The Challenges of Life on Land

Suitable Climate: O2

http://www.bgc-jena.mpg.de/bgc-theory/uploads/Pubs/2008-PaleoJ-AK-F1.jpg

Fig. 3.3 in Willis and McElwain 2002

Suitable Climate: CO2

Rodinia (1 bya)

https://webspace.utexas.edu/cokerwr/www/slides/anacatlan/rodinia2.jpg

Rodinia Breakup (750 mya)Land

http://www.clas.ufl.edu/users/jmeert/rod.jpg

http://www.paleoportal.org/kiosk/sample_site/period_13.html

Gondwana and EuroAmerica (390 mya)

Land

Fig. 3.2 in Willis and McElwain 2002

Glaciers, Land and Sea

Soil Formation: Fossil Evidence for Well Established Soil Profiles

Ordovician (440 MYA)

Willis and McElwain 2002

Soil Formation: Mechanical

Soil Formation: Weathering (Oxidation)

Soil Formation: Weathering (Microbe and Acid Rain Mediated Breakdown)

Cyanobacterial Mats

Willis and McElwain 2002

Estimated CO2 Levels

Soil Formation: Role of Lichens

(400 MYA) (650-550 MYA?)

Soil Formation: Nutrient Leaching

The Transition to Land

Submerged Chara The First Land Plants

FOSSIL VASCULAR TISSUE

(Willis and McElwain 2002)

“Tracheids” (430 MYA) “Tubes” (400 MYA)

FOSSIL STOMATES

(~ 380 MYA)Willis and McElwain 2002

FOSSIL CUTICLE

http://www.ucmp.berkeley.edu/IB181/VPL/Pres/PresVG.html

(Silurian: 430 MYA)

(Modern)(Fossil)

FOSSIL ROOTS

(408 MYA – Early Devonian)

(450 –430 MYA Late Ordovician – Early Silurian)

FOSSIL DISPERSAL UNITS

“SPORANGIA” or “GAMETANGIA”

(428 MYA – Silurian)

Cooksonia

Life Cycles

Haplontic Alternation of Generations

First Plant: Cooksonia

(428 MYA – Silurian)

Cooksonia

(428 MYA – Silurian)

Deposits in Ireland and Elsewhere

(A Few)

Cooksonia

(400 MYA – Early Devonian)

Aglaophyton major(= Rhynia major)

(Rhynie Chert – Scotland)

Aglaophyton major(= Rhynia major)

Aglaophyton major(= Rhynia major)

“Rhizomes/Rhizoids”

Aglaophyton major(= Rhynia major)

(400 MYA – Early Devonian)

(Rhynie Chert – Scotland)

(400 MYA – Early Devonian)

Rhynia gwynne-vaughnii

(Rhynie Chert – Scotland)

Next Time: Bryophytes