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.
Opsin
Opsin mutates; color vision happens!
Just a brief update to indicate that the opsin function and evolution module is up in its initial-release form here:
Opsin: How mutations add functionality
The heart of this module is interactive software that lets students ‘mutate’ the gene sequence for the human red-sensing opsin protein and discover how easily it becomes a green-sensing opsin… recapitulating the evolutionary ‘re-discovery’ of this ability in old-world primates.
Posted material doesn’t cover the critical step of gene duplication yet; provided references are primarily raw materials for investigating how mutation can lead to altered function. In this case, that means how a green-detecting opsin is simply a red-detecting opsin with some mistakes in it.