Bryophyte Gametophytes protonema gametophore Rhizoids ...
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• A spore germinates into a gametophyte • composed of a protonema and gamete‐producing gametophore • Rhizoids • Anchor gametophytes to substrate • Lack of vascular :ssues • Restricts the height of gametophytes Bryophyte Gametophytes Bryophyte Gametophytes • Mature gametophytes • produce flagellated sperm in antheridia and an egg in each archegonium • Sperm swim through a film of water to reach and fer:lize the egg Bryophyte Gametophytes Bryophyte Gametophytes Bryophyte Bryophyte Sporophytes Sporophytes • Bryophyte sporophytes • grow out of archegonia • smallest and simplest sporophytes • of all extant plant groups • consists of a foot,a seta (stalk), and a sporangium, • also called a capsule • which discharges spores through a peristome • Hornwort and moss sporophytes have stomata for gas exchange
Transcript of 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:
