Many institutions divide Introductory Biology into Cell/Molecular and Ecology/Evolution semesters. There is some sense to this, in that one scale can be seen as cellular and smaller, the other organismal and larger. However, failing to weave the influences, evidences and implications of evolution into the cell-molecular semester wastes an opportunity to show students through our teaching of these topics how central these ideas are. Further, there are a wonderful molecular examples that represent powerful, approachable proofs and demonstrate to students what they can do if they pick up these tools.
The piecemeal presentation of biology found in most introductory textbooks doesn’t reflect modern thinking about how folks learn, and frankly doesn’t make sense on the face of it. The average textbook starts teaching biology with a summary of all the chemistry that will be needed within the book (despite the fact that some of it [looking at you, pH] won’t appear for another dozen or more chapters, then summarizes all the biomolecules and their roles–a summary of things not yet taught. There must be a better way; read on to see one model using hemoglobin.
(I’m releasing this because it’s pretty dense already, but hope to come back and add more links, info)