A total of five homework assignments and a single paper are due on the dates indicated in the Course Schedule.
Homework Assignment #2 consists of several essay questions in response to a brief newspaper excerpt.
Read the excerpt, given below, from an article from CNN news, posted October 19, 1998, and answer the three questions that follow the excerpt (you can use your textbook Environmental Science or the Internet to find answers to these questions).
Killer whales have been eating an unprecedented amount of sea otters in the absence of their traditional food source of Stellar sea lions and harbor seals in western Alaskan waters, researchers reported. The researchers calculated that a killer whale on a steady diet of sea otters could consume as many as 1,825 otters in a year. How many killer whales exist in the Aleutian archipelago is unknown, but as few as four whales on an exclusive otter diet could cause the declines that have occurred.
The sea otter is a keystone species of coastal ecosystems. As the top predator in a food web having a three-level system (sea otter, sea urchin and kelp) the sea otter feeds on the sea urchin, a plant-eating animal that in turn feeds on seaweed, or kelp. Without sea otters as predators, sea urchins increase in numbers and devour the kelp forests. In contrast, the killer whale is a top predator in the oceanic ecosystems. By shifting to the sea otter as a food source, the whale makes a fourth level in the sea otter's coastal system and upsets the balance in the coastal food web.