PHYLOGENY

Phylogeny is the study of evolutionary relationships. It allows us to consider the “bigger picture” of an individual organism. Through phylogeny, a species (or other sets of taxonomic classification) is positioned regarding their origins and relatedness. Phylogeny thus provides us with a chart through which we can track the arrival and continuation of particular traits, behaviors, or simply organisms altogether.


But what makes T. nutricula distinct? Evolutionarily, where did the process of “transdifferentiation” first appear? How might other animals also come to have at least its partial ability? Transdifferentiation in T. nutricula is unlike that which occurs in any other organism. Miglietta & Lessios (2009), however, are the first to claim that the entirety of its genus – Turritopsis as a whole – could share in this unique life-reversing ability. Although there is yet to be a phylogenetic tracing of transdifferentiation in itself, Miglietta & Lessios (2009) have successfully constructed a phylogenetic map of Turritopsis.

 

phylog_1

A phylogenetic tree of the Turritopsis genus (Miglietta & Lessios, 2009).


Miglietta & Lessios (2009) report an altogether lack of genetic difference between members of the Turritopsis genus. Instead, they noted distinct morphological variations, particularly a range of diversity in the number of tentacles. However, in areas of shared climate, the tentacle counts appeared identical, suggesting that such phenotypic variations are due to minor environmental changes (temperature, salinity, and so on). Miglietta & Lessios (2009) claim that no other differences were found. On the contrary, Schuchert (2004) notes a variety of differences in the morphology of Turritopsis medusae, characterizing two separate localities. American and European medusae are even said to have their own, divergent reproductive techniques. It is only with the eventual investment in further Turritopsis studies that such differing answers as these will be rectified.

 

phylog_2

Schuchert's Turritopsis observations (Schuchert, 2004).