Why are some wild berries poisonous? I mean, think about it. Berries live in a symbiotic relation with the animals that help propagate them by eating them and scattering the seeds. I realize that they are not poisonous to all animals. But wouldn’t there be an evolutionary advantage to having more than one small group of animals eat them and spread their seeds?
It’s not always beneficial for the seeds to be eaten. Many plants rely on animals to help spread their seeds, but not *all[/a] animals. A good example of this is hot peppers. They may not be poisonous, but they illustrate the point very well:
They’re “hot” to all mammals (I don’t know about reptiles), but not to birds. Why? Because their seeds are digested in mammals. Maybe not fully digested, but certainly enough to prevent them from taking root and sprouting new plants. However, the seeds pass right through a bird’s digestive system unharmed, so birds are ideal spreaders of the seeds. Thus, sometimes it’s good to get eaten, but not in all cases. Berries which are poisonous to all animals have developed other effective ways of spreading seeds, so getting eaten is a bit of a setback instead of means of proliferation.
Hope that helps you.
Dirx