chapter 18 - populations and evolution

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Across
  1. 5. type of speciation - populations become geographically isolated - environmental conditons vary in both regions and are both differently effected by natural selection - formaiton of a new species - no logner interbreed
  2. 7. the idea that organisms in a populations whose phenotypes gives them a selective advantage have a greater probabilty of reproducing
  3. 9. type of natural selection - both extremes favored by selective pressure acting
  4. 11. the evolution of a new species from an already existing one - populations become genetically isolated from one another
  5. 13. isolating mechanism where breeding seasons do not coincide
  6. 15. isolating mechanism where mutation changes the courtship behaviour
  7. 16. isolating mechanism where gametes are prevented from fusing due to bio-chemical incompatability
  8. 18. principle that calculates the frequencies of alleles and genotypes in a population by looking at the number of recessive phenotypes
  9. 19. type of speciation - same area within a population - reproductively isolated - no interbreeeding
  10. 21. changes in allele frew. of a population
Down
  1. 1. an example of genetic drift - catastrophic event occurs to a population resulting in a smaller population for at least one generation - extinction + recovery - disasters are due to chance - alleles lost over-time (baluga whales were once hunted to near extinction but measures to protect them have allowed them to underog recovery)
  2. 2. isolating mechanism where hybrids formed are sterile so cannot produce viable gametes
  3. 3. thicker mucus - damaged lungs - coughing
  4. 4. an example of genetic drift - when a small group fo organisms break away from the original and larger population - migration - isolated - creates a new population with a lower genetic diversity
  5. 6. type of natural selection - one extreme favored
  6. 8. type of natural selection - mean favored
  7. 10. changes in allele freq. due to chance in a small population - not due to selective pressues - leads to alleles being over-expressed or becoming extinct
  8. 12. isolating mechanism where anatomical differences prevent mating from occuring
  9. 14. the number of times an allele occurs within a gene pool
  10. 16. all the alleles of all the genes of all the individuals in a population
  11. 17. isolating mechanism where populations inhabit diff. habitats in the same area
  12. 20. isolating mechanism where populations are isolated by physical barriers