Speciation

• What is speciation?

  The evolution of a new species from existing species
• What is the process of speciation?

  1. Separation
  2. Different selection pressures
  3. Different allele frequency
  4. No fertile offspring
• How long does speciation take?

  Many generations
• What is allopatric isolation?

  Geographical isolation
• What is geographical isolation?

  Where groups have become physically separated
• What is sympatric isolation?

  Reproductive isolation
• What is reproductive isolation?

  Where there are no physical barriers, but other mechanisms preventing groups from breeding
• What are the six main mechanisms of reproductive isolation?

  • Ecological isolation
  • Temporal isolation
  • Behavioural isolation
  • Morphological isolation
  • Gametic isolation
  • Mating results in hybrid sterility
• What is ecological isolation?

  Habitat differences- monkeys at different heights in the rainforest
• What is temporal isolation?

  Where breeding seasons don't match
• What is behavioural isolation?

  Courtship difference- birds
• What is morphological isolation?

  Different sized genitalia
• What is gametic isolation?

  Gametes do not match (sperm does not survive)
• Why does hybrid sterility happen?

  Homologous pairs of chromosomes cannot be formed