ºÝºÝߣ

ºÝºÝߣShare a Scribd company logo

Lecture4 life cycle of plants

•Download as PPT, PDF•
•
R
rpritchett

1. The document discusses the evolution of early land plants and their adaptation to living on land through the development of adaptations like mechanical strength, light catching surfaces, and systems for water transport and nutrient absorption. 2. It describes the alternation of generations life cycle, where plants alternate between a haploid gametophyte generation and diploid sporophyte generation. 3. Key examples of early land plants discussed include mosses, which produce sporophytes on top of gametophyte bodies, and ferns, which demonstrate a free-living gametophyte phase and a dominant sporophyte phase.

1 of 26
Downloaded 160 times
Alternation of generations in mosses and ferns 1. Adaptation to living on land and the first land plants 2. History of evolution of major plant types 3. Alternation of generations 4. Moss life cycle 5. Fern life cycle
1. Adaptation to living on land and the first land plants The land that land plants colonized was hostile to life. Soil development was minimal. Land plants grow in an environment that does not support them. They require several adaptations to be successful: mechanical strength for support, exposed light catching surfaces, anchoring system, conducting system for water, system for obtaining mineral nutrients, a way to restrict water loss in desiccating air, a means of reproducing and dispersing on land
Advantages of being small An advantage of being small is that many of the requirements for living on land are minimized. Close to the soil surface the environment can be almost aquatic – even if it does not rain continuously. Then the principal adaptation required becomes the ability to withstand the dry periods between the wet.
Devonian plant community Devonian plant community found at Rhynie, in Scotland. A reed-like marsh, 370-380 million years ago. Simple dichotomous branching MAIN FEATURES !5 to 30 cm tall No roots Stomata with guard cells Most had a central vascular strand Cuticle Asteroxylon had leaves –without a vascular connection Sporangia Asteroxylon
Lycopodium Lycopodium, club mosses, share many features with Asteroxylon, but they do have roots. http://web.utk.edu/~flemin00/pteridology/pteridology.html
Horsetails: Equisetum http://www.ansci.cornell.edu/cgi-bin/db2www/plant_indiv.d2w/PHOTO?keynum=36 Equisetum arvense Vegetative and reproductive axis bearing sporangia The ‘scouring rush’
History of plant groups 2. History of evolution of major plant types Fig. 17.3A
Alternation of generations 3. Alternation of generations Fig. 17.4
4. Moss life cycle Fig. 17.5
Ìý
Moss sporophyte Top of capsule
Developing protonema
Moss antheridium and archegonium
Fig. 17.3A
Fern life cycle 5. Fern life cycle Fig 17.6
Ìý
Sporangia Polypodium spp sori sporangia http://departments.bloomu.edu/biology/chamuris/concepts2/labimg.html A sorus
Magnified sporangia Polypodium spp Sporangia Developing spores
Gametophyte Polypodium spp Gametophyte Developing sporophyte
Arrangement of sporangia on two ferns In lines on a broadleaved type At the end of the leaves Adiantum Asplenium
Tree ferns Cibotium menziesii in habitat in Hawaii.Ìý Photo courtesy of Peter Richardson. Cyathea australis with the uncurling croziers visible.Ìý Photo courtesy of Scott Ridges
Coal formation Jungle-like forests of the Carboniferous were dominated by giant ancestors of club mosses, horsetails, ferns, conifers, and cycads. Most of the plant fossils found in the coals and associated sedimentary rocks show no annual growth rings, suggesting rapid growth rates and lack of seasonal variation in the climate (tropical). Anaerobic conditions and periodic inundations of the sea
Early Carboniferous Britain Ice cap Equator Appalachians
Late Carboniferous Britain Ice cap Equator Appalachians
Fossil Lepidophylloides Lepidophylloides is the name assigned to the leaves of the Lepidodendron tree . Ìý Rock Type: Gray shale Age: Middle Pennsylvanian Period, approx. 312 million years. http://www.clearlight.com/~mhieb/WVFossils/Lepidophylloides1.html
Sections you need to have read 17.1 17.2 17.3 17.4 17.5 17.6 17.7 Courses that deal with this topic Botany 113 Plant Identification and Classification Botany 350 Introduction to Plant Geography Geology 203 Evolution of the Earth

