Sea otters play an important role in maintaining the kelp forests of the Pacific coast. Otters maintain the sea urchin population, preventing the sea urchins from overgrazing the kelp beds. If the kelp beds are overgrazed, a multitude of other species will decline as a result. Identify the chain of events that could occur if the sea otter population were reduced along the Pacific coast.

Consider aspects such as pharmaceuticals derived from plants, ecotourism, and the role of diverse ecosystems in supporting industries like agriculture and fishing. Include two examples where biodiversity loss has led to a loss of food, resources, or jobs.

Sea otters, Enhydra lutris, are predators of sea urchins, Strongylocentrotus franciscanus. Sea urchins, in turn, feed on kelp. A study was conducted to determine the effect that Enhydra lutris has on kelp biodiversity. To do so, three bays that have had sea otter populations for varying amounts of time were assessed. Two different types of kelp were studied: a perennial kelp, Laminaria groenlandia, and other annual kelps. The results are shown in the graph below. Additional studies have illustrated the importance of sea otter populations in kelp ecosystems. In the absence of sea otters, the ecosystem collapses. What role do sea otters serve in this ecosystem?   a) Keystone species b) Dominant species c) Competitive exclusion d) Obligate species

refer to picture* Describe TWO ways the impact of humans accelerates change in an ecosystem.