the plant kingdom: seed plants
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The Plant Kingdom: Seed Plants. Chapter 28. Learning Objective 1. Compare the features of gymnosperms and angiosperms. Two Groups of Seed Plants. Gymnosperms seeds are totally exposed or borne on the scales of cone ovary wall does not surround the ovules Angiosperms flowering plants - PowerPoint PPT PresentationTRANSCRIPT
The Plant Kingdom:The Plant Kingdom:Seed PlantsSeed Plants
Chapter 28 Chapter 28
Learning Objective 1Learning Objective 1
• Compare the features of Compare the features of gymnospermsgymnosperms and and angiospermsangiosperms
Two Groups of Seed PlantsTwo Groups of Seed Plants
• GymnospermsGymnosperms • seeds are totally exposed or borne on the seeds are totally exposed or borne on the
scales of conescales of cone• ovary wall does not surround the ovulesovary wall does not surround the ovules
• AngiospermsAngiosperms • flowering plants flowering plants • produce seeds within a fruit (a mature ovary)produce seeds within a fruit (a mature ovary)
Gymnosperm and Angiosperm Gymnosperm and Angiosperm EvolutionEvolution
Fig. 28-2, p. 602
Gymnosperms
Cyc
ads
Gin
kgo
es
Co
nif
ers
Gn
eto
ph
ytes
An
gio
sper
ms
Evolution of flowering plants
Evolution of seeds
KEY CONCEPTSKEY CONCEPTS
• Seed plants include gymnosperms and Seed plants include gymnosperms and angiospermsangiosperms
Learning Objective 2Learning Objective 2
• Trace the steps in the life cycle of a pineTrace the steps in the life cycle of a pine
• Compare its sporophyte and gametophyte Compare its sporophyte and gametophyte generationsgenerations
ConifersConifers
Fig. 28-3 (1), p. 603
Gymnosperms
Cyc
ads
Gin
kgo
es
Co
nif
ers
Gn
eto
ph
ytes
An
gio
sper
ms
Fig. 28-3 (a-c), p. 603
Pine Life Cycle 1Pine Life Cycle 1
• Pine treePine tree• a mature sporophytea mature sporophyte
• Pine gametophytesPine gametophytes• extremely smallextremely small• nutritionally dependent on sporophyte nutritionally dependent on sporophyte
generation generation
Pine Life Cycle 2Pine Life Cycle 2
• Pine is heterosporousPine is heterosporous• produces microspores and megaspores in produces microspores and megaspores in
separate conesseparate cones
• Male cones produce Male cones produce microsporesmicrospores that that develop into develop into pollen grainspollen grains (immature male (immature male gametophytes) gametophytes) • carried by air currents to female conescarried by air currents to female cones
Pine Life Cycle 3Pine Life Cycle 3
• Female cones produce Female cones produce megasporesmegaspores
• One of each four megaspores (meiosis) One of each four megaspores (meiosis) develops into a female gametophytedevelops into a female gametophyte• within an within an ovule (megasporangium)ovule (megasporangium)
Pine Life Cycle 4Pine Life Cycle 4
• PollinationPollination• transfer of pollen to female conestransfer of pollen to female cones
• Pollen tubePollen tube• grows through megasporangium to egg within grows through megasporangium to egg within
archegoniumarchegonium
• After After fertilizationfertilization• zygote develops into embryo encased inside zygote develops into embryo encased inside
seed adapted for wind dispersalseed adapted for wind dispersal
Pine Life CyclePine Life Cycle
Fig. 28-4, p. 604
Each scale bears two microsporangiaMicrosporangium2
Microspores, each of which develops into a pollen grain
Pollen grains are transferred to the female cone by wind 3
Scale from a male coneMale
cone 4Scale from a female cone Female
gametophyte
Each scale bears two ovules (megasporangia)
Megasporangium
Megaspore Growing pollen tubeOvule
HAPLOID (n) GAMETOPHYTE GENERATIONMeiosis FertilizationImmature
female cone
DIPLOID (2n) SPOROPHYTE GENERATION
5Zygote
Second sperm nucleus
Papery wings
Pollen tube Sperm nucleus united with egg nucleus
Seed coat
Male cones (pollen cones) 1
6
Embryo Two seeds on the upper surface of the scale
Mature female cone (seed cone)
Newly germinated seedling
Female gametophyte (nutritive tissue)Pine (mature sporophyte)
3
Insert “Pine life cycle”Insert “Pine life cycle”
pine_life_cycle.swfpine_life_cycle.swf
Learning Objective 3Learning Objective 3
• What features distinguish What features distinguish gymnospermsgymnosperms from from bryophytesbryophytes and and fernsferns??
