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THE ORIGIN OF SPECIES

THE ORIGIN OF SPECIES. THE ORIGIN OF SPECIES. HOW DOES EVOLUTION LEAD TO THE FORMATION OF ALL THE DIFFERENT ORGANISMS, OR SPECIES, WE SEE ON THE PLANET? FIRST WE MUST DEFINE A “SPECIES”. THE ORIGIN OF SPECIES. SPECIES BIOLOGICAL SPECIES CONCEPT

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THE ORIGIN OF SPECIES

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  1. THE ORIGIN OF SPECIES

  2. THE ORIGIN OF SPECIES • HOW DOES EVOLUTION LEAD TO THE FORMATION OF ALL THE DIFFERENT ORGANISMS, OR SPECIES, WE SEE ON THE PLANET? • FIRST WE MUST DEFINE A “SPECIES”

  3. THE ORIGIN OF SPECIES • SPECIES • BIOLOGICAL SPECIES CONCEPT • A SPECIES AS A POPULATION OR GROUP OF POPULATIONS WHOSE MEMBERS HAVE THE POTENTIAL TO INTERBREED AND PRODUCE FERTILE OFFSPRING • MORPHOLOGICAL SPECIES CONCEPT • CLASSIFICATION IS BASED MAINLY ON OBSERVABLE AND MEASURABLE PHENOTYPIC TRAITS • GENEALOGICAL SPECIES CONCEPT • A SET OF ORGANISMS WITH A UNIQUE GENETIC HISTORY • ECOLOGICAL SPECIES CONCEPT • IDENTIFIES SPECIES IN TERMS OF ECOLOGICAL NICHES

  4. THE ORIGIN OF SPECIES • REPRODUCTIVE BARRIERS KEEP SPECIES SEPARATE • A BIOLOGICAL FEATURE OF THE ORGANISMS THEMSELVES TO PREVENT POPULATIONS BELONGING TO CLOSELY RELATED SPECIES FROM INTERBREEDING EVEN WHEN RANGES OVERLAP

  5. THE ORIGIN OF SPECIES • REPRODUCTIVE BARRIERS

  6. THE ORIGIN OF SPECIES • REPRODUCTIVE BARRIERS

  7. THE ORIGIN OF SPECIES • WHY DO THESE REPRODUCTIVE BARRIERS ARISE? • GEOGRAPHIC ISOLATION CAN LEAD TO SPECIATION • ALLOPATRIC SPECIATION GENE FLOW IS BLOCKED BY THE EXISTENCE OF A GEOGRAPHIC BARRIER

  8. THE ORIGIN OF SPECIES • ALLOPATRIC SPECIATION EXPERIMENT

  9. THE ORIGIN OF SPECIES • ISLANDS ARE LIVING LABORATORIES FOR SPECIATION • ADAPTIVE RADIATION  THE EMERGENCEOF NUMEROUS SPECIES FROM A COMMON ANCENSTOR INTRODUCTED TO NEW AND DIVERSE ENVIRONMENTS

  10. THE ORIGIN OF SPECIES • WHY DO THESE REPRODUCTIVE BARRIERS ARISE? • REPRODUCTIVE ISOLATION CAN LEAD TO SPECIATION (OVERLAPPING GEOGRAPHY) • SYMPATRIC SPECIATION  REPRODUCTIVE ISOLATION DEVELOPS AND NEW SPECIES ARISE WITHOUT GEOGRAPHIC SEPARATION

  11. THE ORIGIN OF SPECIES • SYMPATRIC SPECIATION • TYPICALLY THE RESULT OF SOME GENETIC CHANGE (I.E. POLYPLOIDY)

  12. THE ORIGIN OF SPECIES • AS ORGANISMS BECOME MORE ISOLATED (GEOGRAPHICALLY OR REPRODUCTIVELY) THE BARRIERS BETWEEN THEM INTENSIFY • THIS EVENTUALLY IN RESULTS IN ORGANISMS THAT ARE SEPARATE SPECIES, AND CONTINUE ON SEPARATE EVOLUTIONARY PATHS • HOWEVER; THE RATE OF THIS CHANGE IS NOT CONSISTENT!!

  13. THE ORIGIN OF SPECIES • RATE OF SPECIATION • GRADUALISM VSPUNCTUATED EQUILIBRIUM • GRADUALISM POPULATIONS EVOLVEDIFFERENCES SLOWLY (GRADUALLY) AS THEYBECOME ADAPTED TO THEIRLOCAL ENVIRONMENT, NEWSPECIES EVOLVE GRADUALLYFROM ANCESTRAL SPECIES • PUNCTUATED EQUILIBRIUM EVOLUTION OCCURS INSPURTS (SHORT, QUICK, LARGE)

  14. THE ORIGIN OF SPECIES • WITH ALL THIS SPECIATION OCCURING, HOW DO WE KEEP TRACK OF ALL THESE DIFFERENT ORGANISMS? • THAT’S WHAT YOU GET TO FIND OUT IF YOU COME BACK TO CLASS!!!

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