BIO203H5 Lecture Notes - Lecture 3: Great Oxygenation Event, Pilbara Craton, Algae
Document Summary
Evolution & impact of plants: importance: accumulated adaptations to life on land across deep time", spread diversified, terrestrial ecosystems, primary production, oxygen, humans, civilization, etc. Hadean: earth coalesces, 4550 mya, molten, 0% plants. Archean: 3500-2500 mya, 1st life ~ 3500 mya, apex chert fossils of western australia (oldest fossils) Proterozoic: cyanobacteria transformed earth 2450-2300 mya, eukaryotes common fossils by 2100 mya, first multicellular eukaryote (grypania) 2100 mya, fossils common by ~1500 mya (mesoproterozoic, filamentous algae 1600 mya. Archean & proterozoic: first life ~3500 mya, cyanobacteria, ancestors of chloroplasts, generate oxygen and fix nitrogen, great oxidation event (goe) (~2. 5 bya, banded ion formations, stromalite communities. Proterozoic: cyanobacteria goe, remain primary producers for next 2000 million years, ancestors of chloroplasts, free living in diverse (including extreme) environments. Cryogenian: 850-635 mya, snowball earth , animals= first sponges, photosynthetic eukaryotes, acritachs dip- photosynthetic protist microfossils, small communities in fresh water- green algae & algal mats.
