Biology

Chapter 12 Sustaining Biodiversity: The Species Approach Core Case Study: The Passenger Pigeon - Gone Forever Once the most numerous bird on earth. In 1858, Passenger Pigeon hunting became a big business. By 1900 they became extinct from over-harvest and habitat loss. Figure 11-1 SPECIES EXTINCTION Species can become extinct: Locally: A species is no longer found in an area it once inhabited but is still found elsewhere in the world. Ecologically: Occurs when so few members of a species are left they no longer play its ecological role. Globally (biologically): Species is no longer found on the earth. Global Extinction Some animals have become prematurely extinct because of human activities. Figure 11-2 Endangered and Threatened Species: Ecological Smoke Alarms