biology

Dr. Justin McAlister

Assistant Professor

Ph. D., University of North Carolina at Chapel Hill
Marine and Invertebrate Biology

Contact information:

Office: Swords 232
Lab: Swords 216
Phone: 508-793-3417
Email: jmcalist@holycross.edu

Teaching:

Fall 2014 Semester:

 

Spring 2015 Semester:

On research leave.

 

Publications

Research: 

My research interests sit at the interface of functional and population biology and center on three broad questions:

  • How do organisms respond to environmental change?
  • How much variation exists for these responses?
  • How come organisms respond in the way(s) that they do? 

My work is empirical, uses integrative and comparative approaches, occurs in the lab and the field, and I focus primarily on marine invertebrates and their larvae.

I encourage students with interests in marine biology, invertebrate biology, organism-environment interactions, ecotoxicology, "eco-devo", and/or the expression and evolution of phenotypic plasticity to contact me about opportunities in my lab.

My research follows three trajectories:

(I) Phenotype and life history evolution: responses to natural environmental change

My recent research has included examinations of how historical environmental changes in phytoplankton food levels have led to changes in the two primary means by which marine invertebrate larvae acquire and utilize the structural and energetic materials required for metabolism and morphogenesis: (1) by using their own food collection structures to capture exogenous phytoplankton, and/or (2) by utilizing the endogenous biochemical constituents provided to them by their mothers in the egg (the single most important cell in an organism's life cycle).  For these studies, I have been examining the eggs and larvae of tropical echinoderm "geminates," closely related species that were separated ~3.2 million years ago during and subsequent to the rising of the Isthmus of Panama.  These organisms now inhabit marine oceanic environments, the tropical western Atlantic and eastern Pacific, that differ markedly in primary productivity and phytoplankton food availability.  Trans-isthmian geminate species offer a unique replicated natural research system that can be used to examine the ecological and evolutionary ramifications of large-scale environmental changes.

 

 

 

 

   

 

 

 

(II) Population ecotoxicology: responses to anthropogenic environmental change

Although we have some understanding of how individual organisms respond to specific toxins, we know less about the degree of variation in response to toxin(s) within and among organisms and populations.  I am interested in using marine invertebrates and their larvae as model systems to investigate this variation.  Variables of concern to the marine environment include heavy metals (e.g. cadmium and lead), which can affect the deposition of biomineralized structures such as the skeletons and shells of larval invertebrates, and organic hydrocarbons, which can bioaccumulate in larvae and propagate into oceanic and coastal food webs.  Preliminary information suggests that some populations of marine organisms have evolved the ability to tolerate high hydrocarbon loading or exposure to high concentrations of metals.  For adults, these tolerances generally trade-off with other life-history characters, such as fecundity or growth, yet we know very little of the effects, and variation in effect, of anthropogenic toxicants on vulnerable larval and juvenile stages of organisms and populations in marine ecosystems.

   

(III) Ecological developmental biology: Regeneration as a plastic phenotype

Regenerative ability is common among many animals, in particular marine invertebrates, but the degree to which regenerative ability varies among taxa and individuals is unclear.  Although the regulatory mechanisms underlying the regeneration of phenotypic structures are known for some taxa, few studies have examined regenerative ability in an integrative evolutionary context to investigate the balance between selective forces, which maintain this ability, and organismal factors, which constrain its expression.  Similarly, our understanding of how the expression of regenerated structures differs under natural conditions is limited.  In some marine invertebrates (e.g. ophiuroid echinoderms and octocorals), differential patterns of regeneration are environmentally induced, suggesting that regenerated structures, as well as regenerative ability, can be considered distinct plastic phenotypes.

 

 

 

 


Educational Opportunities in the Marine Sciences

I am an alumnus of Sea Education Association's "Sea Semester", an educational program for undergraduate students with interests in oceanography, nautical science, maritime studies, and sail-handling, based in Woods Hole, Massachusetts.  I am also an alumnus of the summer courses offered at the University of Washington's Friday Harbor Labs.  In addition, I have strong ties with the Smithsonian Tropical Research Institute in Panama and the Bermuda Institute of Ocean Sciences in Bermuda.  Please contact me if you have specific interest in the educational and/or research internship programs offered by any of these institutions, or if you're generally interested in off-campus marine education and research opportunities and would like some suggestions.


Publications:

McAlister, J.S. and A.L. Moran. 2013. Effects of variation in egg energy and exogenous food on larval development in congeneric sea urchins. Marine Ecology Progress Series 490: 155-167.
Available at: http://www.int-res.com/abstracts/meps/v490/p155-167/

Moran, A.L., McAlister, J.S., and E.A.G. Whitehill. 2013. Eggs as energy: revisiting the scaling of egg size and energetic content among Echinoderms. Biological Bulletin 224: 184-191. GET PDF

McAlister, J.S. and A.L. Moran. 2012. Relationships among egg size, composition, and energy: A comparative study of geminate sea urchins. PLoSONE 7(7): e41599. doi:10.1371/journal.pone.0041599. GET PDF

Moran, A.L. and J.S. McAlister. 2009. Egg size as a life history character of marine invertebrates: Is it all it’s cracked up to be? Biological Bulletin 216: 226-242.  GET PDF

McAlister, J.S. 2008. Evolutionary responses to environmental heterogeneity in Central American echinoid larvae: plastic versus constant phenotypes. Evolution 62(6): 1358-1372.   GET PDF

McAlister, J.S. 2007. Egg size and the evolution of plasticity in larvae of the echinoid genus Strongylocentrotus. Journal of Experimental Marine Biology and Ecology 352: 306-316.   GET PDF

Allen, J.D. and J.S. McAlister. 2007. Testing rates of planktonic versus benthic predation of larvae in the field. Journal of Experimental Marine Biology and Ecology 347: 77-87.  GET PDF

Podolsky, R.D. and J.S. McAlister. 2005. Developmental plasticity in Macrophiothrix brittlestars: are morphologically convergent larvae also convergently plastic? Biological Bulletin 209(2): 127-138.   GET PDF

Marko, P.B., S.C. Lee, A.M. Rice, J.M. Gramling, T.M. Fitzhenry, J.S. McAlister, G.R. Harper, and A.L. Moran. 2004. Mislabelling of a depleted reef fish. Nature 430: 309-310.   GET PDF

McAlister, J.S. and S.E. Stancyk. 2003. Effects of variable water motion on regeneration of Hemipholis elongata (Echinodermata: Ophiuroidea). Invertebrate Biology 122(2): 166-176.  GET PDF