Tobias Landberg

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Doctoral Student


Office: BioPharmacy 410
Voice: (860) 486-4158
E-mail: tobias.landberg@uconn.edu
Mailing address:
75 N. Eagleville Road, U-3043
Storrs, CT 06269

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About:

I am currently a PhD candidate in the Ecology & Evolutionary Biology department at the University of Connecticut, Storrs. Co-advisors Drs. Kurt Schwenk & Carl Schlichting head my committee– which also includes Drs. Elizabeth Jockusch and Kentwood Wells.


Hellbender from Lycoming Creek, PA
Spotted salamander larvae: can you guess which one had yolk removed? Photo by Tobias Landberg

Research philosophy:

"Evolutionary-developmental-functional-eco-morphology" was the joke term I coined with my good friend Manny Azizi to cover our interests. In a nutshell, it's about unraveling the mobius strip of how organisms perform their behaviors, how sources of variation affect that performance, and how that performance affects evolution. The three main sources of variation in nature are ontogenetic (or developmental), ecological (or environmental) and phylogenetic (or evolutionary or genetic). Raising one species of animal under different conditions can reveal whether developmental variation is affected by that environment. Raising related species under the same set of different environments can reveal whether their response to the environment has evolved. Together with detailed knowledge of the animals' environments and the results of a variety of performance tests, the adaptive nature of all this variation can be used to interpret evolution.




Dissertation research:

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‎As the above statement shows, my research interests are broad. The goal of my dissertation work is to study how ontogenetic and ecological sources of variation contribute to species level diversity. If we look at salamanders generally, we see that one of the repeated patterns is to incorporate larval features into the adult forms. The general term for this is paedomorphosis. To understand the processes underlying this macroevolutionary pattern, I have turned to the source: salamander larvae. Salamander larvae are surprisingly uniform, at least compared to frog larvae. However, they do vary consistently along one ecological axis. Salamander larvae that live in ponds characteristically have large gills and tail fins while those that live in streams have small gills and tail fins. Not coincidentally, these are some of the same structures that vary across paedomorphic adult salamanders.




Oxygen plasticity:

Gills and tail fins are respiratory organs in amphibians and they are responsive to dissolved oxygen levels. To see how the environment affects these organs, I raised spotted salamanders in high or low oxygen. Not surprisingly, the ones raised in low oxygen developed larger gills and tail fins. Plasticity often comes at a cost– investment in metabolically active tissues could retard growth or development. Surprisingly, those same animals that invested extra energy in respiratory organs also metamorphosed early. In retrospect it looks like this was an adaptive response. That is, low oxygen probably indicates poor water quality and pond drying. Larvae experiencing such conditions in the wild would probably be well served by getting out of the pond before they turn into the proverbial "meadow raisin".



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