LectureCh.12 Inverts Paeo STUDENTS

LectureCh.12 Inverts Paeo STUDENTS - Ch. 12: Paleozoic Life...

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Ch. 12: Paleozoic Life History: Invertebrates Key Words - Cambrian Explosion - Burgess Shale - Marine Ecosystems - Mass Extinctions - Trilobites, brachiopods, archaeocyathids, acritarchs, graptolites, conodonts … The Cambrian Explosion - Abrupt appearance of animals with skeletons at the beginning of the Paleozoic - Over millions of years during the Early Cambrian - Proterozoic: mostly single-celled organisms until Ediacaran Fauna, calcareous  tubes, trails and burrows - Biological and geological factors o Warm climate after cold periods o Change of chemistry in oceans   more calcium o Basic body plans developed ( Hox  genes) Emergence of Shelly Organisms - Proterozoic: calcareous tubes - Early Cambrian: microscopic skeletonized fossils - During Cambrian Explosion: large skeletonized fossils Why an Exoskeleton? - Protcection against UV rays o Move into shallower water - Prevents drying out o Intertidal environment - SUpport o Size increase o Attachment sites for muscles - Protection against predator 1
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Present Marine Ecosystem - Pelagic organisms live in the water column o Plankton (floaters) Phytoplankton (e.g. diatoms, dinoflagellates) Zooplankton (e.g. foraminifera, radiolarians,  jellyfish) o Nekton (swimmers) E.g. fish, cephalopods - Benthic organisms live on or in the seafloor o Epifauna (animals on seafloor) o Epiflora (plants on seafloor) o Infauna (animals in seafloor) o Sessile (stay in place) or mobile - Feeding groups o Suspension-feeders o Herbivores o Carnivore-scavengers o Sediment-deposit feeders - Trophic levels o Primary producers (autotrophs)
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LectureCh.12 Inverts Paeo STUDENTS - Ch. 12: Paleozoic Life...

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