Biology faculty

Sara Sybesma Tolsma, Ph.D.

Professor of Biology

Ph.D., Northwestern University
B.A., Northwestern College (Iowa)

VPH 213


Dr. Tolsma’s research efforts in cancer genetics and cell biology have been widely published in scientific journals and have received a number of awards. A Northwestern College alumna, she holds a doctorate in microbiology/immunology/virology. During a sabbatical, she worked on a cell and molecular genetics textbook for non-science majors, as well as an adult Sunday school curriculum on genetic technologies. She has been a part of several symposia on bioethical issues surrounding genetic technologies, such as stem cells, cloning and genetic testing. Her current laboratory research extends her interest in genetics to populations in a study of mayfly genetic variation in Northwest Iowa watersheds. She is the 2015 recipient of Northwestern's annual Teaching Excellence Award.


  • Introduction to the Life Sciences

    Introduction to the Life Sciences

    (4 credits)(IGE option under Science and the Natural World) This course will explore life processes common to plants, animals, and protists; cell structure and function; biodiversity; an introduction to genetics; biochemistry and development; evolution and ecology. Laboratory exercises will help students explore each topic using the scientific method. Hypothesis forming, data analysis and reporting will be essential components of the laboratory. An accompanying text will introduce students to Christian perspectives on current issues in molecular genetics and evolutionary theory. Does not count toward a biology major or minor.
  • First-Year Seminar: Speaking and Writing in Community

    First-Year Seminar: Speaking and Writing in Community

  • Immunology


    (4 credits; alternate years, consult department) The basis of the immune system throughout the animal kingdom is the ability to recognize "self" from "not-self". This course will investigate the molecular and cellular mechanisms that allow organisms to recognize, control and eliminate such not-self entities as bacterial pathogens, foreign tissue grafts and even transformed cells.Prerequisites: BIO115, 116 and CHE101, 102 or CHE111, 112.
  • Introduction to Human Anatomy

    Introduction to Human Anatomy

    (4 credits) An introduction to the anatomical structures of the human body. The focus of the course will be on structures of: cells, tissues, organs and organ systems. The systems studied will include (but not necessarily limited to) integument, bone, skeletal system (including joints), muscle, cardiovascular, nervous, lymphatic, endocrine, respiratory, renal, reproductive and gastrointestinal. Concurrent requisite: CHE101 or 111.
  • Genetics


    An introduction to the principles of heredity and their practical application.Prerequisites: BIO115 or 116.(4 credits)
  • Cell Biology

    Cell Biology

    A study of the structure and function of cells and of their subcellular organelles. Structural detail will be described to the level of macromolecular assemblages. Wherever possible, function will be described in terms of the molecular mechanisms that underlie biological processes. Prerequisites: BIO115, 116, and CHE101, 102, or CHE111, 112 (4 credits; alternate years, consult department)

Publications and presentations

  • Tolsma, S.S., Stem cells, Cloning, GMOs : Learning and Dialoging in the Church about Genetic Techologies, in progress.
  • Tolsma, S.S., L. Furlong, J. Locker, B. Wieking, J. Kleinhesselink, L. Levion, J. Parsons. "Assessing the Genetic Relationship Between Mayfly (Baetis) Populations," Iowa Academy of Science Meeting, April 2010.
  • Tolsma, S.S. “Stem Cells: What Are They; Where Do They Come From; And Why Are They Important?” Putting Science in its Place: Discovery and Responsibility, 22nd Annual Critical Issues Symposium, Hope College, Holland, MI, October 2003.
  • Eppinga, R. and Tolsma, S.S., "Determination of the Mechanism of Increased Capillary Density in Endurance-trained Skeletal Muscle", Iowa State Symposium on the Cell Cycle, April 1997.
  • Tolsma, S.S., Volpert, O.V., Good, D.J., Polverini, P.J., Frazier, W.F., and Bouck, N., "Peptides Derived from Two Separate Domains of the Matrix Protein Thrombospondin-1 have Anti-angiogenic Activity", J. Cell Bio., 122:497-511, 1993.

Professional involvements and accomplishments

  • Member, Christian Action Commission, Reformed Church in America, 1999-2005.
  • Member, New Brunswick Theological Seminary Board of Directors, 2007-present.
  • Member, Sioux County Environmental Initiative Steering Committee, 2008-present.
  • Chair, Societal Issues Committee for the Iowa Academy of Science. 2009-present.


  • Iowa Academy of Science
  • American Scientific Affiliation


  • Teaching Excellence Award, Northwestern College, 2015
  • Sabbatical leave, 2003-04
  • Teaching Excellence Award finalist, 2001
  • Gramm Travel Fellowship Award, Robert Lurie Cancer Center, Northwestern University, 1994
  • National Student Research Forum, Northwesern University student representative, 1994