Given Proposition: The Shark Population has increased. This is assuming that we only base it off of the given food tree, rather than using the food web, which is more factually correct. This means that the sharks in the area can only eat sea otters, and that sea star populations and sea otters can only eat clams.
1) In this case, the shark population increases. This generally means that the sea otter population by itself has increased, suggesting a positive net change within the given food chain. However, with increased shark populations, would mean a damage to the amount of sea otters in the area. This can create an underpopulation of sea otters, which, if sea stars were not a factor, can mean a increase of clam population.
However.
2) Sea stars are a part of the food chain given. Therefore, it can be suggested that while the sea otter population may stabilize and/or diminish, the sea star has no "predator". This means that with the decrease of the sea otter population, the sea star population may actually grow, as the competition for the same source diminishes. Again, with the demand taking over the need, the sea star population may fall once again due to overfeeding, and essentially starvation.
In essence:
Shark Population: Increased
Sea Otter Population: Decreases (is eaten)
Therefore, Clam Population is speculated to increase.
However, the Sea star population would thereby increase due to having more food.
A larger sea star population in which the clam population cannot sustain would collapse, leading to a fall.
Also, due to the smaller amounts of sea otters in the area, the shark population may also see to an decrease of population, as they die from starvation.
The sea otter population would then stabilize when the predatory amounts or less, and their competition collapses.
Of course, there will always be a "food web". Sea otters do not solely rely on clams, neither do sharks solely rely on otters.
~
