Gene flow Knowledge-Based Practice

Questions

1. 1.

   Wildlife corridors are frequently established between isolated habitat fragments to restore gene flow among disconnected subpopulations. Which evolutionary consequence of habitat fragmentation does this restored gene flow primarily counteract?

   • A) The random loss of genetic variation and fixation of alleles caused by genetic drift
   • B) An increase in the baseline mutation rate of nuclear DNA across generations
   • C) The occurrence of directional selection favoring locally advantageous phenotypes
   • D) The development of phenotypic plasticity in response to localized microclimates
2. 2.

   For the physical dispersal of organisms between geographically separated populations to formally constitute evolutionary gene flow, which of the following conditions must be met?

   • A) Migrating individuals must successfully mate and transmit their alleles into the recipient population's gene pool.
   • B) Migrating individuals must completely outcompete and displace the native breeding residents.
   • C) Dispersal between the two populations must occur in equal numbers in both directions simultaneously.
   • D) Migrants must carry brand new alleles generated by spontaneous de novo mutations during transit.
3. 3.

   Persistent gene flow between two adjacent populations inhabiting distinctly different ecological environments most typically results in which outcome?

   • A) Complete cessation of mutation rates within the recipient population
   • B) Immediate reproductive isolation and rapid ecological speciation
   • C) The introduction of maladaptive alleles that counteracts local adaptation
   • D) A substantial increase in the evolutionary impact of genetic drift
4. 4.

   When individuals from a large mainland population migrate and successfully mate within a small, isolated island population, which evolutionary outcome is most likely to occur within the recipient island population?

   • A) An acceleration in the rate of random allele fixation driven by genetic drift
   • B) A permanent cessation of spontaneous germline mutations across all gene loci
   • C) The rapid establishment of complete prezygotic reproductive isolation from the mainland
   • D) An increase in genetic diversity through the introduction of novel or previously lost alleles
5. 5.

   Which of the following best describes the primary evolutionary effect of continuous, high-level gene flow between two neighboring populations of the same species?

   • A) It increases genetic differentiation between the populations, accelerating the rate of speciation.
   • B) It reduces genetic differences between the populations, making their allele frequencies more similar.
   • C) It permanently fixes all dominant alleles in both populations by eliminating non-random mating.
   • D) It completely halts new mutations and prevents future phenotypic variation from arising.

Answers and step-by-step solutions appear after you finish the test.