Student Access and Logistical Issues
With the exception of the first video, few comments reported technical issues with accessing the videos and associated homework questions (Fig 3 ). This likely reflects the learning curve on a new style of assignment, as well as the fact that the first video (unlike the others) only required the students to watch the second half, which was confusing for many students to know where to begin the video. All videos had captions and/or transcripts available, though several students requested captions on the first video, apparently unaware of how to access them. Consequently, the instructor showed the students in class how to access captions on YouTube videos and these responses were reduced in subsequent videos.
All videos received comments that students watched the video several times (Fig 3 ). These comments were most numerous in the videos deemed by students to be the most difficult (HW1, HW3 and HW4) and likely reflect students rewatching sections of the video that related to the homework questions. Use of captions and transcripts was also higher in these videos for presumably the same reason. Interestingly, a small number of students noted that they watched the videos from Homework 7 (Finding Tiktaalik and The Origin of Birds) multiple times for their own enjoyment and to share with friends or relatives.