More Related Content

Lecture4 life cycle of plants

  • 1. Alternation of generations in mosses and ferns 1. Adaptation to living on land and the first land plants 2. History of evolution of major plant types 3. Alternation of generations 4. Moss life cycle 5. Fern life cycle
  • 2. 1. Adaptation to living on land and the first land plants The land that land plants colonized was hostile to life. Soil development was minimal. Land plants grow in an environment that does not support them. They require several adaptations to be successful: mechanical strength for support, exposed light catching surfaces, anchoring system, conducting system for water, system for obtaining mineral nutrients, a way to restrict water loss in desiccating air, a means of reproducing and dispersing on land
  • 3. Advantages of being small An advantage of being small is that many of the requirements for living on land are minimized. Close to the soil surface the environment can be almost aquatic – even if it does not rain continuously. Then the principal adaptation required becomes the ability to withstand the dry periods between the wet.
  • 4. Devonian plant community Devonian plant community found at Rhynie, in Scotland. A reed-like marsh, 370-380 million years ago. Simple dichotomous branching MAIN FEATURES !5 to 30 cm tall No roots Stomata with guard cells Most had a central vascular strand Cuticle Asteroxylon had leaves –without a vascular connection Sporangia Asteroxylon
  • 5. Lycopodium Lycopodium, club mosses, share many features with Asteroxylon, but they do have roots. http://web.utk.edu/~flemin00/pteridology/pteridology.html
  • 6. Horsetails: Equisetum http://www.ansci.cornell.edu/cgi-bin/db2www/plant_indiv.d2w/PHOTO?keynum=36 Equisetum arvense Vegetative and reproductive axis bearing sporangia The ‘scouring rush’
  • 7. History of plant groups 2. History of evolution of major plant types Fig. 17.3A
  • 8. Alternation of generations 3. Alternation of generations Fig. 17.4
  • 9. 4. Moss life cycle Fig. 17.5
  • 10. Ìý
  • 11. Moss sporophyte Top of capsule
  • 13. Moss antheridium and archegonium
  • 15. Fern life cycle 5. Fern life cycle Fig 17.6
  • 16. Ìý
  • 17. Sporangia Polypodium spp sori sporangia http://departments.bloomu.edu/biology/chamuris/concepts2/labimg.html A sorus
  • 18. Magnified sporangia Polypodium spp Sporangia Developing spores
  • 19. Gametophyte Polypodium spp Gametophyte Developing sporophyte
  • 20. Arrangement of sporangia on two ferns In lines on a broadleaved type At the end of the leaves Adiantum Asplenium
  • 21. Tree ferns Cibotium menziesii in habitat in Hawaii.Ìý Photo courtesy of Peter Richardson. Cyathea australis with the uncurling croziers visible.Ìý Photo courtesy of Scott Ridges
  • 22. Coal formation Jungle-like forests of the Carboniferous were dominated by giant ancestors of club mosses, horsetails, ferns, conifers, and cycads. Most of the plant fossils found in the coals and associated sedimentary rocks show no annual growth rings, suggesting rapid growth rates and lack of seasonal variation in the climate (tropical). Anaerobic conditions and periodic inundations of the sea
  • 23. Early Carboniferous Britain Ice cap Equator Appalachians
  • 24. Late Carboniferous Britain Ice cap Equator Appalachians
  • 25. Fossil Lepidophylloides Lepidophylloides is the name assigned to the leaves of the Lepidodendron tree . Ìý Rock Type: Gray shale Age: Middle Pennsylvanian Period, approx. 312 million years. http://www.clearlight.com/~mhieb/WVFossils/Lepidophylloides1.html
  • 26. Sections you need to have read 17.1 17.2 17.3 17.4 17.5 17.6 17.7 Courses that deal with this topic Botany 113 Plant Identification and Classification Botany 350 Introduction to Plant Geography Geology 203 Evolution of the Earth