What was the purpose of a cat before it was a predator?
Did the entire class of predators come into existence when Adam sinned?
But, sorry, the notion that snake venom and the entire system to deliver it, along with the instinct to use it and to be a predator came into existence when Adam ate the fruit is just plain silly.
This type of stuff makes anybody who believes in God or Creation look really, really stupid, IMO.
YMMV
“This type of stuff makes anybody who believes in God or Creation look really, really stupid, IMO.”
Well, I think that saying you believe in God, but refusing to believe what He tells you in the Bible makes you look pretty stupid, but that’s just me. A supernatural deity creating us is already an extraordinary proposition, compared to that, the rest of what the Bible asserts is pedestrian in comparison.
The other way to see it is, as St. Augustine says with the thorns and thistles, that these injurious organisms were created in the beginning with everything else, but would not have harmed man who retained his original innocence. In other words, the poison and the thorn have their own purpose in the will of God which is intrinsically good, and it's only because of man's Fall that man *experiences* them as harmful.
Many poisons, after all, can be medicinal if used properly. Many noxious plants have very useful other properties. And animal death is not an intrinsic evil. As Augustine says
"One might ask why brute beasts inflict injury on one another, for there is no sin in them for which this could be a punishment, and they cannot acquire any virtue by such a trial. The answer, of course, is that one animal is the nourishment of another. To wish that it were otherwise would not be reasonable.....Indeed this struggle for life that goes on in the lower order of creation does but admonish man for his own welfare to see how resolutely he must struggle for that spiritual and everlasting life by which he excels all the brute beasts."The Fall did not, generally, change the natures of animals and plants. It changed man's relation to those natures.