The Princeton Guide to Ecology

Functional morphology is the study of relationships between morphology and organismal function. A simple inspection of animal diversity reveals a remarkable array of phenotypes and concomitant functions. For example, even within a single mammalian group (bats), one observes organisms consuming food of all types, such as blood, fruit, leaves, nectar, insects, and other animals. Accompanying this diversity in diet is a remarkable diversity in morphological structure ranging from vampire bats with fangs for making sharp incisions for drawing blood to leaf-eaters specialized for grinding and mastication. One also observes similar variation for different kinds of animal locomotion. Whereas some organisms have evolved wings for flight, such as in birds, bats, and flying insects, other species have evolved elongated hindlimbs for running or jumping, such as in some lizards and kangaroos. This diversity in form and function forms an essential template for functional morphologists because it provides the “menu” from which researchers can address how function relates to form.

biomechanics. A subfield of functional morphology that applies mathematical and biophysical theory to understand animal movement

function. The use, action, or mechanical role of phenotypic features

kinematics. Animal movement; the angles, velocities, and rates at which different body parts move throughout space and the study thereof

kinetics. Forces produced by organisms during dynamic movements and the study thereof

morphology. The descriptive features of the external and internal (anatomical) phenotype

performance. A quantitative measure of the ability of an organism to conduct an ecologically relevant task such as sprinting, jumping, or biting

structure. The configuration of muscles, bones, tendons, and other tissues that allow animals to achieve dynamic movements

Functional morphology is inherently mechanistic in that it seeks to understand the basic mechanical principles that explain organismal function. Thus, rather than focus purely on descriptive patterns of organismal function (i.e., the frog jumped 20 cm), functional morphology aims to understand the underlying physiological and morphological principles that allow organisms to conduct physical tasks such as swimming, running, flying, and feeding, among others. In contrast to reductionist research that studies living organisms from the biochemical or biophysical perspective (e.g., cell biology), functional morphology generally focuses on emergent functional properties arising from the whole organism. Whole-organism functional capacities represent the end output from integrated morphological, physiological, and behavioral attributes of organisms, and hence their study requires an integrative approach. For example, cheetahs are known for their remarkable sprinting capacities, and one can study how different aspects of their internal anatomy (i.e., lung and heart function, limb muscular morphology) allow cheetahs to sprint so quickly. However, functional morphology is less focused on functional capacities below the organismal level, such as the effectiveness of an

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