by MeeHumans are on top of their food chain, e.g. phytoplankton -> zooplankton -> mackerel -> tuna -> human, bears are on the top of theirs (same as before but tuna -> bear). On a food chain involving both species, bear would be above since humans don't eat bears.
Fun fact: humans are nothing but a liability for nature as they provide little to no advantages and it could self-regulate without them just fine.
Ok I will break this down:
Well, given the assumption that one judges position by distinction of predator
and prey, humans would be at the top of the food chain, as we have no direct
competition from any predators. However, if we look at it from the point of
whether we are "immune" from being fed upon, the answer is no.To explain
this further, if we go into shark-infested waters without the protection of a
shark cage or (as proven by Mythbusters recently) dolphins, there is a good
chance that we will become the prey and, thus, be demoted from the top position
in the food chain. Further, if you want to take this to another extreme, if one
eats contaminated food and becomes infected with parasites such as tapeworms,
one could see that as a potential demotion as well.In my opinion, we are
at the top of the food chain (or food web if one wishes to use the alternate
concept) since we have the capability to attack any other form of life (whether
single-celled organism or brain-bearing animal) or defend ourselves against it
effectively due to our ability to use tools (including medicines).