I just killed a little spider and afterwards remembered hearing that they ate bugs. So now I figure I am going to be infested with little ants and flys in my office. It seems that most animals/bugs serve some purpose in our ecosystem.
This got me thinking, what animal(s) can we not live without?
Well, I believe that there are essential bacteria in our guts that we physically can’t live without. Not sure if that counts as an ‘animal’ though.
We can, however, live without mosquitos. DIE DIE DIE
Aren’t mosquitoes a main diet of some bats (and some kinds of fish, oh…frogs too!)?
Cats.
Humans. We can’t live without humans.
Damn, I meant to put a disclaimer “NOT COUNTING HUMANS”.
I’d be really sad if herds of ribeyes or venisons didn’t continue to inhabit the praries. Oh, and bacons too.
I was kind of being sarcastic, but I was under the impression that bats would rather eat other larger insects and only resort to smaller critters like mosquitos when their normal, larger food source is scarce.
The loss of bees might have a very disproportionate effect all the way up the line. They help to pollinate a great many crops.
Biologically speaking, bacteria aren’t animals. They aren’t plants either. They’re bacteria. In a kingdom of their own.
Thanks, I thought that might be the case. 
In all seriousness to your OP, there have been hundreds of species that have recently gone extinct, and thousands of local populations of critters have been decimated. We are still here. I think we could probably live without a great number of species. Not that that would be a good thing, but I think we could cope.
I don’t think there is any one species that humanity is dependent on. Cows can be replaced, horses can be replaced, dogs and cats can be replaced (just not with apes, please). Honeybees are probably the closest though.
nitpick:
I think it is now widely accepted to call bacteria a domain, not a kingdom.
There are literally thousands of species of bees aside from honeybees. When you consider that Australasia, the Americas and most of Asia and Africa managed to get along just fine before honey bees were introduced by humans I can’t see any justification in claiming that there aren’t any replacements for the honey bee.
Worms.
No worms, no topsoil. And the starving, and the dying, and the faving!
Tris
Would there really be no topsoil at all without earthworms? I know they’re important, but they aren’t solely responsible for topsoil, are they?
Anyway, how about blowflies and other carrion-eating insects; their larvae are very important in keeping the world relatively free of decomposing corpses (sure, there are other organisms that join the feast, but the insects do the bulk of it).
They aren’t responsible for it at all. Worms turn soil over, but in most parts of the world insects are more impoirtant in that regard.
That’s a huge group you’ve just named. Almost every insect group I can think of has numeorus carrion feeding members: wasps, flies, beetles, moths, bugs, crickets and so forth. I hardly think that naming an entire functional group is in the spirit of the OP. We might just as well name “all bees and other pollinating insects” or “all plankton eating vertebrates”.
The other question is how long it would actually take for scavenging mites, amphipods, worms birds and so forth to fill the niche. I doubt even the disappearance of such a broad group would have any noticable impact on most people.
Edgar Wallace wrote a story in which a misguided scientist who disliked worms was going to poison them all - and he had to be stopped at all costs.
Wouldn’t Africa be a problem without dung beetles. All those herds of elephants passing … by :eek:
Uh…that cite is from a mosquito-control service, which might view bats as economic competitors. Their text includes a scary warning about rabies too – they don’t want you relying on bats. I question the bias of their claim.
Sailboat