BIOLOGY 1M03 Lecture Notes - Lecture 13: Cambrian Explosion, Phanerozoic, Burgess Shale
15 May 2017
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Document Summary
Ediacaran fossils are small, soft-bodied, simple multicellular organisms. Burgess shale fossils are diverse, large animals with hard parts. Preserve the diversity of life in different periods. Conclude that there was a rapid diversification events. Habitat bias: some preserve better than other. Taxonomic bias: some organisms with hard body part preserve better than those with soft body parts. Temporal bias: around more recently compared to ancient ones. Abundance bias: things that were plentiful have more fossils. Many major lineages of animals appeared during or just after the cambrian. Form and evolution of form has been greatly discovered by fossils. Environmental change increased oxygen concentration in atmosphere, increased thickness of ozone layer, flooding of continental shelves, increased calcium in oceans. Ecosystem engineering animals changed their environment, opening up novel ecological niches. Many major lineages of animals appeared during or just after the cambrian explosion. Different phyla show up during the time of the cambrian explosion.
