selected
Explanation
The comic has a child asking her mother why giraffes have long necks. The mother explains that when you see an outlandish feature like that, it typically has one of two causes: it could be that the trait was selected for (giraffes with longer necks could reach more food and were more likely to survive and reproduce), or there's a second type of cause. A flashback to 2 million years ago shows two early humans encountering a proto-giraffe. One says "How f*** far is it to the neck?" and the other says "I don't know but it's dark and I'm tired. Later morning we'll kill a lizard." -- implying they gave up trying to hunt it.
The joke plays on two types of evolutionary explanation: natural selection (the standard textbook answer about reaching food) and what might be called "predator laziness" -- the idea that some animals survived not because they were actively selected for fitness, but because predators simply couldn't be bothered to deal with them. The giraffe's long neck isn't just good for reaching leaves; it also makes the giraffe an annoyingly difficult animal to kill, so early humans just gave up and went after easier prey.