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Phylogeny

Phylogeny. Phylogeny - the evolutionary relationships among organisms. Natural classification. Phylogenetic tree - a treelike diagram that represents a hypothesis of the evolutionary history of a species or group of related organisms. Tree of Life- Universal Evolutionary Tree.

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Phylogeny

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  1. Phylogeny • Phylogeny- the evolutionary relationships among organisms. • Natural classification. • Phylogenetic tree- a treelike diagram that represents a hypothesis of the evolutionary history of a species or group of related organisms.

  2. Tree of Life- Universal Evolutionary Tree

  3. Hominid Evolutionary Tree

  4. Tree of Homosapiens L.

  5. Tree Terminology

  6. Phylogenetic trees Slanted • Cladogram • Slanted • Rectangular • Phylogram- shows divergence distances between taxa.

  7. Rectangular cladogram Phylogram Chondracanthus exasperatus Chondracanthus spinosus Chondracanthus squarrulosus

  8. Cladistics • Cladistics- a method of organizing organisms on the basis of synapomorphic characters. • Characters- morphological, chemical, developmental, and molecular. • Homologous characters- features of different species that are similar because they were inherited from a common ancestor. • Outgroup- a closely related taxon outside the group that is being analyzed. • Node- the branching point on a tree.

  9. Green algae

  10. Molecular Characters (Data)

  11. Lynn Margulis (1938-) • In 1967 proposed the endosymbiotic theory as the origin of mitochondria. • Symbiosis in Cell Evolution. • Included chloroplast evolution.

  12. Endosymbiotic Theory and the Evolution of Chloroplasts • Photosynthetic eukaryotes and their chloroplasts evolved from the engulfment of a cyanobacterium by a protozoan. • A phagocytotic protozoan took up a cyanobacterium into a food vesicle. • Instead of being digested, the cyanobacterium was retained as an endosymbiont. • The protozoan provided the alga with protection, a stable environment, and mineral nutrients. • The cyanobacterium produced carbohydrates for the protozoan. • The cell wall of the cyanobacterium was lost through evolutionary selection. • Food vesicle membrane= outer chloroplast membrane. • Plasma membrane of cyanobacterium= inner chloroplast membrane.

  13. Support for the Endosymbiotic Theory • Chloroplasts are about the same size as cyanobacteria. • Evolve oxygen in photosynthesis. • 70S ribosomes. • Chlorophyll A is the primary photosynthetic pigment in cyanobacteria and plants. • Circular prokaryotic DNA without histones. • Glaucophyta

  14. Endosymbiosis in Vorticella and Chlorella

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