Unit 5: Week 5: Scientific Viewpoints

Some agricultural experts have introduced nonnative species on purpose to improve the environment.

One, the avian influenza virus, came to the U.S. carried by birds.

The population of some native species has declined because of a few newcomers, but the news is not all bad.

This microbe can cause a serious lung disorder in infected people.

Some scientists identify a pest’s natural enemy and bring in nonnative enemy species, such as insects, to kill the pests.

Many of the dogs and cats we love so much originated in other parts of the world.

The probable reason they got there is that pet owners dumped the snakes in the wild.

For example, the Asian carp, which was introduced unintentionally to the U.S., has been able to thrive in the Mississippi River and now threatens the Great Lakes ecosystem.

However, this can sometimes create unexpected problems.

Invasive species often take over a widespread area and overwhelm native wildlife.