system
Given the following post, respond as if you're commenting on Reddit:
human
Why aren't there an excessive amount of fossils right at the KT Boundary?

I would assume (based on the fact that the layer represents the environmental devastation) that a large number of animals died right at that point but fossils seem to appear much earlier, why?
gpt
If a mass extinction occurs over, say, 100 years, there are probably actually fewer deaths during that century than in the previous century. Over the course of any given century, pretty well every animal living at the start will have died. In a stable population, these will be replaced by new births and there will be many generations of roughly consistent deaths and births. But if species are dying out, then halfway through the century, there will have been fewer births to contribute to additional deaths later in the century so by the end of the century there will have been fewer deaths than average, despite every member of the species dying.