The baffling intelligence of a single cell: The story of E. coli chemotaxis

Indeed.

Biophysics of Computation: Information Processing in Single Neurons challenges this notion, using richly detailed experimental and theoretical findings from cellular biophysics to explain the repertoire of computational functions available to single neurons. The author shows how individual nerve cells can multiply, integrate, or delay synaptic inputs and how information can be encoded in the voltage across the membrane, in the intracellular calcium concentration, or in the timing of individual spikes: https://www.amazon.com/Biophysics-Computation-Information-Co...

Yes, but it's less complex, and it in turn evolved from even simpler forms. The point is a single mutation doesn't need to create a working flagellum from scratch, it just needs to make it from what's already available. Flagella are complex structures that did not arise until after a lot of other things had already developed.

> And my (limited) understanding is that changes that are not useful or helpful would get lost.

This misunderstanding again comes from the distinction between the features and the instructions. If a mutation isn't harmful, it doesn't get reverted and in fact will spread throughout a sizeable fraction of the population. The thing is that without evolutionary pressure as more mutations occur, they will eventually break whatever the original mutation did, so the feature it coded will eventually disappear, though it can take a long time and it may change significantly before it does. There are some caveats though - a gene might code for multiple features, or may exist on a part of the DNA where further mutations are suppressed anyway, and thus even though the feature provides no advantage on its own there will still be evolutionary pressure to preserve the gene, and thus a neutral or even a slightly bad mutation might be retained indefinitely.

> And additional to that, if an organism has a pump (which it needs to function properly) and that pump suddenly is no pump, it's a very bad flagellum, that organism has a very big problem. It's like if we swapped our arms for wings. Wings are cool, but we wouldn't be able to fly anyway, and we'd have serious problems as humans with no arms and hands.

In this particular case, cells have many molecular pumps, so converting some to flagella is not a very big problem. The benefits of a shitty flagellum did outweigh the cost of losing some molecular pumps, but this is a very real limitation to what evolution can produce. Humans certainly won't evolve wings naturally without a lot of other changes happening first. But at the same time wings have evolved - in the case of birds their ancestors evolved an extremely efficient respiratory system more than 100 million years before they took flight, which helped them survive the great dying and subsequently take advantage of the oxygen rich Mesozoic era. Among these a mutation for hollow bones aided agility on the ground, among these adaptations for feathers helped with retaining body heat, among these adaptations for lunging their arms forward helped them grab prey, among these adaptations for tree climbing allowed them to become better ambushers, and it was among these that sacrificing some of their arm capabilities for shitty wings was a net gain.

That said, it is very rare that I hear someone describing themselves as Christian who denies the general 7 day creation story. I happen to personally believe it was seven consecutive days^, but I've heard arguments it could have been seven days with an unknown gap in-between each pair.

^ "day" being the most morally-understandable way of describing the intervals at which the creation occurred. Obviously there was no sun or even light at first, so the concept of a day itself is shaky, and I make no claims as to how many cesium-133 transitions may have occurred in that period, or how far light might have travelled in one of them once it was created, or the magnitude of the various fundamental forces' impact on matter in that period, or really anything related to our understanding of how the dynamics we currently observe may have behaved in those intervals.