Explain why allopatric speciation would be less likely on an island close to a mainland than on a more isolated island.

Verified step by step guidance

1. Understand the concept of allopatric speciation: Allopatric speciation occurs when populations of a species become geographically isolated from each other, preventing gene flow between them. Over time, genetic differences accumulate, leading to the emergence of new species.
2. Consider the geographical proximity of the island to the mainland: An island close to a mainland allows for easier and more frequent opportunities for individuals to migrate between the island and the mainland. This migration can maintain gene flow between the populations.
3. Analyze the impact of gene flow on speciation: Continuous gene flow between the island and mainland populations can hinder the genetic divergence necessary for speciation. The genetic mixing keeps the populations similar, reducing the likelihood of developing distinct characteristics that define separate species.
4. Compare with a more isolated island: On a more isolated island, the geographical barrier is greater, making migration and gene flow between the island and any other landmass much less likely. This isolation helps in accumulating genetic differences without being diluted by incoming genes from other populations.
5. Conclude the influence of isolation on speciation: Greater isolation (as seen in more distant islands) typically increases the likelihood of allopatric speciation because it effectively prevents gene flow, allowing populations to diverge genetically and eventually form new species.