LUCA[1] almost certainly didn't care about day/night cycles, so it seems accurate. And even if it had, the ways in which a modern mammal with a central nervous

LUCA[1] almost certainly didn't care about day/night cycles, so it seems accurate. And even if it had, the ways in which a modern mammal with a central nervous system cares are new changes brought on by the day-night cycle. An organism if an organism is changing in ways that are caused by the a specific environment, it's still adapting to the environment even if the environment isn't continuing to change. [1]https://en.wikipedia.org/wiki/Last_universal_common_ancestor https://en.wikipedia.org/wiki/Last_universal_common_ancestor