In modern evolutionary biology (Neo-Darwinism), microevolutionary divergence occurs through a specific sequence of genetic and environmental processes within populations. What is the correct chronological sequence of steps by which genetic drift and natural selection cause evolutionary change in a newly isolated population?
- 1A small sub-population becomes geographically isolated from the ancestral population, establishing a gene pool with non-representative allele frequencies (Founder Effect).
- 2Spontaneous gene mutations occur within the isolated sub-population, introducing novel allele variations into its gene pool.
- 3Random fluctuations in allele frequencies occur across successive generations due to genetic drift acting on the small population size.
- 4Selective pressures in the new environment exert natural selection, causing individuals with favorable phenotypes to achieve higher reproductive success.
- 5Accumulated shifts in gene frequencies over many generations result in genetic divergence and reproductive isolation from the ancestral population.
Answer
The correct chronological sequence begins with geographic isolation and the founder effect, followed by the generation of novel alleles through mutation, random allele shifts via genetic drift, differential reproduction driven by natural selection, and culminates in genetic divergence and reproductive isolation.
The correct order follows the Neo-Darwinian framework: geographic separation creates an isolated gene pool via the founder effect; random gene mutations introduce new alleles; genetic drift alters allele frequencies in the small population; natural selection acts on phenotypic variations to favor adaptive traits; and long-term accumulation of these changes produces complete genetic divergence and reproductive isolation.
Step-by-Step Solution
Key Concept
Modern Evolutionary Theory (Neo-Darwinism) and Mechanisms of Microevolution
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