"Like most mathematicians, he takes the hopeful biologist to the edge of the pond, points out that a good swim will help his work, and then pushes him in and leaves him to drown."-charles elton

Aquatic Research Pond, July 2015


About Rachel

I am currently a CAS Diversity Post Doctoral Fellow in the Integrative Biology Department of Oklahoma State University. I am working within small OK reservoirs, collecting water quality data and measuring the phyto and zooplankton communities in order to better quantify seasonal turnover in old and young reservoirs. I received a PhD in Ecology and Evolutionary Biology under the direction of Dr. Lawrence J. Weider at the University of Oklahoma. My working thesis involved using theory and experimentation to better understand how population structure influences community properties and stability. I am using Daphnia as a model organism, linking their life-history traits to communities through size-distributions.

In other words, I get excited over equations and graphs, while trying to keep myself grounded in real systems.




Hartnett, R.N. (2019). Variation in life-history traits among Daphnia and its relationship to species-level responses to phosphorus limitation. Royal Society of Open Science. 6:  191024. doi: http://dx.doi.org/10.1098/rsos.191024

Other publications and educational resources

Hartnett, R. and Hoefnagels, M. 2019. Collaborative concept mapping in Google Draw. Article 33 In McMahon, K, editor. Tested Studies for Laboratory Teaching. Volume 40. Proceedings of the 40th Conference of the Association for Biology Laboratory Education (ABLE). http://www.ableweb.org/volumes/vol-40/?art=33

Hartnett, R. (2019). Importing Data into R. Make Teaching with R in Undergraduate Biology Less Excruciating, QUBES Educational Resources. doi:10.25334/Q4W161

Hartnett, R. (2019). Sampling Distributions and Null Distributions: two swirl lessons in R. Make Teaching with R in Undergraduate Biology Less Excruciating, QUBES Educational Resources. doi:10.25334/Q4KJ04

Patten, M.A. and R. N. Hartnett. 2014. Residual variance is no cause for alarm. Frontiers in Ecology and the Environment. 12:545-546. pdf

Research interests

Miro spies a Daphnia by Brittany Rae Benson

Miro spies a Daphnia by Brittany Rae Benson

Rachel Hartnett, PhD by Brittany Rae Benson

Rachel Hartnett, PhD by Brittany Rae Benson

Daphnia lumholtzi by Brittany Rae Benson

Daphnia lumholtzi by Brittany Rae Benson

Daphnia in a jar by Brittany Rae Benson

Daphnia in a jar by Brittany Rae Benson

Community stability

Currently organisms are experiencing change at an unprecedented rate. Therefore knowing what traits or functions enhance a community's ability to persist through time, resist environmental change, and be resilient post environmental events are vital to conservation efforts. Genetic variation, species diversity, species connectivity, and other aspects of community properties have been implicated in community persistence and stability.

Linking populations to their communities

Population ecologists tend to focus on a single species, and what elements (e.g. food abundance, predation) affect growth and reproduction. On the other end of the spectrum, community ecologists focus on how the ecosystem functions as a whole. Individual variation and population dynamics are often overlooked in community and ecosystem ecology. My research strives to unify population and community approaches in order to understand a population within its community. It aims to help predict changes in population demography by understanding mechanisms governing life-history dynamics.

Resting eggs

Resting eggs are produced by many zooplankton species under stressful environmental conditions and are protected by a tough chitinous casing. These resting eggs allow for dispersal between water bodies (e.g. Daphnia lumholtzi has been particularly effective using their resting eggs to invade new systems). They can also be used to resurrect individuals that were produced hundreds of years ago, allowing for a unique opportunity to study microevolution.

Species diversity

Biodiversity, commonly measured by species richness, is the cornerstone of ecological research. Another metric of biodiversity that may play a role in community function is species evenness. Species evenness measures the proportions of relative species abundance to community abundance. A meta-analysis of aquatic ecosystems has shown little to no correlation between species richness and species evenness, indicating that species evenness is an independent axis of biodiversity. Species evenness may play large roles in community properties such as persistence, resilience, and resistance in the face of environmental change.

Current Course Offering(s)

Experimental Design and Analysis in Biology. Spring 2020.

  • Course materials from Spring 2019.

  • Learning R with Swirl. Lessons that I have developed as well as other useful lessons be found here under the QUBES Open Educational Resources.

  • Textbook resources can be found here.

Previous Course Offerings and Available Materials

Introduction to Quantitative Biology, OU. Textbook resources can be found here

Concepts in Biology, OU. Current information by Mariëlle Hoefnagels can be found here

Limnology and Oceanography, UT Austin. 

Introduction to Genetics II, UT Austin.


For students

my mentoring philosophy

I firmly believe that good mentoring takes empathy as well as objectivity. My main goals in mentoring students are to 1) assess and adjust to student needs, 2) provide information and resources to achieve learning goals, and 3) support individual students to help them get to where they want to go. Strong mentorship led to my choice to have a career in STEM, and their modeling as professionals and people was instrumental for me. I hope I can provide similar opportunities for others.

students can expect me:

  • To take different learning styles, personalities, educational backgrounds, etc. into account and actively work on personalizing my mentoring style to best meet an individual's needs.

  • To use inclusive teaching practices and to stay proactive about identifying and addressing my own biases.

  • To foster their career aspirations. At the end of the day, each student wants to end up with the skills and education to land THE job.

  • To reinforce their understanding of experimental design and statistics, as well as develop technical skills in data analysis.

I expect students:

  • To let me know when they need help.

  • To make time to meet for individualized attention.

  • To engage in problem solving under my guidance, rather than expecting me to lay out the answer for them.

  • To self-pace themselves--leaving room for feedback from me and other mentors.

student resources

For OSU students, here are some potentially helpful resources: