BIOL 2040 Lecture Notes - Lecture 23: Paraphyly, Monophyly, Cichlid
19 Apr 2016
School
Department
Course
Professor
Document Summary
Lecture 23: rates of evolution and adaptive radiation. 543 mya start of cambrian: in cambrain, saw radiation of animal phyla. All current major animal phyla, with just a couple radiating after the early. Vendian/ediacaran: the last era of the pre-cambrian. Mostly soft-bodied creatures: animals before the cambrian, ediacaran fossils organisms tend to be round, soft-bodied impressions. The burgess shale: rock bed formed ~505 mya, found in bc. During the cambrian: lots of preserved soft and hard body parts, found lots of extinct species of extant phyla. Could be ancestral to any of the main marine arthropod lineages. Could be a fragment of an animal, could be oriented wrong: cambrian fauna were large, complex, and bilateral. Most extant animal phyla appeared during cambrian. The cambrian explosion: the radiation of animal phyla, not the appearance of all life, not the dawn of life, lots of life already existed (archaea, bacteria, etc. )
