Rate of Speciation

• Rate of Speciation: The rate at which a species becomes isolated and diverges into new species.
• Phyletic gradualism is the accumulation process of periodic changes in the gene pool over long period of time

  • Population diverge slowly = accumulates adaptive characteristics in response to selection pressure and natural selection
• What is species evolved by phyletic gradualism?

  • Transitional forms will be present in fossil record
• Main idea of Phyletic Speciation is that species can evolve over a long period of time (millions) and leads to gradual transition from one form to another.
• • Phyletic Isolation usually have two lineage over a long period of time. Parent and New specie
• Punctuated equilibrium falls under the idea of what?

  • Instant speciation or polyploidy
• Punctuated equilibrium occurs in a long period of stasis (relative stability) where no evolution is occurring but there is a rapid period of change.
• What happens in punctuated equilibrium when no evolution is occurring?

  Mutation is still occurring

  No great variant / allele is selected for due to similar environment condition.
• Fossil records show evidence of punctuated evolution
• How does fossil record show evidence of punctuated equilibrium?

  • When we see long periods of the same form being selected for during stasis
  • Followed by suddenly seeing new forms/ species in the fossil record resulting from diverse selection pressures
• What does it mean by diverse selection pressures?

  Rapidly select for a change in form, so mutations that offered a different trait where selected for