In search of morphological modules: a systematic review

Area of Science:

• Evolutionary Biology
• Developmental Biology
• Morphology

Background:

• Morphological modularity, arising from semi-independent inheritance, development, and function of body parts, is crucial for understanding organismal evolvability and plasticity.
• Delimiting morphological modules and identifying their origins is a key area of biological research.
• Despite the presumed pervasiveness of modularity, its frequency across different systems and the factors influencing its formation remain unclear.

Purpose of the Study:

• To quantitatively appraise the research landscape of morphological modularity from 1958 to the present.
• To identify what aspects of morphological modularity are studied, the methodologies employed, and how results are explained.
• To reveal trends and gaps in the scientific investigation of morphological modularity.

Main Methods:

• Systematic review of over 200 original research articles on morphological modularity.
• Quantitative analysis of research focus, methodologies, and explanatory factors.
• Examination of studies published from 1958 to the present.

Main Results:

• The study of morphological modularity presents a heterogeneous picture, with certain taxa, systems, and approaches being over-represented in research.
• Significant gaps exist in the investigation of other taxa, systems, and methodological approaches.
• An uneven distribution of research effort and focus was identified across the field.

Conclusions:

• Current research on morphological modularity exhibits significant biases in focus and methodology.
• There is a need to broaden research efforts to understudied areas to gain a comprehensive understanding of morphological modularity.
• This review provides a broad overview of current knowledge and directs future research efforts in morphological modularity.