Understanding natural selection and similarity: Convergent, parallel and repeated evolution

Area of Science:

• Evolutionary Biology
• Genetics
• Natural Selection

Background:

• Parallel and convergent evolution provide strong evidence for natural selection's role in shaping life.
• Inconsistent definitions of these terms cause confusion and obscure the focus on similar adaptive solutions.
• Recent definitions may inadvertently reduce emphasis on the evolution of similar adaptive traits.

Purpose of the Study:

• To examine existing conceptual frameworks and definitions of parallel and convergent evolution.
• To propose a consolidated framework for a clearer understanding of these evolutionary patterns.
• To harmonize parallel and convergent evolution with natural selection and the concept of similarity.

Main Methods:

• Conceptual analysis of definitions and frameworks for parallel and convergent evolution.
• Examination of the role of ancestral phenotypes in distinguishing parallel from convergent evolution.
• Introduction of 'repeated evolution' as a general term for the evolution of similar phenotypes and genotypes.

Main Results:

• Proposes a framework where parallel evolution involves similar ancestral phenotypes, and convergent evolution involves distinct ancestral phenotypes.
• Introduces 'repeated evolution' to encompass the evolution of similar phenotypes, genotypes, and responses to environmental pressures.
• Argues that genetic similarity is significant only when linked to natural selection or specific origins and locations.

Conclusions:

• The proposed framework clarifies the distinction between parallel and convergent evolution based on ancestral phenotypes.
• The term 'repeated evolution' offers a broader scope for similar evolutionary outcomes.
• Emphasizes that genetic similarity's evolutionary importance is tied to natural selection and its mechanisms.