bryophyte gametophytes protonema gametophore rhizoids

• Asporegerminatesintoagametophyte

• composedofaprotonemaandgamete‐producing

gametophore

• Rhizoids

• Anchorgametophytestosubstrate

• Lackofvascular:ssues

• Restrictstheheightofgametophytes

BryophyteGametophytesBryophyteGametophytes

• Maturegametophytes

• produceflagellatedsperminantheridiaandan

eggineacharchegonium

• Spermswimthroughafilmofwatertoreachand

fer:lizetheegg

BryophyteGametophytesBryophyteGametophytes

BryophyteBryophyteSporophytesSporophytes

• Bryophytesporophytes

• growoutofarchegonia

• smallestandsimplestsporophytes

• ofallextantplantgroups

• consistsofafoot,aseta(stalk),andasporangium,

• alsocalledacapsule

• whichdischargessporesthroughaperistome

• Hornwortandmosssporophyteshavestomataforgasexchange

Fig.29‐9a

ThallusGametophore offemale gametophyte

Marchantia polymorpha,a “thalloid” liverwort

Marchantia sporophyte (LM)

Sporophyte

FootSeta

Capsule(sporangium)

500 µm

Fig.29‐9b

Plagiochiladeltoidea,a “leafy”liverwort

Fig.29‐9c

An Anthoceroshornwort species

Sporophyte

Gametophyte

Fig.29‐9d

Gametophyte

Seta

CapsuleSporophyte(a sturdyplant thattakes monthsto grow)

Polytrichum commune,hairy-cap moss

• Sphagnum,or“peatmoss,”

• formsextensivedepositsofpar:allydecayedorganicmaterial

• knownaspeat

• animportantglobalreservoiroforganiccarbon

MossMoss

Fig.29‐11

(a) Peat being harvested

(b) “Tollund Man,” a bog mummy

FernsandotherseedlessvascularplantsFernsandotherseedlessvascularplants

• Bryophytesandbryophyte‐likeplants

• weretheprevalentvegeta:onduringthefirst100millionyearsofplantevolu:on

• Vascularplants

• begantodiversifyduringtheDevonianandCarboniferousperiods

• Vascular:ssue

• allowedtheseplantstogrowtall

• Seedlessvascularplants

• haveflagellatedspermandareusuallyrestrictedtomoistenvironments

Fig.29‐UN2

Nonvascular plants (bryophytes)

Seedless vascular plants

Gymnosperms

Angiosperms

OriginsandTraitsofVascularPlantsOriginsandTraitsofVascularPlants

• Fossilsoftheforerunnersofvascularplants

• datebackabout420millionyears

• Theseearly:nyplantshadindependent,branching

sporophytes

• Livingvascularplantsarecharacterizedby:

• Lifecycleswithdominantsporophytes

• Vascular:ssuescalledxylemandphloem

• Well‐developedrootsandleaves

LifeCycleswithDominantLifeCycleswithDominantSporophytesSporophytes

• Incontrastwithbryophytes

• sporophytesofseedlessvascularplantsarethelargergenera:on

• asinthefern

• Thegametophytes

• :nyplantsthatgrowonorbelowthesoilsurface

Fig.29‐13‐1

Key

Haploid (n)Diploid (2n)

MEIOSISSporedispersal

Sporangium

SporangiumMaturesporophyte(2n)

Sorus

Fiddlehead

Fig.29‐13‐2

Key

Haploid (n)Diploid (2n)

MEIOSISSporedispersal

Sporangium

SporangiumMaturesporophyte(2n)

Sorus

Fiddlehead

Spore(n)

Younggametophyte

Maturegametophyte(n) Archegonium

Egg

Antheridium

Sperm

FERTILIZATION

Fig.29‐13‐3

Key

Haploid (n)Diploid (2n)

MEIOSISSporedispersal

Sporangium

SporangiumMaturesporophyte(2n)

Sorus

Fiddlehead

Spore(n)

Younggametophyte

Maturegametophyte(n) Archegonium

Egg

Antheridium

Sperm

FERTILIZATIONNewsporophyte

Gametophyte

Zygote(2n)

TransportinXylemandPhloemTransportinXylemandPhloem• Vascularplantshavetwotypesofvascular:ssue:

