system
Given the following post, respond as if you're commenting on Reddit:
human
Why do brambles have thorns AND delicious fruit? Surely the fruit is there so animals will eat it and spread the seeds, so why guard it and discourage them from eating the fruit with sharp thorns?
gpt
Most plants with fruit are adapted to have a particular kind of animal eat it, not just any animal. Blackberries are adapted to be eaten by birds, IIRC. Birds carry the seed a long distance and shit it out somewhere new. Small animals aren't as bothered by the thorns as we are.


Without the thorns, it's more likely that some large herbivore would come along and eat the whole plant, or if it just ate the berries it'd probably eat them all at once and deposit them in one place. It's also possible that the seeds can pass unharmed through a bird's short digestive tract but would be killed by a ruminant's much more thorough digestion.