The developmental renaissance in adaptationism.

Area of Science:

• Evolutionary Biology
• Developmental Biology
• Morphological Evolution

Background:

• Unoccupied areas of morphological space are often assumed to be empty due to low fitness and negative selection.
• This assumption is circular: emptiness is explained by low fitness, and low fitness is inferred from emptiness.
• Non-adaptive factors, like developmental constraints, can also explain empty morphospace.

Purpose of the Study:

• To investigate the causes of empty morphospace by examining developmental processes.
• To test whether unobserved phenotypes can be readily produced by development, challenging the assumption of selection-driven emptiness.
• To integrate developmental approaches into the study of adaptation.

Main Methods:

• Studying ontogeny (the development of organisms).
• Employing techniques such as embryology, artificial selection, and comparative methods.
• Examining the developmental capacity to produce morphologies in previously unoccupied areas of trait space.

Main Results:

• Evidence suggests that morphologies in empty morphospace can often be readily produced during development.
• This finding challenges the inference that empty space is solely due to negative selection.
• The results support adaptive hypotheses by demonstrating developmental potential.

Conclusions:

• The study highlights the importance of developmental processes in understanding evolutionary patterns.
• It marks a resurgence of developmental biology in adaptationist research.
• Investigating ontogeny provides a robust method for distinguishing between adaptive and non-adaptive explanations for evolutionary patterns.