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Unformatted text preview: 1 GY 112: Earth History UNIVERSITY OF SOUTH ALABAMA Paleozoic Life forms 2: Chordates (Fish to amphibians) Last time we covered… Paleozoic Fossils Part 1 A) The first “plants” (Archean-Proterozoic) B) Diversification (Paleozoic-Mesozoic) C) Domination (Mesozoic-Cenozoic) Paleozoic Life forms: Plants Oceans are full of beasties Marine invertebrates Terrestrial plant evolution apparently did not occur until the mid- Silurian… Paleozoic Life forms: Plants A bit more info on prokaryotic evolution is needed • The first prokaryotes were heterotrophs (they simply digested carbon from other organisms; “consumers in the food chain”). By the way, all animals are heterotrophs. •The next stage in prokaryotic evolution were the autotrophs (they produced their own “food” 1) Nitrifying bacteria – use ammonia (NH 3 ) to manufacture their food 2) Sulfur bacteria – use hydrogen sulfide (H 2 S) to manufacture their food •A type of autotroph uses CO 2 and sunlight to manufacture their food; Photoautotrophs . CO 2 + 6 H 2 O + sunlight ⇒ C 6 H 12 O 6 + 6O 2 Paleozoic Life forms: Plants The earliest tracheophytes (e.g., Cooksonia Sp.), were small (<5cm high) and lacked leaves and roots. ht p:/ www.fossilmuseum.net/plantfossils/Buthotrephus/PS2996aL.jpg htp:/content.answers.com/main/content/wp/en-commons Paleozoic Life forms: Plants The next major evolutionary development? Leaves. The first leaves were almost welded onto the trunks of the plants (which now stood rather tall; e.g., Lepidodendron sp.). They were called the “scale trees”....
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- Spring '12
- Evolution, Paleozoic Life forms