Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Ronald G. Good


A high school Biology II classroom was observed daily in order to study students' conceptual change in evolution of life. The conceptual frameworks of four student participants were documented and the patterns of conceptual change were studied closely throughout the full school year. Data collected included open-ended and structured individual interviews, student journals, daily classroom observations, field notes, and pre-and posttests. All 68 student interviews (17 per student) were recorded, transcribed, coded, and sorted to find patterns of conceptual change. Additional interviews were conducted with the teacher, parents, principal, and high school counselor. The researchers' interpretations were shared with the student participants and teacher to ensure that the voices of all research participants were heard. The finding of this multicase study of conceptual change include: (1) Conceptual change about evolution of life can occur in one of three patterns: (a) holistic, (b) fragmented and gradual, and (c) dual constructions. (2) Conceptual change can occur with little corresponding change in belief. The Darwinian theory of the evolution of life, in its modern form, can be understood but not accepted. (3) The most influential factor inhibiting conceptual change toward a more scientific framework is not belief, but the learner's feelings of disturbance and conflict as learning occurs. (4) Certain critical issues, called threshold questions in this study, seem to be central to conceptual change. An example threshold question is "How could two different species stem from one original species?" (5) Conceptual change is often based upon the idiosyncratic, extra-logical assessment of competing conceptions. (6) Often, the change of one conception allows a sequence of changes to occur in the learner's overall conceptual framework. Overall, this study demonstrates that many conceptions in this area are closely interwoven, so that a change in one conception requires a gradual blending and modification of related conceptions. (7) The actions of a learner's conceptual ecology are found to vary with each individual. The participant's orientation toward academic work, epistemological approach to scientific knowledge, belief in evolutionary theory, and approach to scientific topics play integrated roles in controlling the learning that may occur.