Transcript Plant Ecology

Plant Ecology - Chapter 20
Paleoecology
Paleoecology
The study of
historical ecology
Changes in global
patterns of
vegetation, diversity
Driven by
ecological,
evolutionary
processes
Paleoecology
Plants invaded land
during the Paleozoic
era, during the later
Ordovician and
Silurian
Major time of
evolution,
diversification
Paleoecology
Diversity of biotic
interactions
developed early
Mycorrhizae,
herbivory, animal
pollination, animal
seed dispersal
Paleoecology
Fossil carbon
deposits formed
from plants during
Carboniferous
period
Coal from remains
of wetland plants
(ferns, mosses,
gymnosperms)
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
Paleoecology
Mesozoic era was
time of major
tectonic plate
movement
Encompassed
Triassic, Jurassic,
and Cretaceous
periods
Paleoecology
Moved from
supercontinent
Pangaea to breakup
into current
continents
Improved conditions
for plant growth,
diversification
Paleoecology
Ferns, seed ferns,
gymnosperms
became the
dominant flora
CO2 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 plants
Cooler, more
seasonality
Changing 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 extinctions
Dinosaurs, 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
angiosperms
Evolution of C4 grasses
from C3 ancestors
Do better at low CO2
Paleoecology
Recent trends?
Global changes in
CO2?
Change in C3 and
C4 plant abundance,
distribution?
Paleoecology
Microfossils - pollen
grains
Macrofossils leaves, stems,
flowers
Used to understand
changing plant
communities,
changing climates
Paleoecology
Glacial and
interglacial cycling
100,000 years
Change in angle,
degree of tilt of
Earth’s axis
Paleoecology
Change in species
present in MN from
22,000 ya to present
Spruce, ash, birch
Pine, elm, oak
Grasses
Now
pines,oaks,sedges
Paleoecology
Can track shifts in
species distribution
through time