudoparasitica,a Cycad,a Cycad..

http://www.conifers.org/pinophyta.htmhttp://www.conifers.org/pinophyta.htm

GymnospermsGymnosperms Ginkgoes-Only Ginkgoes-Only Ginkgo bilobaGinkgo biloba currently exists currently exists

One of the oldest seed plant species alive todayOne of the oldest seed plant species alive today Cultivated in China and planted around templesCultivated in China and planted around temples Often planted in urban settings in U.S. due to resistance to Often planted in urban settings in U.S. due to resistance to

air pollutionair pollution Conifers-(Coniferophyta)Conifers-(Coniferophyta)

Ex. Pines, spruces, firs, cedars, sequoias, redwoodsEx. Pines, spruces, firs, cedars, sequoias, redwoods Long, thin leaves (Ex. Pine needles)-reduces surface Long, thin leaves (Ex. Pine needles)-reduces surface

area, waxy layerarea, waxy layer Most are “evergreens” with cycling of needlesMost are “evergreens” with cycling of needles

GinkgoGinkgo and and Pseudotsuga menziesiiPseudotsuga menziesii,a Conifer,a Conifer. .

http://www.conifers.org/pinophyta.htmhttp://www.conifers.org/pinophyta.htm

AngiospermsAngiosperms Phylum Anthophyta “enclosed seed”Phylum Anthophyta “enclosed seed” Cretaceous Period (135 million years ago) Cretaceous Period (135 million years ago)

arrivalarrival Dominate Earth’s plant lifeDominate Earth’s plant life Reproduce with flowers or fruitsReproduce with flowers or fruits Ovary develops into fruits to protect seed and Ovary develops into fruits to protect seed and

for dispersalfor dispersal Fruit-thick wall of tissue surrounding the seedFruit-thick wall of tissue surrounding the seed

Seed Dispersal By Wind And Seed Dispersal By Wind And General Flower StructureGeneral Flower Structure

http://science.kennesaw.edu/biophys/biodiversity/plants/plpix5.htmhttp://science.kennesaw.edu/biophys/biodiversity/plants/plpix5.htm

Monocots and DicotsMonocots and Dicots Cotyledons-Seed leaves in the plant embryoCotyledons-Seed leaves in the plant embryo Monocots-One seed leaf, parallel veins, Monocots-One seed leaf, parallel veins,

multiples of 3 floral parts, vascular bundles multiples of 3 floral parts, vascular bundles scattered and fibrous rootsscattered and fibrous roots

Dicots-Two seed leaves, branched veins, Dicots-Two seed leaves, branched veins, multiples of 4 or 5 floral parts, vascular multiples of 4 or 5 floral parts, vascular bundles in a ring and a taprootbundles in a ring and a taproot

Monocots Dicots

Seeds

Leaves

Flowers

Stems

Roots

Single cotyledon

Parallel veins

Floral parts often in multiples of 3

Vascularbundlesscattered throughout stem

Fibrous roots

Two cotyledons

Branched veins

Floral parts often in multiplesof 4 or 5

Vascularbundlesarranged ina ring

Taproot

Section 22-5

Comparison ofComparison ofMonocots and DicotsMonocots and Dicots

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Monocots and DicotsMonocots and Dicotshttp://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookPLANTANATII.htmlhttp://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookPLANTANATII.html

Diversity of AngiospermsDiversity of Angiosperms Wood plants made of cells with thick cell Wood plants made of cells with thick cell

walls (Trees, shrubs and vines)walls (Trees, shrubs and vines) (Ex. Grapes and Ivy vines)(Ex. Grapes and Ivy vines) (Ex. Blueberries and rose bushes)(Ex. Blueberries and rose bushes)

Herbaceous plants-No wood production as Herbaceous plants-No wood production as they grow (Ex. Dandelions, zinnias, they grow (Ex. Dandelions, zinnias, sunflowers and petunias)sunflowers and petunias)

Rose Bush, Grape Vine, Zinnias and Rose Bush, Grape Vine, Zinnias and PetuniasPetunias

http://www.flowers.vg/flowers/petunia01.htmhttp://www.flowers.vg/flowers/petunia01.htm

Diversity of AngiospermsDiversity of Angiosperms Annuals-Complete a life-cycle within one growing Annuals-Complete a life-cycle within one growing

seasonseason (Ex. Marigolds, petunias, pansies, zinnias, wheat and (Ex. Marigolds, petunias, pansies, zinnias, wheat and

cucumbers)cucumbers) Biennials-Complete their life cycle in 2 yearsBiennials-Complete their life cycle in 2 years

Year 1-germinate and grow roots & very short stemsYear 1-germinate and grow roots & very short stems Year 2-Grow new stems and leaves and produce flowers Year 2-Grow new stems and leaves and produce flowers

and seedsand seeds (Ex. Primrose, parsley, celery)(Ex. Primrose, parsley, celery)

Perennials-Live for more than 2 yearsPerennials-Live for more than 2 years (Ex. Asparagus, grasses-herbaceous stems)(Ex. Asparagus, grasses-herbaceous stems) (Ex. Maple trees-wood stem)(Ex. Maple trees-wood stem)

Primrose, Marigolds, Ornamental Primrose, Marigolds, Ornamental GrassesGrasses

http://landscaping.about.com/cs/designexamples1/l/bllandscaping10.htmhttp://landscaping.about.com/cs/designexamples1/l/bllandscaping10.htm