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During the evolution of multicellularity, the unit of selection transitions from that of the single cell to that of the integrated multicellular organism. Cellular specialization mediates this transition, as the evolution of differentiated cell types leads to fitness becoming a property of the multicellular organism. How does cellular specialization evolve? While we know that genetic changes result in the development of new cell types, it remains unclear whether the development of a new cell type can be ancestrally plastic prior to coming under developmental-genetic control via genetic assimilation. We use the volvocine green algae as a model system to address the overarching question of whether the plastic development of a new cell type preceded its fixation via genetic assimilation. Previous research on the evolution of cellular differentiation in this clade has determined that a gene necessary for somatic cell development is present in species with and without soma and that an ancestral stress response was co-opted during the evolution of somatic differentiation. This raises the possibility that somatic cells may have originated as a plastic trait prior to coming under developmental-genetic control. Here, I show that Eudorina species previously characterized as undifferentiated develop a small proportion of cells resembling soma following exposure to cold shock, an environmental stressor. We also find that the offspring of cold-shocked colonies (but not the grand-offspring) also develop somatic-like cells. We show that these cells are morphologically consistent with the somatic cells seen in closely related species that are obligately differentiated. We find that somatic-like cells in cold-shocked colonies are controlled by cell-level, temporal regulation while the production of somatic-like cells in the offspring of cold-shocked colonies are controlled by group-level, developmental regulation induced by the maternal environment. We propose that cell-level contro

The unparalleled rate at which biodiversity is disappearing around the globe has made conservation of imperiled populations an urgent but difficult task. Critical resources are increasingly limited, constraining effective conservation practices. Genetic distinctiveness is an important metric used to prioritize conservation efforts. The masked bobwhite (Colinus virginianus ridgwayi) is a peripheral population and genetically differentiated subspecies of the northern bobwhite. To generate data beneficial to conservation efforts for the endangered masked bobwhite, I used genomic sequencing methods to resolve fine scale evolutionary relationships among the masked bobwhite, Texas bobwhite, and Mexican subspecies of northern bobwhite. I analyzed thousands of single nucleotide polymorphisms (SNPs) to elucidate genetic diversity patterns and population structure among subspecies, and I applied a maximum entropy approach to generate species distribution models (SDMs) to assess climate variables that affect the geographic distributions, to examine similarity among key subspecies’ habitats, and to project potential habitat suitability of key subspecies under present-day and future climate change scenarios. The results from this study suggest that C. v. ridgwayi, C. v texanus, and C. v. graysoni are more closely related to each other than to other Mexican subspecies and support the genetic distinctiveness of C. v. ridgwayi. SNP analyses suggest some genetic distinction between contemporary and historical samples of the masked bobwhite, which should be further explored since results rely on only one successful historical sample. SDM analyses to estimate climatic variables most important to current and future habitat quality for northern bobwhite showed that specific climate variables that contribute to current and future potential distribution of the northern bobwhite differ when modeling distribution at the species- versus subspecies-level. Also, the distribution of C. v. ridgw