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Exploring Evolution: Phylogeny and Systematics Unraveled

Dive into the evolutionary history and biological diversity through phylogeny and systematics. Learn about the fossil record, dating techniques, geological time scale, biogeography, and constructing cladograms. Discover the fascinating world of evolutionary relationships and classifications.

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Exploring Evolution: Phylogeny and Systematics Unraveled

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  1. _____ Chapter 25 ~ __ • ~ Phylogeny & Systematics http://www.youtube.com/watch?v=D8zlUUrFK-M

  2. Phylogeny:the evolutionary history of a species • Systematics: the study of biological diversity in an evolutionary context • The fossil record: the ordered array of fossils, within layers, or strata, of sedimentary rock • Paleontologists

  3. The fossil record • Sedimentary rock: rock formed from sand and mud that once settled on the bottom of seas, lakes, and marshes • Dating: • 1- Relative~ geologic time scale; sequence of species • 2- Absolute~ radiometric dating; age using half-lives of radioactive isotopes http://www.youtube.com/watch?v=31-P9pcPStg

  4. The Geological Time Scale http://www.youtube.com/watch?v=QDqskltCixA&feature=related

  5. Biogeography: the study of the past and present distribution of species • Pangaea-250 mya √ Permian extinction • Geographic isolation-180 mya √ African/South American reptile fossil similarities √ Australian marsupials

  6. Mass extinction • Permian(250 million years ago): 90% of marine animals; Pangea merge • Cretaceous(65 million years ago): death of dinosaurs, 50% of marine species; low angle comet

  7. Phylogenetics • The tracing of evolutionary relationships (phylogenetic tree) • Linnaeus • Binomial • Genus, specific epithet • Homo sapiens • Taxon (taxa)

  8. Phylogenetic Trees • Cladistic Analysis: taxonomic approach that classifies organisms according to the order in time at which branches arise along a phylogenetic tree (cladogram) • Clade: each evolutionary branch in a cladogram • Types: • 1- Monophyletic single ancestor that gives rise to all species in that taxon and to no species in any other taxon; legitimate cladogram • 2- Polyphyletic members of a taxa are derived from 2 or more ancestral forms not common to all members; does not meet cladistic criterion • 3- Paraphyletic lacks the common ancestor that would unite the species; does not meet cladistic criterion

  9. Constructing a Cladogram • Sorting homology vs. analogy... • Homology: likenesses attributed to common ancestry • Analogy: likenesses attributed to similar ecological roles and natural selection • Convergent evolution: species from different evolutionary branches that resemble one another due to similar ecological roles

  10. A Cladogram http://www.youtube.com/watch?v=6IRz85QNjz0

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