Why do the differences between herbivoures, carnivores and omnivores exist?

Question

im doing yet another assignment and ive found the differences, but why are they so different? and why are they made that way?

Answer 1

In terms of what exactly? Do you mean their anatomy, or their behavior? Your question is too general.

Answer 2

It's something that has developed to enable species that seem common to create an individual niche that allows different species to coexist with ample resources.  For instance, in our area we have many species of hawks and falcons and owls.  The latter species are out during the evening, and prey upon nighttime dwelling creatures.  During the day, each of the hawks and falcons have evolved slight differences that allow them to find food differently, though there will be some overlap in many cases.  One hawk may prefer woodlands and have wings and a flight pattern more suitable for flight through heavily wooded areas.  Another may prefer to patrol the open fields.  Sometimes too species will specialize.  In today's world, that usually spells trouble as habitat diminishes.

So, herbivores in high numbers toward the bottom of the food chain provide food for the omnivores and the carnivores.  But even within each group, subtle and not-so-subtle differences allow many species to coexist in the same area and collect enough food to meet their needs.