This story is from 2015. Research proposal: How could you find out what has happened since?
Have you noticed that there are fewer butterflies flitting around?
Scientists have measured a steep decline in the number of monarch butterflies that has led the Fish and Wildlife Service to consider adding them on the Endangered Species list. If they do, it would affect laws that govern the herbicides farmers use to kill weeds, which in turn affects the butterflies’ habitat.
The monarch butterfly naturally lives in milkweed, a plant present in fields across the United States. Monarchs in cold areas typically migrate south to areas in Mexico and Texas for the winter; others live year-round in warm habitats.
Deforestation in Mexico, where butterflies migrate during the winter, has contributed to their decline as well as the use of pesticides on U.S. farms.
As a result, monarch butterfly populations have decreased by 90 percent in the past 20 years, a phenomenon that fits with a global pattern of species endangerment, according to environmental groups.
Over 95 percent of all species that have ever lived on Earth since its beginning have become extinct. Most of these occurred in a wave of “mass extinctions,” in which 75 percent of species on earth disappear in a relatively short period of time.
Earth could experience another period of mass extinction by the year 2200, according to a report by Nature magazine. The Center for Biological Diversity has said that mass extinction has already begun, with species currently going extinct at over 1,000 times the normal rate.
Warm up questions
- What is an endangered species? Can you think of five animals that are categorized as endangered?
- What might lead to the extinction of a plant or animal?
- Do you think it truly matters if a species goes extinct?
Critical thinking questions
- How do you think scientists know that there has been a dramatic decrease in the number of monarch butterflies? What tools or strategies might they use to gather this information?
- Why are scientists concerned that the monarch butterfly population has become so low? What implications might it have for other species, including humans?
- Do you think classifying the monarch butterfly as endangered would help to save them? What are the risks and benefits to categorizing them this way? How do you think farmers who use pesticides will react to this idea?
