Why do germs exist and where did they originate from?
Life isn’t “created”, it evolves into a niche where it can be successful. Making humans sick and spreading from human to human is a great niche, as human populations have grown to be quite large. Thus there is quite a bit of competition to be the germs in humans.
There is no true answer. Some scientists believe that viruses are a form of proto life, and were a big part in how the different parts of DNA came together to form the first forms of life on Earth, other “germs” like protozoa, and bacteria. These germs are completely different in nature. Some produce poisonous waste, and others physically feed on us. For example the ones that cause cavities, eat the sugar left behind in our teeth, and their waste is acidic, and weakens the suffice of our teeth. With these simpler forms of life, we’re brought back to the beginning of all life on Earth. While today they maybe different, they are closer related to the beginning, than anyone else that is alive today. So why? One can say that they exist so the whole world can exist.
Germs exist, as most natural things, because they can. That is all that is required for things to exist, the simple ability for them to exist. So they do.
Germs are microorganisms that have existed since the early times of life. The term “germ” is pretty broad, simply referring to microorganisms and typically to those which cause disease. A microorganism is any microscopic organism but mostly refers to bacterium, viruses, or fungus. All three of those are quite different kinds of things, and viruses are even questionably alive.
Bacteria are broadly speaking unicellular organisms which have cell walls but not internal organelles or an organized nucleus. Bacteria were likely the earliest form of life and so they came from where *everything* alive came from. Abiogenesis, the process of the origin of life, isn’t really understood so we can’t be sure how it happened. But bacteria were here from the very beginning and evolved along with everything else to still be around in great quantity today.
Fungus are different in that they have an organized nucleus, and include chitin in their cell walls. The general niche of fungus is decomposition, thriving on the waste products of dead organisms.
Viruses are questionably “organisms” at all, often being simply a protein shell surrounding some RNA molecules. These bits of RNA act as biological instructions that can twist the mechanisms in cells into producing more viruses. They too have been around since the dawn of life, evolving along with living organisms, but many scientists can’t decide if they actually count as living organisms themselves. They don’t eat, they don’t reproduce on their own, they don’t have any senses or response to external stimulus. One way to think of them is the ultimate parasite, one which has outsourced every possible function to the victims it takes advantage of.
In any case all of these “germs” can cause disease by interfering with the biological functions of larger organisms.
Ancient bacteria are the progenitors of all life so actually the question is where did WE come from
Germs exist just like any other life exists. Why do you exist? Why does a fish exist? Why does a tree exist? They exist because they do.
They originated through evolution. They evolved from pervious single celled organisms. The early history of bacteria isn’t well documented having occurred billions of years ago and bacteria and their ancestors didn’t fossilise really well and they tended to look rather alike. There’s evidence of it, it’s just hard to study.
A lot of people tend to think any single celled organism is a germ or bacteria but that’s just not the case.