After reading the paragraphs below, answer the questions that follow.
Introduced species are a problem all over the world, and there are many examples in the United States. Several years ago, a fisherman caught a northern snakehead fish in a pond in Crofton, Maryland (a suburb of Washington, DC). It was suspected that the fish in the Crofton pond were purchased locally and then intentionally released. Snakeheads are top predators, and 90% of the northern snakeheads' diet consists of other fishes. The northern snakehead can breathe out of water and travel short distances (about 100 feet) across land. They also breed rapidly. Females can lay more than 100,000 eggs per year. Juveniles have also been identified in the Potomac River and other rivers in Pennsylvania.
When snakeheads enter aquatic ecosystems, biodiversity in these ecosystems would most likely
◦ remain the same, because the snakeheads will merge without problems into established communities.
◦ increase, since another species has been added to the environment.
◦ decrease, since the snakehead will prey on native species.
◦ remain the same, since local species will prey on the snakeheads and remove them.
Difficulties in applying the morphological species concept
Indicator and umbrella species.
Species currently endangered in Canada include (a) the Burrowing Owl, Athene cunicularia; (b) Taylor
A Crab-eating Macaque, an old world species of monkey native to Southeast Asia
Reading a radiograph.
Physics questions 3 and 5