Is there a species that is so depedant on humans that it would become extinct if humans became extinct?
Cows?
Sheep?
Alex Chu?
Maize and some flower that grows off the side of cliffs in Hawaii are dependant on humans for fertilization.
how are the flowers fertilized by humans?
Well, cows and sheep were capable of munching grass and making little cows and sheep before man domesticated them, and presumably they could still do so if man didn’t exist.
I think most domesticated animals could revert to their old ways and survive. Some more easily than others, of course.
I mean, even a well-fed, lazy house cat can usually start hunting and killing rodents if it has to. Pigs that have escpaed from farms become successful, feral animals again in short order.
The only animals that would have a hard time are domesticated dogs especially the toy and “frou frou” breeds, many of whom have no survival skills and have never learned to hunt or forage. But the species would not die out. Over time, the dogs with the best instinct for survival would find each other, form packs, and revert to long-forgotten wolf-like behavior. Dogs would still exist a few centuries later… but the pure breeds we know today probably wouldn’t be recognizable any more. No more recognizable bassets, dachshunds, etc. There’d just be some kind of generic mutt.
interesting. how are the flowers fertilized by humans?
Ummmm… maize is pollinated by the wind.
Used car salesmen would bite the dust.
There are various human-specific parasites (mites, lice, worms, even protozoans I believe).
Someone uses mountain climbing gear to reach the flowers. They are on the side of a steep cliff. He collects pollen from the flowers and delivers it to different flowers, using something like a cotton swab, IIRC.
I have forgotten what has happened to the previous pollenators nor do I remember what they were (insects, birds, ?). My local PBS station (KERA, Dallas, TX) used to show a short film about the process and how someone managed to photograph it as a filler when shows ran short, but I haven’t seen it in awhile.
Most domestic varieties are not separate species from their natural counterparts; even if the domesticated versions were wholly dependent on us, their parent species would still probably do just fine (depending on how we got “extincted”).
Only those critters which have so specialized as to make humans their sole food source, or rely on humans exclusively to complete their life cycles, as Mangetout mentioned, would really be in trouble.
I dunno; don’t you think sheep would be in trouble? They’re so slow, so fleecy, so stupid…
Talking birds would no longer talk. 
Of course a great many species would decline in number (or concentration at least); rats, dust mites and silverfish being possible examples (although depending on the exact manner of demise of the human race, the rats might have a party to begin with…)
Barn owls would have to change their name, as would Housemartins.
A lot of animals in zoo would die off…
So animals on their way to extinction would die off without some human interaction.
Some breeds of dogs would die off, not just from hunger but also from weather conditions.
I heard somewhere that some house cats have become completely dependant on humans because of some chemical imbalance or a genetic disorder or something. So they’ll die.
Dolphins will rule the Earth!
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- In one Isaac Asimov trivia book, it’s mentioned that without human help several species of Chinese silkworms would go extinct because they have lost the abiity to fly (due to selective breeding to maximize silk production) and have no other way to protect themselves from predators or flee. Of course, it was human interference that put them in that situation in the first place, so I dunno if that counts exactly…?
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- In one Isaac Asimov trivia book, it’s mentioned that without human help several species of Chinese silkworms would go extinct because they have lost the abiity to fly (due to selective breeding to maximize silk production) and have no other way to protect themselves from predators or flee. Of course, it was human interference that put them in that situation in the first place, so I dunno if that counts exactly…?
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Maize (pretty much any species of corn) would become extinct because it has been domesticated by selective breeding.
The corn which it first came from had curnels which were far apart, making it easy for them to fall and grow. Our ancestors were able to selectively breed the corn to have more curnels on each stalk.
This made it impossible for the corn to fall, it was just too packed together. Corn, as we know it, will die after we’re gone because it can’t spread it’s own seeds. Perhaps a few wild versions of it will survive, but that’s if they’re still in existance (a fact that I don’t know).
Also some forms of lice will become extinct if mankind is gone.
Latest theory I heard is that the wild ancestor of corn is now believed to be teosinte, which still grows wild in Central America. But it’s a lot different than what we call “maize” or “corn”.
Guinea worms will become extinct
So will polio (unless it can infect other primates)
Can’t think of any other entire species that will become extinct without us, but varieties of certain things (such as toy poodles and hairless cats) will disappear.
The ragdoll cat would be history. 
Also, I imagine all species currently on the endangered list wouldn’t make it, especially those who cannot mate in the wild - Giant Pandas, California Sea Otters, Santa Catalina foxes and buffalo, etc.