Nov 19 2009

Nov 19 2009 - LIFE HISTORIES, POPULATION STRUCTURE, and...

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Unformatted text preview: LIFE HISTORIES, POPULATION STRUCTURE, and SPECIATION in the SEA Levinton, Chapter 6 (some already assigned) Jones, G. et al. 1999. Self-recruitment in a coral reef sh population. Nature 402:802-804. Knowlton N, Weigt LA, Soloranzo LA, Mills DK, Bermingham E 1993 Divergence in proteins, mitochondrial DNA, and reproductive compatibility across the isthmus of Panama. Science 260: 1629-1632 I. Life histories A. Allocation of resources to maintenance, growth and reproduction 1. semelparous 2. iteroparous B. Larval forms 1. brooded 2. lecithotrophic (yolky, non-feeding) 3. planktotrophic (feeding) C. Dispersal 1. behavior versus physical processes 2. local retention 3. long distance dispersal II. Population Structure and Phylogeography - geographic distribution of genetic variation within species A. Patterns of genetic variation give clues as to how new species are formed 1. All populations homogeneous -- high gene Fow 2. All populations genetically distinct -- leads to endemic species 3. Sharp breaks at distinct geographic locations B. Case study: Cape Canaveral, Florida 1. Many species show same phylogeographic break 2. Breaks consistent with lorida sea level changes C. Case study: Isthmus of Panama III. Reproductive Isolating Mechanisms and Speciation A. Gamete recognition- hybridization prevented by egg/sperm interaction e.g., abalone lysin - sperm protein required to dissolve the jelly coat of egg B. Temporal differences in spawning time (an hour can make a big difference) C. II. Population Structure and Phylogeography - geographic distribution of genetic variation within species A. Patterns of genetic variation give clues as to how new species are formed 1. All populations homogeneous -- high gene Fow 2. All populations genetically distinct -- leads to endemic species 3. Sharp breaks at distinct geographic locations B. Case study: Cape Canaveral, Florida 1. Many species show same phylogeographic break 2. Breaks consistent with lorida sea level changes C. Case study: Isthmus of Panama III. Reproductive Isolating Mechanisms and Speciation A. Gamete recognition- hybridization prevented by egg/sperm interaction e.g., abalone lysin - sperm protein required to dissolve the jelly coat of egg B. Temporal differences in spawning time (an hour can make a big difference) C. Hybrid breakdown Semelparous- breed once and die salmon invest in the spawning run (already studied) cephalopods (squid/octopus) Iteroparous- reproduce on multiple occasions red urchin may live 100 years and produce millions of gametes each time it spawns Marine invertebrate larvae All marine invertebrates pass through larval stages Free swimming (pelagic) feeding larvae ( planktotrophic larvae ) Pelagic non-feeding larvae ( lecithotrophic larvae ) Larval stages within the egg, which hatches into a metamorphosed juvenile ( direct development ) Direct development Non-pelagic Planktotrophic (feeding larva) Lecithotrophic (non-feeding larva) Pelagic Holoplankton: spend entire life in the water column (e.g., copepods)spend entire life in the water column (e....
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Nov 19 2009 - LIFE HISTORIES, POPULATION STRUCTURE, and...

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