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Patterns and Processes of Evolution Macroevolutionary Patterns   Large-scale (more than a single species)   Occurs over lo...
Speciation – Isolating MechanismSpecies – group of organisms that interbreed toproduce fertile offspring under normal cond...
Patterns of ExtinctionBackground Extinction – “business asusual” extinction – slow and steadyMass Extinction – many specie...
Rates of EvolutionGradualism – change in species is slow andsteadyPunctuated Equilibrium – long periods ofstability follow...
Patterns of Macroevolution:Adaptive Radiation A single species evolves into many species Often occurs when a niche opens u...
Patterns of Macroevolution:ConvergentEvolutionOrganisms come toresemble one anotherbut evolveddifferentlySource of analogo...
CoevolutionOrganisms with close ecological relationshipsevolve togetherPollinators and flowers                            ...
The Role of Genes in Evolution In terms of genetics, evolution is the change in the frequency of alleles in a population’s...
Genetic DriftRandom change in allele frequency – changes inthe gene pool of a small population due to chanceTypes of Genet...
Genetic Drift  Founder Effect – small group colonizes a  new habitat                                             10
Molecular Evolution Molecular Clocks – use mutation rates in DNA to estimate time two species have been evolving independe...
Molecular Evolution: Hox Genes Genes which control an organism’s basic body plan   Anterior/posterior ends   Limbs, wings ...
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Bio 163 patterns of evolution and genes lmk 2013

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Bio 163 patterns of evolution and genes lmk 2013

  1. 1. Patterns and Processes of Evolution Macroevolutionary Patterns Large-scale (more than a single species) Occurs over long periods of time Microevolution Small-scale (within a single species) Forms variations in populations 1
  2. 2. Speciation – Isolating MechanismSpecies – group of organisms that interbreed toproduce fertile offspring under normal conditions –share a common gene poolSpeciation – formation of a new species Requires reproductive isolation – organisms do not interbreed; gene pools become separate Behavioral Geographic Temporal 2
  3. 3. Patterns of ExtinctionBackground Extinction – “business asusual” extinction – slow and steadyMass Extinction – many species becomeextinct over a short period of time Causes: Asteroid Volcanic eruptions Moving continents Changing sea levels 3
  4. 4. Rates of EvolutionGradualism – change in species is slow andsteadyPunctuated Equilibrium – long periods ofstability followed by short periods of rapid change 4
  5. 5. Patterns of Macroevolution:Adaptive Radiation A single species evolves into many species Often occurs when a niche opens up 5
  6. 6. Patterns of Macroevolution:ConvergentEvolutionOrganisms come toresemble one anotherbut evolveddifferentlySource of analogousstructures!Examples: Dolphins and sharks Marsupials and mammals 6
  7. 7. CoevolutionOrganisms with close ecological relationshipsevolve togetherPollinators and flowers 7
  8. 8. The Role of Genes in Evolution In terms of genetics, evolution is the change in the frequency of alleles in a population’s gene pool Natural selection leads to that change 8
  9. 9. Genetic DriftRandom change in allele frequency – changes inthe gene pool of a small population due to chanceTypes of Genetic Drift: Bottleneck Effect – change in allele frequency following dramatic reduction in population size 9
  10. 10. Genetic Drift Founder Effect – small group colonizes a new habitat 10
  11. 11. Molecular Evolution Molecular Clocks – use mutation rates in DNA to estimate time two species have been evolving independently 11
  12. 12. Molecular Evolution: Hox Genes Genes which control an organism’s basic body plan Anterior/posterior ends Limbs, wings small sequence changes during embryological development can cause large changes in adults 12

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