Answer and Explanation:
The trophic web is the process of energy transference through a series of organisms, in which every organism feeds on the preceding one and becomes the food for the next one. The first link is an autotroph organism or producer, such as a vegetable, that can synthesize organic matter from inorganic matter. The next links are the consumers: herbivores are primary consumers and feed on producers. Carnivores are secondary consumers and feed on herbivores, and so on. The last links are the decomposers, microorganisms that act on dead animals degrading organic matter.
When one of the links disappears, it affects the superior links as they will not have their food source. The immediately anterior link will be beneficiated, as it will not be eaten by its predator. And finally, as this last link will overgrow, it will consume greater quantities of its food, causing a decrease in its anterior link.
In the exposed example, if salmon gets extinct, the krill population will increase because they won´t be eaten by salmon. As the krill population goes up, phytoplankton will decrease, because more krill will be eating these organisms.
As salmon disappears, the cephalopod population will be affected, because salmon was one of its food sources. As cephalopods are also eaten by the puffins, these last animals will also be affected. The decrease in puffins population means that the rats' population will decrease too, as rats feed on the puffin´s eggs of puffins. Finally, foxes will be affected too, because rat´s population went down.
This is only one path affected by the extinction of the salmon. But all the animals in the trophic chain will be affected.
