In which of the following scenarios is character displacement most likely to occur?

• A. Two allopatric species that have complete niche overlap.
• B. Two allopatric species that have partial niche overlap.
• C. Two sympatric species that have partial niche overlap.
• D. Two sympatric species that have complete niche overlap.
• E. None of the above.

Answer: (C)

Verified step by step guidance

1. Understand the concept of character displacement: Character displacement refers to the phenomenon where differences among similar species are accentuated in regions where the species co-occur (sympatric) but are minimized or lost where the species' distributions do not overlap (allopatric).
2. Identify the key terms: 'sympatric' means species living in the same geographic area, while 'allopatric' means species living in separate geographic areas. 'Niche overlap' refers to the extent to which species share similar resources or ecological roles.
3. Consider the conditions for character displacement: It is most likely to occur in sympatric species with partial niche overlap because competition for resources can lead to evolutionary changes that reduce overlap and minimize competition.
4. Evaluate the scenarios: Two sympatric species with complete niche overlap would likely face intense competition, potentially leading to competitive exclusion rather than character displacement. Two allopatric species, whether with complete or partial niche overlap, would not experience character displacement because they do not co-occur.
5. Conclude the analysis: The scenario where character displacement is most likely to occur is with two sympatric species that have partial niche overlap, as this allows for evolutionary changes to reduce competition and resource overlap.