Allopatric speciation Knowledge-Based Download PDF

Questions

1. 1.

   Why do small populations that become geographically isolated at the periphery of a species' range typically undergo allopatric speciation more rapidly than large populations split by a vicariant event?

   • A) Peripheral populations experience elevated base-substitution mutation rates that directly create postzygotic barriers.
   • B) Ongoing gene flow from the central population maintains high heterozygosity and prevents inbreeding depression.
   • C) Heightened effects of genetic drift and exposure to novel selective pressures accelerate genetic divergence.
   • D) Strong balancing selection preserves ancestral alleles, enabling rapid adaptation to marginal ecological niches.
2. 2.

   Which of the following events represents an example of allopatric speciation initiated by vicariance rather than dispersal?

   • A) The emergence of a geological rift valley that subdivides a widely distributed terrestrial mammal population into two disjunct groups.
   • B) The trans-oceanic rafting of a small cohort of iguanas on storm debris to colonize an isolated uninhabited island.
   • C) The wind-driven transport of plant seeds across an existing ocean strait to establish an isolated offshore population.
   • D) The accidental transport of a fertilized female lizard across an ancient marine channel to establish a new mainland colony.
3. 3.

   If two geographically separated populations re-establish sympatry following the breakdown of an environmental barrier, which observation demonstrates that allopatric speciation has been completed?

   • A) The two populations occupy distinct ecological niches within the overlapping territory.
   • B) The two populations exhibit noticeable morphological divergence in courtship displays and coloration.
   • C) The two populations are unable to interbreed to produce viable, fertile offspring.
   • D) The two populations actively compete for identical shared nesting and feeding resources.
4. 4.

   Following prolonged geographic separation of two populations, which of the following directly causes the evolution of intrinsic reproductive isolation between them?

   • A) Continuous gene flow maintaining identical allele frequencies between both populations
   • B) Independent genetic divergence driven by natural selection, genetic drift, and mutation
   • C) Immediate phenotypic plasticity that alters behaviors without modifying allele frequencies
   • D) Convergent evolution that stabilizes identical reproductive traits in both environments
5. 5.

   Which of the following processes is a necessary initial requirement for allopatric speciation to occur?

   • A) Physical geographic separation preventing gene flow between populations
   • B) Polyploidy arising spontaneously within individuals sharing the same territory
   • C) Behavioral divergence occurring among individuals inhabiting the same geographic area
   • D) Disruptive natural selection acting on a single population within an undivided range