Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular...
-
date post
15-Jan-2016 -
Category
Documents
-
view
217 -
download
1
Transcript of Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular...
![Page 1: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/1.jpg)
Continuing Trends in Plant Continuing Trends in Plant EvolutionEvolution
• Extreme reduction of water-dependent gametophyte
• Vascular tissue – improved more
• Even more efficient roots, stems, leaves
• Seeds – protection/dispersal of young
• Wood – support
Green: all these are in sporophyte
![Page 2: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/2.jpg)
SeedsSeeds• Produced by sporophyte
• Immature seed = ovule (female gametophyte +)
• Mature seed functions:* Protection* Embryonic sporophyte* Food source
• Also: Pollen grains = reduced male gametophytes
![Page 3: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/3.jpg)
From Ovule to Seed
Conifer ovulate scale Conifer pollen grain
Conifer gametophytesConifer gametophytes
![Page 4: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/4.jpg)
Seeds some moreSeeds some more
• Spores not dispersed
• Reduced gametophytes* Female stays on sporophyte
* Male (pollen grain) dispersed
• Embryo stays on parent sporophyte
• Delayed sporophyte development* Dormancy
* Seed dispersal
* GerminationConifer seed
![Page 5: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/5.jpg)
WoodWood
• Secondary growth in circumference
• Increased support
• Reach great heights
![Page 6: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/6.jpg)
First seed plantsFirst seed plants
• Pregymnosperms• Early Permean• Pangea – dry, continental climates
![Page 7: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/7.jpg)
GymnospermsGymnosperms
• Seeds naked* Often born on scales (modified leaves) of cones* No fruit
• Conifers, cycads, ginkgo, gnetophytes• Some still produce motile sperm• Except for conifers, mostly tropical &
subtropical• First gymnosperms developed in late Permean
![Page 8: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/8.jpg)
Phylum ConiferophytaPhylum ConiferophytaConifersConifers
• Dominate our biomes
• Well adapted to cold & dry summers
• Life cycle typical of gymnosperms* Seeds naked – no fruit* Two kinds of cones
• Male produce spores that grow into pollen grains
• Female produce spores that grow into ovules
![Page 9: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/9.jpg)
Young &
oldfemalecones
Male cones
Pinus ponderosa
![Page 10: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/10.jpg)
Sporophyte
Gametophytes
Mei
osis
Meiosis
♀
♂
Fert
iliza
tion
Pollination
Seed
disp
ersa
l
&
germ
inati
on
Megaspores insidemegasporangiumone functional
Microspores insidemicrosporangium
♀ cone scale
Fig 30.9
![Page 11: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/11.jpg)
Gymnosperm surveyGymnosperm survey
• Conifers
• Cycads
• Ginkgo
• Gnetophytes
![Page 12: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/12.jpg)
Big Tree, Giant SequoiaSequoiadendron
JuniperJuniperus
BristleconePinePinus
![Page 13: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/13.jpg)
H.J. Andrews experimental forest, Blue River Oregon
![Page 14: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/14.jpg)
Douglas fir canopies
… to be continued
![Page 15: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/15.jpg)
Maidenhair TreeGinkgo
![Page 16: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/16.jpg)
Cycads
![Page 17: Continuing Trends in Plant Evolution Extreme reduction of water-dependent gametophyte Vascular tissue – improved more Even more efficient roots, stems,](https://reader035.fdocuments.in/reader035/viewer/2022062423/56649d495503460f94a260ed/html5/thumbnails/17.jpg)
Welwitschia
Mormon TeaEphedra