Predator, earth was a very dangerous place for a very long time, predator are both prey and predator, survival of the fittest
Technically speaking, they’d come about in exactly the same moment. In practice, I expect the predator-prey relationship would have developed over a long period of time and could have come about in various ways. Maybe starting with opportunistic scavengers, developing the ability to finish of the weak and dying, going on to become true hunting animals or maybe defensive abilities to kill other animals becoming used more offensively under shifting environmental pressures of lack of food or living space.
The first replicators would have been microscopic, unicellular creatures gathering sustenance from naturally occurring minerals, most likely in the water or in tide pools. It would have taken a long long time for the first unicellular creature to evolve that ate other unicellular creatures for its sustenance rather than naturally occurring minerals. So then the question becomes do you define the original creatures "prey" before there's a "predator"? Or do they occur simultaneously, predator evolves, turning the other creatures into prey? Once that first predator "ate" the first prey, the race that continues to this day between the eater and the eaten began.
Science has already shown this. The first evolutionary species fed on itself to multiply. So the answer is both and none.
If you review evolutionary theory, you will find that monads developed first before multicellular life. It is logical to conclude that the monad plants (organisms without motion) preceded the monad plant eaters, and then the monad predators followed thereafter. A plant eater would have evolved into an animal eater. There is no other logical philosophical way for this to happen.
The first predator decided to go on a hunt, before it found the first prey. I say the predator. Anything else before that was scavenged. UNLESS... Something accidentally killed something one day and then shortly after the event decided 'I am hungry, I am going to eat that' before then concluding 'I liked that, I am going to do that again' - NO. This just doesn't happen, I'm still going with predator on this one. Something got hungry and wanted to eat something else.
I guess when one becomes the prey might come after one looking for prey. So something's not even the prey yet, however, there is a predator looking.
You can't be a prey without having a predator. You're a prey in relationship of another animal. For instance we tend to consider cats as predator even if bigger animals prey on them. Even huge predator end to be preyed by parasites. Before being preyed, the prey is just a being. To take an example, let's take the relation of slave and master. Before the slave is made a slave, would he be inherently a slave ? No he would just be a human being.
Yes by the way, my point is just as prey and predator is a relation and without that relation, none are anything. You're probably right on bacterias, I'm not an expert on bacterias.
I was just pointing out they don't have to be different creatures. Your same argument goes the other way though. Before something can be a predator, there has to be a prey.