• xylemandphloem

• Xylem

• conductsmostofthewaterandminerals

• includesdeadcellscalledtracheids

• strengthenedbyligninandprovidestructuralsupport

• Phloem

• Movessugars,aminoacids,andotherorganicproducts

• consistsoflivingcells

EvoluOonofRootsEvoluOonofRoots

• Roots

• Organsthatanchorvascularplants

• enablevascularplantstoabsorbwater

• andnutrientsfromthesoil

• Mayhaveevolvedfromsubterraneanstems

EvoluOonofLeavesEvoluOonofLeaves• Leaves

• organsthatincreasethesurfaceareaofvascularplants

• therebycapturingmoresolarenergy

• usedforphotosynthesis

• Leavesarecategorizedbytwotypes:

– Microphylls

– leaveswithasinglevein

– Megaphylls

– leaveswithahighlybranchedvascularsystem

• Accordingtoonemodelofevolu:on

• microphyllsevolvedfirst

• asoutgrowthsofstems

EvoluOonofLeavesEvoluOonofLeaves

SporophyllsSporophyllsandSporeVariaOonsandSporeVariaOons

• Sporophylls

• modifiedleaveswithsporangia

• Sori

• clustersofsporangiaontheundersidesofsporophylls

• Strobili

• cone‐likestructuresformedfromgroupsofsporophylls

• homosporous

• produceonetypeofsporethatdevelopsintoabisexualgametophyte

• Mostseedlessvascularplants

• heterosporous

• producemegasporesthatgiverisetofemalegametophytes

• andmicrosporesthatgiverisetomalegametophytes

• Allseedplantsandsomeseedlessvascularplants

SporophyllsSporophyllsandSporeVariaOonsandSporeVariaOons

Fig.29‐UN3

Homosporous spore production

Sporangiumon sporophyll

Singletype of spore

Typically abisexualgametophyte

Eggs

Sperm

Eggs

Sperm

Heterosporous spore productionMegasporangiumon megasporophyll Megaspore Female

gametophyte

Malegametophyte

MicrosporeMicrosporangiumon microsporophyll

ClassificaOonofSeedlessVascularPlantsClassificaOonofSeedlessVascularPlants

• Therearetwophylaofseedlessvascularplants:

– PhylumLycophyta

– includesclubmosses,spikemosses,and

quillworts

– PhylumPterophyta

– includesferns,horsetails,andwhiskfernsandtheirrela:ves

Fig.29‐15a

Lycophytes (Phylum Lycophyta)

Selaginella apoda,a spike moss

Isoetesgunnii,a quillwort

Strobili(clusters ofsporophylls)

2.5 cm

Diphasiastrum tristachyum, a club moss1 cm

Fig.29‐15e

Pterophytes (Phylum Pterophyta)Athyriumfilix-femina,lady fern

Vegetative stem

Strobilus onfertile stem

1.5

cm

25 c

m

2.5

cm

Psilotumnudum,a whiskfern

Equisetumarvense,fieldhorsetail

PhylumPhylumLycophytaLycophyta::

• Giantlycophytes

• thrivedformillionsofyearsinmoistswamps

• Survivingspeciesaresmallherbaceousplants

• Clubmossesandspikemosseshavevascular

:ssues

• andarenottruemosses

PhylumPhylumPterophytaPterophyta• Ferns

• mostdiverseseedlessvascularplants

• morethan12,000species

• Horsetails

• diverseduringtheCarboniferousperiod

• nowrestrictedtothegenusEquisetum

• Whiskferns

• resembleancestralvascularplants

• butarecloselyrelatedtomodernferns

TheSignificanceofSeedlessVascularPlantsTheSignificanceofSeedlessVascularPlants

• Ancestorsofmodernlycophytes,horsetails,andferns

• grewtogreatheightsduringtheDevonianandCarboniferous

• formingthefirstforests

• Increasedphotosynthesis

• mayhavehelpedproducetheglobalcooling

• attheendoftheCarboniferousperiod

• ThedecayingplantsoftheseCarboniferousforestseventuallybecamecoal

Fig.29‐16

Youshouldnowbeableto:Youshouldnowbeableto:

1. Describefoursharedcharacteris:csandfourdis:nctcharacteris:csbetweencharophytesandlandplants

2. Dis:nguishbetweenthephylumBryophytaandbryophytes

3. Diagramandlabelthelifecycleofabryophyte

4. Explainwhymostbryophytesgrowclosetothegroundandarerestrictedtoperiodicallymoistenvironments

5. Describethreetraitsthatcharacterizemodernvascularplantsandexplainhowthesetraitshavecontributedtosuccessonland

6. Explainhowvascularplantsdifferfrombryophytes

7. Dis:nguishbetweenthefollowingpairsofterms:microphyllandmegaphyll;homosporousandheterosporous

8. Diagramandlabelthelifecycleofaseedlessvascularplant

Youshouldnowbeableto:Youshouldnowbeableto: