I think one thing that seems relevant to humans, is we seem to be bothered only once we can relate to the other being in a more explicit way. This is true even between our peers. Maybe as we understand more and more of other creatures so will our empathy.
Particularly good if you're interested in diving in more: https://www.youtube.com/watch?v=c33XPyljUiw
Essentially, bread rises because of the the death throes of tiny, microscopic unicellular fungi.
(And of course, the spring only "sticks" if the dough is both elastic enough to permit that expansion -for example because it has a gluten network- and developed enough that, in that expanded state, the dough can set well enough to support its own shape, rather than deflating once we remove the heat, and the high pressure gasses cool down and contract, pull the now baked bread in on itself)
My impression was that fermentation outside the oven causes most of the rising, with a bit of "oven spring" from the vaporization of water in the dough.
The yeast obviously die in the oven, but I don't think the death per se is critical for the leavening.
But when the drought get hot the tiny bubbles of CO2 expand and when it's too hot and the drought get cooked and the structure around the bubbles is fixed like in a sponge.