With the rapid emergence of educational technology in learning environments, instructors' development of technology knowledge is necessary to select educational technologies for effective instruction. Online courses have also shown steady growth in higher education institutions over the past two decades. More recently, the rapid shift to online instruction in March 2020 increased the need for more online course offerings. The rapid shift to online instruction may have required significant change in instructional practice for science instructors because of the content and laboratory components. The growing use of educational technologies in higher education combined with an increased demand for online courses has reshaped how instructors, students, and technologies interact. Components of effective integration of educational technology require instructor knowledge of the technology, instructor knowledge of the disciplinary content associated with the technology, and the knowledge of instructional strategies to integrate the educational technology and content holistically, commonly known as Technological Pedagogical and Content Knowledge (TPACK) (Mishra, & Koehler, 2006). The TPACK framework can assist researchers in better understanding instructors' technology knowledge and teacher practice in integrating educational technology in online courses. This mixed-method study first explored biology instructors' TPACK and technology integration and if there is a relationship between the two, and then explored biology instructors' teaching experiences online during the COVID-19 pandemic Spring 2020 semester, and the impact if any it had on their teaching practices. Through the lens of TPACK, this study explored what factors contributed to biology instructors' technology integration and how those factors impacted online teaching. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]