I'd like to revisit the common atheist contention that mass extinction is incompatible with divine planning.
i) For starters, suppose we approach this from the standpoint of theistic evolution. I'm decidedly antipathetic towards theistic evolution, but for the sake of argument, let's explore how a theistic evolutionist might field this objection. Consider this an a fortiori argument: if even theistic evolution can field this objection, how much more so a better position.
Suppose you're a theistic evolutionist of the atom-to-Adam variety. Adam is the goal. In order to reach the goal, God employs evolution as the means. It is therefore necessary to run through all the prior stages to get to the desired result.
Now, an atheist would complain that that's a terribly convoluted way to get there. Suppose, though, our theistic evolutionist would appeal to the principle of redundancy in nature. A maple tree produces many seeds. "Helicopters." Most of these fail to germinate. But that doesn't mean they're superfluous. To the contrary, producing so many seeds ups the chances that one or more will germinate.
Dandelion seed dispersal exemplifies the same principle. So does the ratio of sperm to fertilized ova. It's a shotgun approach. Throw enough buckshot at the target in the hopes of hitting the target. A theistic evolutionist might say all those offshoots on the the human evolutionary tree reflect the same principle.
ii) Now let's shift to old-earth creationism (a minore ad maius). It's routinely said that 99+% of all species went extinct. I don't know where that figure comes from. I believe it was popularized by David Raup. Given the fragmentary state of the fossil record, it's hard to see how they could extrapolate to an even approximate estimate. But suppose we play along with that for the sake of argument.
iii) I doubt hardly any scientist who believes mass extinction is incompatible with divine planning believes that all extant and extinct species could coexist. Presumably, they don't think it's possible for all those species to exist side-by-side, at the same time and place. For one thing, wouldn't the competition for food and resources be too great given the sheer density and diversity of species under that scenario?
In addition, species are adapted to their environment, but according to conventional geology, that has undergone great variations in the past. The atmosphere was different at different times. The ratio of oxygen to carbon dioxide and methane fluctuated widely or wildly, due to volcanic activity, photosynthesis, &c.
What is breathable air for one species might be toxic for another. Same thing with the chemistry of the ancient ocean.
On a related note, you have the complex symbiosis between fauna and flora. Certain kinds of animals need certain kinds of plants while certain kinds of plants need certain kinds of animals. Likewise, atmospheric conditions affect plants while plants affect atmospheric conditions. A changing albedo changes conditions under which plants thrive, which, in turn, changes albedo.
Every species couldn't simultaneously exist with every other species, for the existence of a particular species depends on a suitable environment. And you don't simply have different species, but different ecosystems that host different species. They go together.
Suppose God desires a world that exemplifies the principle of plenitude. Maximal diversity. Maximal variation.
But if they can't exist all at once, then some species must be phased out before other species can be phased in. To make room for new species, indeed, to clear the decks for a new ecosystem, mass extinction may be necessary. So God instantiates new species diachronically rather than synchronically. Like elevator stage sets where the old set moves back while the new set moves up.
That scenario is consistent with either theistic evolution or old-earth creationism.
Young-earth creationism rejects the way in which the issue is framed. It attributes mass extinction to the flood and post-diluvial climate change.