This is a Keynote (Mac's version of PowerPoint) presentation that is the 3rd in a 3-part unit on Ecology. * NOTE: I do have a PowerPoint version also available on this teacherspayteachers.com site. This presentation contain 47 slides. This unit covers human impact on ecosystems. It discusses human population growth, the population and consumption crisis, and specific pressures on ecosystems and resources. Biodiversity and extinctions are discussed, including terms, causes, issues and human efforts to preserve species and ecosystems, including legislations. Greenhouse effect and Global Warming are also covered.