270 likes | 506 Views
Paleozoic Life Ch 12 & 13 This artistic diorama models the living Environment for the Burgess shale organisms. Visible Life. In the Cambrian system of rocks, a large number of visible complex species were observed. Life had been single-celled simple organisms for billions of years.
E N D
Paleozoic Life Ch 12 & 13 This artistic diorama models the living Environment for the Burgess shale organisms
Visible Life In the Cambrian system of rocks, a large number of visible complex species were observed. Life had been single-celled simple organisms for billions of years. The “sudden” appearance of large, well-preserved organisms caused scientists to use the term “Cambrian Explosion” Not so fast – the Cambrian period lasted for 54 million years. Life appeared to evolve more rapidly but there had been many steps Leading to the new life forms. The Ediacara fossils were multi-celled soft-bodied predecessors Increase in oxygen may be responsible for increase in body size.Ocean chemistry was evolving and may have increased in calcium. Cambrian continents were apart allowing more marine habitat. Sauk transgression created more shallow marine habitat on shore. Global warming was occurring.
What are advantages to having an exoskeleton? Protection from UV light, allowing organisms into shallow waters Prevents drying out in intertidal locations Supporting skeleton (shell) allows for increased size and attachment of muscle Protection from predators
Marine ecosystem: plankton (phyto- zoo-), nekton, benthos, sessile, mobile, epifauna, infauna
Marine Ecosystem • Where and how animals and plants live in the marine ecosystem Plankton: Jelly fish Sessile epiflora: seaweed Nekton: fish cephalopod Sessile epifauna: bivalve Benthos: d-k crinoid coral
Marine Ecosystem Mobile epifauna: gastropod, starfish Infauna: worm, bivalve
Marine Ecosystem Suspension feeders: coral crinoid bivalve
Marine Ecosystem worm sediment-deposit feeder Carnivores-scavengers: starfish Herbivores: gastropod
Trilobites: Conspicuous Cambrian fossils Fig. 1, p. 248
Agnostus Believed to be blind Other trilobites have Compound eyes Fig. 3, p. 249
Middle Ordovician Fig. 12-9, p. 251
Late Ordovician Fig. 12-11a, p. 252
Middle DevonianNew York State Eurypterid Fig. 12-14, p. 254
Late Devonian Ammonoid Fig. 12-15, p. 254
http://www.youtube.com/watch?v=s1xfRc4SDsw&NR=1&feature=fvwp