Life Moves onto Land! Flashcards Preview

GeoSci 110 (Exam 2) > Life Moves onto Land! > Flashcards

Flashcards in Life Moves onto Land! Deck (11):

Marine Green Algae (eukaryotes) as Likely Ancestors of Earliest Land Plants

-first on land were mats of bacteria and algae

- land plants evolved from algae

- first spores form during ordovician period


Ordovician Land Plants

- seedless, non-vascular mosses

- akin to modern mosses

- uses spores instead of seeds

- no multicellular roots

- no system for transporting nutrients and water

- no leaves


Silurian Land Plants

- seedless plants with primitive vascular systems (cooksonia)

- rudimentary roots but no true leaves

- having conducting tissues of woody vessels to uptake and transfer water and nutrients which also serve as structured support


Lycopod (Devonian Land Plants)

- seedless, vascular; plants, cool swamps

- dominant trees of the late Devonian and Carboniferous coal swamps

- led to major adaptive radiation that changed the planet


First Gymnosperms (Devonian Land Plants)

- "naked seed plants" meaning the seed is not covered by the ovary

- seeds allow plants to withstand dire conditions; unbinding them from wet conditions


How did the evolution of large plants with roots affect global carbon cycle and climate?

roots pump CO2 into soils and thereby enhance chemical breakdown of silicate minerals which pulls CO2 atmosphere levels DOWN


Respiration Loop for Cycling Carbon

Trees give off Oxygen, animals take in and give off CO2 for the trees to take in and convert to oxygen


Significance of Carbon BURIAL on Atmospheric Chemistry and Global Climate

- causes atmosphere to become more oxygen rich because trees take in CO2, output Oxygen and then don't decompose (which would increase CO2)

- causes lower CO2 levels


Carbon Cycle during the Carboniferous Period (Age of Coal)

trees intake CO2 and put out oxygen

- trees die, fall in to the swamp where they are preserved

- some die and decompose, releasing CO2


Climate Change During Carboniferous

reduced rate of decomposition and high rate of burial of trees

- too many trees would normally give off CO2 were buried causing low levels of CO2


First Land Animals (Ordovician/Silurian)

BUGS! (trigonotarbids and millipedes)

- trigonotarbids appear in the late silurian; approx. 420 Ma

- millipedes after but still in late silurian