Question

How would a food web be affected if a species disappeared from an ecosystem

Answer 1

If one species dies out, then the consumer of that species will die out and then that consumer would die out and so on. Each and every organism is essential in the food chain :)

Answer 2

Well, if one of the major species, that a certain animal eat disappeared, then it would effect the animal that ate it. Then, if that animal doesnt get fed, or eat the right things, it will die, and so will the animal that eats it. Its like the domino effect, if one goes down, so does everything else.
~Hoep this helped :)