Question

question 12 of 17 > the pacific sea otter was hunted to near extinction in the early 1900s. the loss of this predator resulted in several changes to the kelp forest ecosystem. populations of sea urchins, which are one of the sea otters favorite prey, grew to historically high numbers. sea urchins graze on kelp, and the extremely large populations of sea urchins significantly reduced kelp biomass. researchers have hypothesized that overgrazing of kelp by urchins may have hastened the extinction of the stellers sea cow, which also depended on kelp as a food source. identify the ecosystem relationships that were disrupted in the kelp forests by the loss of sea otters. bottom - up regulation by sea otters predation of sea urchins interspecific competition between sea urchins and stellers sea cows mutualism between stellers sea cows and sea urchins grazing of kelp by sea urchins

Explanation:

The sea otters preyed on sea urchins. Without sea otters, sea urchin populations grew, over - grazing kelp which affected Steller's sea cows that also relied on kelp. Bottom - up regulation is not correct as sea otters are top predators here. Mutualism is incorrect as sea urchins and Steller's sea cows compete for kelp. Grazing of kelp by sea urchins is a natural process not disrupted by sea otter loss directly. The main disrupted relationship is the predation of sea urchins by sea otters and the interspecific competition between sea urchins and Steller's sea cows for kelp.

Answer:

predation of sea urchins
interspecific competition between sea urchins and Steller's sea cows