Zoe T. Kulik
RESEARCH
Early amniote evolution
The origin of amniotes marks a pivotal transition in vertebrate evolution where terrestrial tetrapods were freed from a life tied to water and began to diversify across the landscape. Early representatives of the stem-mammal lineage reveal the emergence of modern ecological structures, including the first herbivores, and the first large-bodied terrestrial animals. Currently, I am using cutting-edge techniques in 3D bone histology and sub-micron imaging through micro-computed synchrotron tomography to better understand the developmental patterns, ecology, and life histories of these early stem-mammals. By revealing aspects of these animals’ biology, I aim to shed light on the origins of the mammalian lineage that split from reptiles over 320 million years ago.
The evolution of mammalian biology
The synapsid lineage spans over 300 million years and includes a vast array of extinct lineages with different ecologies, physiologies, and life histories. While living mammals are also very ecologically diverse, they all share a homeothermic, endothermic physiology. The timing and pattern of when elevated growth rates, increased metabolic demands, and endothermy arose in the mammalian lineage is a fundamental question in vertebrate biology. I use novel lines of evidence from the bone tissue of deeply nested synapsid groups to investigate how mammalian traits evolved. Bone histology is one of the best and most informative lines of evidence to understand growth patterns in the fossil record and is in turn used as one proxy for physiological capacity. By comparing the bone tissue of different synapsid groups, I aim to understand mammalian physiological evolution
Recovery after the end-Permian mass extinction
The end-Permian mass extinction was the largest mass extinction in Earth history. To understand how lineages survived during the extinction interval and diversified in the Triassic, I study the growth patterns, body size, and inferred lifespans of surviving members of the mammalian stem lineage. Through bone histology and body size comparison of species living at different latitudes across the supercontinent of Pangea, I can discover which populations fared better, lived longer, and reached larger body sizes. From this, we can also understand how lineages were able to adapt to varied post-extinction environments across Pangea.
Ontogenetic changes in bone tissue
I am broadly interested in ground truthing developmental patterns inferred in the fossil record by analyzing the bone histology of living animals. These include size/age correlations and investigating variation in growth across the skeleton.
The process of fossilization at fine scales
Taphonomy is the study of how bones enter the fossil record. This process occurs at the microscopic level where original material is either replaced or encased by mineral growth. I am interested in how fossil thin sections can open new lines of inquiry to understand how bones preserve in fine detail and whether original, organic material is present in the vascular and cellular networks of fossil bone tissues.
Research Support
My research is supported by the following funding sources from grants awarded to me or my collaborators
