plants Flashcards
what was the earth’s temp like before plants?
7°C warmer
what was the ocean like before plants?
more anoxia in the deep oceans
what did the land have before plants?
critter tracks and freshwater algae
what process caused plant growth?
2 endosymbiotic events c. 2.7 Ga
first endosymbiotic process
- prokaryotic host cell engulfs a-proteobacterium which contains DNA
- forms a non-photosynthetic proto-eukaryotic cell which has a nucleus and mitochondria
second process of endosymbiosis
- the proto-eukarytic cell engulfs cyanobacterium and forms a photosynthetic eukaryotic cell because it has chloroplasts
what were the earliest land plants?
cryptospores 475 Ma
when were vascular plant fossils found?
425 Ma
when were root and leaf fossils found?
- late Silurian
- 420 Ma
when were giant fungi fossils found?
420-370 Ma
what is the rhynie chert?
an early Devonian sedimentary deposit with fossil detail
410 Ma
when were the first trees?
- late Devonian
- ~385 Ma
- Wattieza
- no leaves
when were the first forests?
- late Devonian
- archaeopetris
~ 375 Ma
what is plant amplification of weathering?
- a source of nutrients, especially P
- organic acids, carbonic acid, chelating agents, soil stabilisation
what are the consequences of plant weathering?
- release of P
- increased organic source C burial
- source of O2
- release of Ca and Mg from silicates
- sink of CO2 with formation of marine carbonates
- planetary cooling