GymnospermsGymnosperms
• Are vascular plants Are vascular plants • unlike bryophytesunlike bryophytes
• Produce seeds Produce seeds • unlike bryophytes and fernsunlike bryophytes and ferns
• Produce wind-borne pollen grainsProduce wind-borne pollen grains• unlike ferns and other seedless vascular unlike ferns and other seedless vascular
plants plants
KEY CONCEPTSKEY CONCEPTS
• Gymnosperms produce exposed seeds, Gymnosperms produce exposed seeds, usually in cones borne on the sporophytesusually in cones borne on the sporophytes
Learning Objective 4Learning Objective 4
• What are the four phyla of What are the four phyla of gymnospermsgymnosperms??
ConifersConifers (Phylum Coniferophyta)(Phylum Coniferophyta)
• Largest phylum of gymnospermsLargest phylum of gymnosperms
• Woody plants that bear Woody plants that bear needlesneedles (leaves (leaves that are usually evergreen)that are usually evergreen)• produce seeds in cones produce seeds in cones
• Most are Most are monoeciousmonoecious • have male and female reproductive parts in have male and female reproductive parts in
separate cones on same plantseparate cones on same plant
Male and Female ConesMale and Female Cones
KEY CONCEPTSKEY CONCEPTS
• Conifers are the most diverse and Conifers are the most diverse and numerous of the four living gymnosperm numerous of the four living gymnosperm phylaphyla
CycadsCycads (Phylum Cycadophyta)(Phylum Cycadophyta)
• Palmlike or fernlike in appearance Palmlike or fernlike in appearance
• Are Are dioeciousdioecious• have male and female reproductive structures have male and female reproductive structures
on separate plantson separate plants• but reproduce with pollen and seeds in but reproduce with pollen and seeds in
conelike structuresconelike structures
CycadsCycads
Fig. 28-6 (1), p. 605
Gymnosperms
Cyc
ads
Gin
kgo
es
Co
nif
ers
Gn
eto
ph
ytes
An
gio
sper
ms
Fig. 28-6a, p. 605
Female strobilus (seed cone)
Fig. 28-6b, p. 605
Phylum GinkgophytaPhylum Ginkgophyta
• Ginkgo bilobaGinkgo biloba• only surviving species in phylumonly surviving species in phylum• deciduous, dioecious treedeciduous, dioecious tree
• Female Female ginkgoginkgo produces fleshy seeds produces fleshy seeds directly on branchesdirectly on branches
GinkgoGinkgo
Fig. 28-7 (1), p. 606
Gymnosperms
Cyc
ads
Gin
kgo
es
Co
nif
ers
Gn
eto
ph
ytes
An
gio
sper
ms
Fig. 28-7a, p. 606
Fig. 28-7b, p. 606
GnetophytesGnetophytes (Phylum Gnetophyta)(Phylum Gnetophyta)
• Share some traits with angiospermsShare some traits with angiosperms
Fig. 28-8 (1), p. 607
Gymnosperms
Cyc
ads
Gin
kgo
es
Co
nif
ers
Gn
eto
ph
ytes
An
gio
sper
ms
GnetophytesGnetophytes
Learning Objective 5Learning Objective 5
• What features distinguish What features distinguish flowering plantsflowering plants from other plants?from other plants?
