Evolutionary Feeding Biomechanics

How does our food shape how we look and behave?

freshwater ray gnawing on an insect
freshwater ray gnawing on an insect

Why study feeding?

 

Our food gives us the energy that drives our growth & self-repair. The act of getting that food, foraging, has a considerable effect on our fitness, our net reproductive output - nature's currency upon which selection acts.  How well we catch prey, consume prey, and digest it is our performance - and the higher our performance, the more metabolic energy we can bring to bear growing, maturing, and just generally being alive.  Not only for these important reasons - studying how animals feed is just intrinsically fascinating (at least to me) and who doesn't like food, no?  Given the preoccupation animals have with finding their next meal, the question of how our prey shapes our behaviors and appearance has driven my research program over the last several years.  What materials comprise your food?  How do these materials and structures change how animals approach capturing, processing, and digesting these foods?  

Freshwater ray from Guyana
Freshwater ray from Guyana

Why study elasmobranchs?

 

Sharks, skates, rays, & chimaeras (chondrichthyan or cartilaginous fishes) are an amazing group of animals that survived the "test of time."  From their major radiation in the Devonian, cartilaginous fishes have been incredibly successful in the evolutionary game.  Although superficially similar to prehistoric chondrichthyans, modern sharks (neoselachians) are by no means outdated or "primitive."  They are both a window to understanding how and why early fishes were so successful and also a fascinating study system in terms of their unique (in regards to other vertebrates) characteristics, such as their predominantly cartilaginous skeleton, few overall skeletal elements, large size, predatory attributes & behavior, unique morphological & physiological traits (lack of a swim bladder, urea production, serial tooth replacement, the list goes on...).  Understanding evolutionary traits in context is key to understanding how that organism has come to function in its environment, which has direct application to management and ecological interest.

Dasyatis geijskesi - Demerara Estuary 2015
Dasyatis geijskesi - Demerara Estuary 2015

Why study functional morphology?

 

 

Functional morphology, molecular phylogenetics, and biomechanics are all sub-disciplines within biology that can teach us how an organism has adapted or evolved to function within a particular niche or ecosystem - the who, the what, and the when of natural history.  These disciplines provide complementary quantitative means by which scientists can understand how an organism performs a particular task, be it locomotion, feeding, or other behavior - and how augmentation or variation of a particular structure, modulated by behavior - allows that organism to achieve a particular level of fitness in its habitat / niche.  In more general terms, functional morphology allows us to answer (tentatively) how well an organism performs a particular task in relation to other organisms.  This understanding is most frequently applied to evolutionary studies seeking to understand why some groups are more speciose (species rich) than others. 

catchin' rays in Guyana
catchin' rays in Guyana

Why the hell am I studying this?!

 

Pretty early on in my life I realized I was doomed to the existence as some sort of scientist.  Though I went through phases where physics and/or chemistry were a tad more exciting than biology, I finally settled for a life studying, well, life.  It's no wonder that I did go into biology, especially marine science and ichthyology.  Since I was born, my parents had a menagerie of animals in their house, mostly tropical fish but also boring (somewhat) domesticated mammals and exotic birds.  I grew up camping and hiking with my folks across the US, collecting organisms to observe and catalog.  I grew up maintaining enormous fish aquariums at home, along with the regular care of dogs, cats, iguanas, and other animals.  My first job in high school was at a tropical fish store specializing in reef fishes and invertebrates.  At that point, my future was pretty much sealed.

 

Though sharks and rays have always fascinated me, they only recently became an object of interest for me, thanks to my undergraduate adviser, Dan Huber.  Prior to that I was sold on reef fish taxonomy and phylogenetics and even for a short time the ecophysiology of marine algae (!!!).  If any of my upbringing and schooling has taught me anything - it's that the impressive biodiversity of our little tumbling rock in space is truly awe-inspiring.  The extent to which organisms will go to adapt to a particular habitat or behavior is astounding - and always serves as a seemingly limitless source of variation that sates my curiosity.