Post on 21-Dec-2015
Plant Ecology - Chapter 20
Paleoecology
Paleoecology
The study of historical ecologyChanges in global patterns of vegetation, diversityDriven by ecological, evolutionary processes
Paleoecology
Plants invaded land during the Paleozoic era, during the later Ordovician and SilurianMajor time of evolution, diversification
Paleoecology
Diversity of biotic interactions developed earlyMycorrhizae, herbivory, animal pollination, animal seed dispersal
Paleoecology
Fossil carbon deposits formed from plants during Carboniferous periodCoal from remains of wetland plants (ferns, mosses, gymnosperms)
Paleoecology
Oil, gas developed from mostly marine plankton (phyto-, zoo-), and maybe wetland plantsDramatic climate change at end of Carboniferous - drier - seed plants began to dominate
Paleoecology
Mesozoic era was time of major tectonic plate movementEncompassed Triassic, Jurassic, and Cretaceous periods
Paleoecology
Moved from supercontinent Pangaea to breakup into current continentsImproved conditions for plant growth, diversification
Paleoecology
Ferns, seed ferns, gymnosperms became the dominant floraCO2 levels 3-4 X higher than today provided warm climate and plentiful CO2 for photosynthesis
Paleoecology
Decline in CO2 (248-65 mya) changed conditions for plantsCooler, more seasonalityChanging climate and continental breakup led to development, diversification of angiosperms
Paleoecology
Asteroid impact at end of Mesozoic (65 mya, K-T boundary)Impact debris and/or massive fires led to massive animal and plant extinctionsDinosaurs, and 25-80% of N. Amer, plants (more in south, fewer in north)
Paleoecology
Continued decline in CO2 concentrations (chemical reactions during new mountain weathering) resulted in slow, re-evolution of new species of angiospermsEvolution of C4 grasses from C3 ancestorsDo better at low CO2
Paleoecology
Recent trends?Global changes in CO2?
Change in C3 and C4 plant abundance, distribution?
Paleoecology
Microfossils - pollen grainsMacrofossils - leaves, stems, flowersUsed to understand changing plant communities, changing climates
Paleoecology
Glacial and interglacial cycling100,000 yearsChange in angle, degree of tilt of Earth’s axis
Paleoecology
Change in species present in MN from 22,000 ya to presentSpruce, ash, birchPine, elm, oakGrassesNow pines,oaks,sedges
Paleoecology
Can track shifts in species distribution through time