Vertebrate Declines and the Sixth Mass Extinction

This activity guides the analysis of a published scientific figure from a study that measured species population declines on a global scale. These declines may be a part of Earth’s next mass extinction.

Mass extinctions are catastrophic events in which many species become extinct over brief periods of time. Scientists believe Earth has experienced five mass extinction events in the past 540 million years. As human activities destroy ecosystems around the world, they may trigger a sixth mass extinction in which 75% of the planet’s species disappear in less than 200 years. The figure shows the global distribution of species declines over the past 115 years (1900–2015). The top panels include all land vertebrates (amphibians, birds, reptiles, and mammals). The bottom panels represent bird species only. The “Educator Materials” document includes a captioned figure, background information, graph interpretation, and discussion questions. The “Student Handout” includes a captioned figure and background information.