Microbial advantages : where to begin ?
Being so very tiny, they naturally need very little food to sustain each unique individual life.
But even if all but only one of those tiny lives dies in a global holocaust , it (without need for any mate from the same species or any mate whatsoever) can quickly rebuild to incredibly huge numbers of unique individuals, in mere days and weeks - their populations can double every ten minutes, at times.
While each microbe is a perfect clone of its ancestor in theory, in practise they all differ slightly as the reproduction of anything, including life, is never near perfect.
Microbial evolution actually seems to favour imperfect reproduction by design, to widen their gene pool.
Microbes turn passivity into a high artform
That they are usually immobile further reduces further the amount of food needed to survive.
They can get away with this kingdom-wide idleness because being basically very tiny balls, their food intake can be by non-energy-requiring (but short distance only) passive diffusion rather than by energy-needing active transport.
Thus they use far less energy in gathering in their food than any other being, further reducing their overall food intake requirement per weight.
In addition, they have learned to slow down as well as speed up reproduction - in dire times they curl up in a little hard ball and sleep for hundreds and thousands of years until more food arrives.
They will eat anything, if they must.
Each individual can't immediately eat everything - the chemical equipment to do so would require lots of material to build and lots of energy to run.
In addition, it would burst their tiny spheres ---- which are required to remain small so that the short distance force of passive diffusion of food molecules still works.
So each species and individuals has only some of the chemical machinery needed to eat strange foods and survive in hostile environs.
Collectively though they have a massive collection.
They then proceed to share this collectively huge number of machines amongst themselves by HGT --- the horizontal gifting of unique genes from microbe to microbe.
Being so small, microbes have been swept up over land and seas by the strong winds and then dropped all over the world ever since life began, quickly spreading the bounty of HGT everywhere.
But even all this won't be enough to reduce their material and energy demands down to a small enough level to survive out the normal hungry conditions of life on Earth.
So they multi task their genes - so that these genes do various food-consuming tasks only when that sort of food is about - they switch their genes' various capabilities on and off with genetic switches.
This is where so many human biologists frack up the equation.
They feel the bacteria, having no arms and legs, ears, eyes, noses, mouths etc are incredibly primitive.
Biologists among the bacteria see things totally differently
The bacteria biologists seem it totally differently.
They see no on/off switches in all our wonderful complex bodies - all need to be kept turned on and fed , all the time.
The real sophistication of any microbe is that all the chemical various machinery inside are only turned on (and in the case of proteins, only grown) when needed.
Turning on a petroleum-eating enzyme only happens when petroleum is about - and the new supply of petroleum is what supplies new energy to this additional bit of energy-consuming machinery.
(In addition, perhaps, the energy-consuming glucose enzyme is turned off, because there is no glucose about to provide it energy.)
Despite our big brains, in any massive global crisis, us great big naked hairless fastidious eating humans will be among the first to starve, freeze or bake to death.
The nimble microbes will briskly shut of and turn over various genetic switches and win --- again ...