Flowering PlantsFlowering Plants
• Angiosperms (phylum Anthophyta)Angiosperms (phylum Anthophyta)
• Vascular plants that produce flowers and Vascular plants that produce flowers and seeds enclosed within a seeds enclosed within a fruitfruit
• Most diverse and successful plant groupMost diverse and successful plant group
Flowering PlantsFlowering Plants
Flowering PlantsFlowering Plants
• FlowerFlower• sepals, petals, stamens,sepals, petals, stamens, carpelscarpels• functions in sexual reproductionfunctions in sexual reproduction
• Ovules enclosed within Ovules enclosed within ovaryovary• unlike gymnospermsunlike gymnosperms
• After fertilizationAfter fertilization• ovules become seedsovules become seeds• ovary develops into fruitovary develops into fruit
Floral Floral StructureStructure
Fig. 28-10a, p. 609
Fig. 28-10b, p. 609
Female floral parts Male floral parts
Pollen grain (each will produce two sperm cells)
Stigma
StylePISTIL (consisting of one or more carpels)
AntherSTAMEN
Ovary FilamentOvules (each producing one egg cell)
Petal
SepalReceptacle
Peduncle
Parts of a FlowerParts of a Flower
Fig. 28-11a, p. 610
Petals Sepals
Fig. 28-11b, p. 610
Stamen
Pistil
Simple and Simple and Compound Compound
PistilsPistils
Fig. 28-12a, p. 611
Stigma
Ovules
Style
OvaryOvary wall
Fig. 28-12b, p. 611
One carpelOvules
Stigma
Style
Ovary wall
Ovary
Fig. 28-12b, p. 611
Ovary
Stigma
Style
One carpel
Ovary wall
Ovules
Stepped Art
KEY CONCEPTSKEY CONCEPTS
• Angiosperms produce ovules enclosed Angiosperms produce ovules enclosed within carpels; following fertilization, seeds within carpels; following fertilization, seeds develop from the ovules, and the ovaries develop from the ovules, and the ovaries of carpels become fruitsof carpels become fruits
Learning Objective 6Learning Objective 6
• Explain the life cycle of a Explain the life cycle of a flowering plantflowering plant
• Describe Describe double fertilizationdouble fertilization
Flowering Plant Life Cycle 1Flowering Plant Life Cycle 1
• Sporophyte generation dominantSporophyte generation dominant
• Gametophytes extremely reduced in sizeGametophytes extremely reduced in size• nutritionally dependent on sporophyte nutritionally dependent on sporophyte
generation generation
• HeterosporousHeterosporous• produce microspores, megaspores in flowerproduce microspores, megaspores in flower
Flowering Plant Life Cycle 2Flowering Plant Life Cycle 2
• MicrosporeMicrospore develops into a pollen grain develops into a pollen grain (immature male gametophyte) (immature male gametophyte)
• One of each four One of each four megasporesmegaspores (meiosis) (meiosis) develops into develops into embryo sacembryo sac (female (female gametophyte) gametophyte)
Flowering Plant Life Cycle 3Flowering Plant Life Cycle 3
• Embryo sac contains seven cells with Embryo sac contains seven cells with eight nucleieight nuclei
• Egg cell and central cell with two Egg cell and central cell with two polar polar nucleinuclei participate in fertilization participate in fertilization
Flowering Plant Life CycleFlowering Plant Life Cycle
Fig. 28-13, p. 612
Developing pollen tube of mature male gametophyte
Pollination6Each microspore
develops into a pollen grain
Embryo sac (mature female gametophyte)5 Pollen grain
(immature male
gametophyte)
MicrosporeTetrad of microspores Pollen
tube3
Polar nucleiMegaspore Two sperm
cellsEgg nucleus
HAPLOID (n) GAMETOPHYTE GENERATION
Meiosis Double fertilizationDIPLOID (2n)
SPOROPHYTE GENERATION
74 2
MegasporocyteEndosperm (3n)
Ovary
Zygote (2n)
Fruit
8
EmbryoSeed
Microsporocytes within microsporangia
Seed coat
SeedlingAnther 1Flower of mature sporophyte
Megasporangium (ovule)
Double FertilizationDouble Fertilization
• Characteristic of flowering plantsCharacteristic of flowering plants
• Results in formation ofResults in formation of• diploid zygotediploid zygote• triploid triploid endospermendosperm
Insert “Monocot life Insert “Monocot life cycle”cycle”
angiosperm_cycle.swfangiosperm_cycle.swf
Explore plant life cycles by Explore plant life cycles by clicking on the figures in clicking on the figures in
ThomsonNOW.ThomsonNOW.
