replicate
Explanation
This comic takes place in a classroom setting where a teacher explains that "the fundamental concept in all of biology is evolution by natural selection." A student asks, "You mean survival of the fittest?" The teacher corrects this common misconception, explaining that the phrase is not "survival of the fittest" — it's more accurately described as differential survival and reproduction based on heritable traits. The technically correct phrasing is that organisms whose traits happen to be well-suited to their environment tend to leave more offspring, not that there's some absolute measure of "fitness."
However, in the final panel, the teacher concedes that the simplified version "does seem to have made good copies of itself," referring to the phrase "survival of the fittest" itself. Someone off-panel exclaims "Son of a bitch."
The joke is a brilliant meta-observation: the phrase "survival of the fittest" is itself an example of the principle it (inaccurately) describes. Despite being a misleading simplification of natural selection, the phrase has replicated and spread far more successfully than the accurate scientific description — it has out-competed the correct version in the cultural landscape. The meme "survival of the fittest" has survived because it is, ironically, the fittest phrase for spreading through human minds — short, catchy, and memorable — even though it poorly represents the actual science. The phrase is its own proof of concept.