- Pleistocene Extinctions: The Death of an Ecosystem Elin Whitney-Smith, Ph.D. We tend to think extinctions only affect the animals which are gone. We forget that animals, vegetation and climate are linked. We also tend to forget that people act on their perceptions of their environment. If their environment changes slowly, they slowly adjust, and their perception of their environment does not ...www.well.com/user/elin/extinct.htm