Darwin’s legacy, of course, ripples throughout the life sciences, in ways that do not need enumeration to those with some background in these fields, and whose intricacies are better explained elsewhere to those without.
However, Darwin Day is observed as much as an act of solidarity against the willfully ignorant by those who love science and the careful regard for the small-t truth that it requires, as for Darwin's own accomplishments.
The scarcity of BS and the impracticality of spin are a huge part of science’s appeal to those who love it; scientists operate in a professional space in which honest misapprehensions eventually come out in the wash, and—unlike politics or religion—intentional lying is a career-ender.
Unsurprisingly, it attracts people who are not good at prevarication.
Unfortunately, they tend to be ill-equipped to compete with the sort of people who are.
“Intelligent design” comes not from research, but from a PR firm, the Discovery Institute, funded by, and working through, would-be theocrats. These people lie for a living, and they’re both good at it and self-righteous about it.
It’s hard for an honest scientist, accustomed to dealing with honest people, to figure out how to fight this crapola. It’s hard for those in a discipline known for reticence and understatement to step up, and explain to whoever needs to hear it that ID etc. is crapola. But every time we blow off a chance to set the record straight, we dishonor Darwin, our science, the people who taught us.
If you’re looking for a place to start, try this: One reason people with no science background tend to think ID and evolution are six of one etc., or that evolution is the equivalent of a religious belief, is that, as with religion, we ask them to take a lot on faith. Those “irreducible complexity” or “fossil gap” shticks sound plausible if you don’t know better. Make ‘em know better.