1. Plant Ecology - Chapter 20 Paleoecology

2. The study of historical ecology Changes in global patterns of vegetation, diversity Driven by ecological, evolutionary processes

3. Paleoecology Plants invaded land during the Paleozoic era, during the later Ordovician and Silurian Major time of evolution, diversification

4. Paleoecology Diversity of biotic interactions developed early Mycorrhizae, herbivory, animal pollination, animal seed dispersal

5. Paleoecology Fossil carbon deposits formed from plants during Carboniferous period Coal from remains of wetland plants (ferns, mosses, gymnosperms)

6. Paleoecology Oil, gas developed from mostly marine plankton (phyto-, zoo-), and maybe wetland plants Dramatic climate change at end of Carboniferous - drier - seed plants began to dominate

7. Paleoecology Mesozoic era was time of major tectonic plate movement Encompassed Triassic, Jurassic, and Cretaceous periods

8. Paleoecology Moved from supercontinent Pangaea to breakup into current continents Improved conditions for plant growth, diversification

9. Paleoecology Ferns, seed ferns, gymnosperms became the dominant flora CO 2 levels 3-4 X higher than today provided warm climate and plentiful CO 2 for photosynthesis

10. Paleoecology Decline in CO 2 (248-65 mya) changed conditions for plants Cooler, more seasonality Changing climate and continental breakup led to development, diversification of angiosperms

11. Paleoecology Asteroid impact at end of Mesozoic (65 mya, K-T boundary) Impact debris and/or massive fires led to massive animal and plant extinctions Dinosaurs, and 25-80% of N. Amer, plants (more in south, fewer in north)

12. Paleoecology Continued decline in CO 2 concentrations (chemical reactions during new mountain weathering) resulted in slow, re-evolution of new species of angiosperms Evolution of C 4 grasses from C 3 ancestors Do better at low CO 2

13. Paleoecology Recent trends? Global changes in CO 2 ? Change in C 3 and C 4 plant abundance, distribution?

14. Paleoecology Microfossils - pollen grains Macrofossils - leaves, stems, flowers Used to understand changing plant communities, changing climates

15. Paleoecology Glacial and interglacial cycling 100,000 years Change in angle, degree of tilt of Earth’s axis

16. Paleoecology Change in species present in MN from 22,000 ya to present Spruce, ash, birch Pine, elm, oak Grasses Now pines,oaks,sedges

17. Paleoecology Can track shifts in species distribution through time