Learning Objective 7Learning Objective 7
• Contrast Contrast eudicotseudicots and and monocotsmonocots, the two , the two largest classes of flowering plantslargest classes of flowering plants
MonocotsMonocots (Class Monocotyledones)(Class Monocotyledones)
• Most have floral parts in threesMost have floral parts in threes
• Seeds each contain Seeds each contain 11 cotyledoncotyledon
• EndospermEndosperm • nutritive tissue in mature seedsnutritive tissue in mature seeds
Eudicots (Class Eudicotyledones)Eudicots (Class Eudicotyledones)
• Usually have floral parts in fours or fivesUsually have floral parts in fours or fives• or multiples thereofor multiples thereof
• Seeds each contain Seeds each contain 2 cotyledons2 cotyledons
• Cotyledons Cotyledons • nutritive organs in mature seedsnutritive organs in mature seeds• absorbed nutrients in endospermabsorbed nutrients in endosperm
Monocot and EudicotMonocot and Eudicot
Learning Objective 8Learning Objective 8
• What are the evolutionary adaptations of What are the evolutionary adaptations of flowering plants?flowering plants?
ReproductionReproduction
• Flowering plants reproduce sexually by Flowering plants reproduce sexually by forming forming flowersflowers
• After After double fertilizationdouble fertilization, seeds form within , seeds form within fruitsfruits
• Wind, water, insects, animals transfer Wind, water, insects, animals transfer pollen grainspollen grains
StructuresStructures
• Efficient water-conducting Efficient water-conducting vessel elementsvessel elements in in xylemxylem
• Efficient carbohydrate-conducting Efficient carbohydrate-conducting sieve sieve tube elementstube elements in in phloem phloem
KEY CONCEPTSKEY CONCEPTS
• Angiosperms, which compose a single Angiosperms, which compose a single phylum, dominate the land and exhibit phylum, dominate the land and exhibit great diversity in both vegetative and great diversity in both vegetative and reproductive structuresreproductive structures
Insert “Flower parts”Insert “Flower parts”
flower_parts.swfflower_parts.swf
Learn more about flower Learn more about flower structure by clicking on the structure by clicking on the
figure in ThomsonNOW.figure in ThomsonNOW.
Learning Objective 9Learning Objective 9
• Summarize the evolution of gymnosperms Summarize the evolution of gymnosperms from seedless vascular plantsfrom seedless vascular plants
• Trace the evolution of flowering plants Trace the evolution of flowering plants from gymnospermsfrom gymnosperms
Evolution 1Evolution 1
• Seed plantsSeed plants arose from arose from seedless vascular seedless vascular plantsplants
• ProgymnospermsProgymnosperms• seedless vascular plantsseedless vascular plants• had megaphylls and “modern” woody tissuehad megaphylls and “modern” woody tissue• probably gave rise to probably gave rise to conifersconifers and and seed fernsseed ferns
• ProgymnospermProgymnosperm
• Seed FernSeed Fern
Evolution 2Evolution 2
• Seed fernsSeed ferns• probably gave rise to cycads and ginkgoprobably gave rise to cycads and ginkgo
• Evolution of Evolution of gnetophytesgnetophytes, particularly their , particularly their relationship to flowering plants, is unclearrelationship to flowering plants, is unclear
Evolution 3Evolution 3
• Flowering plantsFlowering plants probably descended from probably descended from gymnosperms with specialized featuresgymnosperms with specialized features• leaves with broad, expanded bladesleaves with broad, expanded blades• closed carpels closed carpels
• Flowering plantsFlowering plants likely arose only once likely arose only once
Fossil AngiospermsFossil Angiosperms
Fig. 28-17, p. 615
Carpel
Ovule
5 mm
Fig. 28-18, p. 615
Pistils
Scars on reproductive axis
7 mm
Evolution of Flowering PlantsEvolution of Flowering Plants
Fig. 28-19a, p. 616
Basal Angiosperms Core Angiosperms
Am
bo
rell
a
Wat
er l
ilie
s
Sta
r an
ise
Mag
no
liid
s
Mo
no
cots
Eu
dic
ots
Evolution of vessel elements
Evolution of flowering plants
Fig. 28-19b, p. 616
Fig. 28-19c, p. 616
Fig. 28-19d, p. 616
Fig. 28-19e, p. 616
KEY CONCEPTSKEY CONCEPTS
• Gymnosperms and angiosperms evolved Gymnosperms and angiosperms evolved from ancestral seedless vascular plantsfrom ancestral seedless vascular plants