Sympatric speciation Knowledge-Based Download PDF

Questions

1. 1.

   Which of the following represents the primary evolutionary challenge that a population must overcome to undergo sympatric speciation, but which is absent during allopatric speciation?

   • A) The extinction of parental alleles caused by severe environmental catastrophes
   • B) The loss of genetic variation resulting from prolonged demographic bottlenecks
   • C) The homogenizing effect of ongoing gene flow between diverging individuals
   • D) The physical impediment to dispersal created by expanding geographic barriers
2. 2.

   In Lake Victoria, numerous closely related cichlid species have diversified within the same geographic area without physical barriers. Which evolutionary mechanism has served as a primary driver of reproductive isolation among these sympatric populations?

   • A) Allopatric divergence triggered by geological rifting that physically subdivided the lake into isolated micro-basins
   • B) Gametic isolation caused by biochemical incompatibility between eggs and sperm of ancestral morphs
   • C) Mechanical isolation arising from structural divergence in copulatory organs
   • D) Sexual selection driven by female mate choice for distinct male coloration patterns
3. 3.

   In the apple maggot fly (Rhagoletis pomonella), populations feeding on native hawthorn fruits and introduced domesticated apples within the same geographic region have diverged into distinct, reproductively isolated host races. Which mechanism is primarily responsible for initiating sympatric speciation in this scenario?

   • A) Geographic vicariance caused by physical barriers that permanently separate orchards
   • B) Instantaneous reproductive isolation triggered by allopolyploid genome duplication
   • C) Habitat differentiation coupled with temporal isolation in mating and emergence
   • D) Complete behavioral sterility driven by non-reciprocal cytoplasmic incompatibility
4. 4.

   Which of the following best explains why an autotetraploid plant is immediately reproductively isolated from its diploid parental population residing in the same geographic area?

   • A) Mating between tetraploid and diploid individuals produces triploid offspring that are sterile due to uneven chromosome segregation during meiosis.
   • B) Tetraploid individuals are physically separated from the parent population by microgeographic barriers that halt wind pollination.
   • C) Genome duplication alters floral morphology so drastically that insect pollinators completely fail to visit the tetraploid flowers.
   • D) The extra sets of chromosomes prevent mitotic spindle assembly, resulting in the failure of somatic tissue development in tetraploids.
5. 5.

   Which of the following processes can lead to sympatric speciation within a population without any physical separation of geographic ranges?

   • A) Formation of an impassable mountain range dividing an ancestral range
   • B) Colonization of a distant oceanic archipelago by a small mainland flock
   • C) Polyploidy resulting in immediate reproductive isolation within the same habitat
   • D) Gradual drying of a large inland lake into several isolated smaller ponds