BIOL 2003 Lecture Notes - Lecture 3: Ediacaran Biota, Rangeomorph, Polyphyly
Classification, Phylogeny and the Fossil Record
September 16, 2015
Recap: Protostomes vs Deuterostomes
• based on embryonic development
• protostome – spiral cleavage
• deuterostrome – radial cleavage
• protostome – mouth first
• deuterostrome – anus first
• different formation of coelom
Splits of Animal Groups:
• porifera
• placozoa
• radiate
• bilateria
o Protostomia
1. Lophotrochozoa
2. Ecdysozoa
o Deuterostomia (gill slits)
Hiearchial Groupings:
• Kingdom - Animalia
• Phylum – Chordata
• Class – Vertebrata
• Order – Mammalia
• Family –Hominidae
• Genus – Homo
• Species – sapien
Key Points with Taxonomy:
• Taxa (sing. taxon) – organisms in the rank
• Binomial name: Genus species
• Systematics: species are grouped based on evolutionary relatedness
o Evolutionary descent
o Descendants share key features
Phylogeny:
• Uses organismal characters
o Morphological, developmental embryological, genetic/molecular…
• Similar characters can be homoplasy OR homology
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Document Summary
Recap: protostomes vs deuterostomes: based on embryonic development, protostome spiral cleavage, deuterostrome radial cleavage, protostome mouth first, deuterostrome anus first, different formation of coelom. Splits of animal groups: porifera, placozoa, bilateria radiate, protostomia, lophotrochozoa, ecdysozoa, deuterostomia (gill slits) Hiearchial groupings: kingdom - animalia, order mammalia, phylum chordata, class vertebrata, family hominidae, genus homo. Species sapien: taxa (sing. taxon) organisms in the rank, binomial name: genus species. Systematics: species are grouped based on evolutionary relatedness: evolutionary descent, descendants share key features, uses organismal characters, morphological, developmental (cid:523)embryological(cid:524), genetic/molecular . The ediacaran: 630-543 million years ago (right before cambrian, ediacaran biota unique groups (rangeomorphs extinct by cambrian era), early cnidarians, established many major phyla and worms. Paleozoic era and cambrian: 543 mya to 485 mya, all extant phyla evolved, fossils can tell us about early evolution of animal phyla. Edicaran paleozoic (cambrian-permian) mesozoic (triassic-jurassic-cretaceous) cenozoic.
