EEMB_113_Lecture_2_Origins_F20_1per.pdf - Vertebrate Ecology and Evolution EEMB 113 Lecture 2 Vertebrate origins Course learning objectives(CLOs from

EEMB_113_Lecture_2_Origins_F20_1per.pdf - Vertebrate...

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Vertebrate Ecology and Evolution EEMB 113 Lecture 2: Vertebrate origins
Course learning objectives (CLOs from syllabus) 1. Students will be able to explain the difference between taxonomy, systematics, and phylogenetics 5. Students will be able to identify and describe extant tetrapod diversity to the level of order for all taxa, to family for select taxa 6. Students will be able to describe currently accepted hypotheses about origin of extant tetrapod groups 10.Students will be able to explain examples of apomorphy, homoplasy, convergence, and speciation in tetrapods
Vertebrate coelomates are members of the Phylum Chordata in the group DeuterostomiaDeuterostomia is characterized by a shared developmental trait, the fate of the blastopore.Why are shared traits important to the study ofBiology?
Vocabulary • Apomorphy*: A derived character • Synapomorphy*: share derived character that unites sister groups • Autapomorphy*: derived character unique to particular taxon • Symplesiomorphy*: Primitive character common to two or more clades, can not be used to establish interrelationship
Phylogenetic trees
Phylogenetic systematics aka cladistics (aka Hennigian systematics) Willi Hennig, Published works 1950s – 80s Three key features 1. Use derived characters rather than overall similarity 2. Reject taxonomic groups that include some but not all descendants of a common ancestral species 3. Insist on a system that directly reflects evolutionary relationships
Phylogenetic trees Speciation event Ancestral lineage gives rise to 2 or more daughter lineages DIVERGENCE EVENT
Phylogenetic trees Speciation event Ancestral lineage gives rise to 2 or more daughter lineages DIVERGENCE EVENT
Phylogenetic trees From ancestor to descendant Root of tree represents ancestral lineage
Phylum Chordata (Vertebrata, Urochordata, Hemichordata)

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