Which scenario exemplifies global extinction?

The scenario of complete loss of a species, such as dinosaurs or the Javan tiger, exemplifies global extinction because it signifies that the species has entirely vanished from the Earth and can no longer be found anywhere in any habitat. When a species goes extinct, it means that all individuals of that species have died out, eliminating their presence from biodiversity entirely.

This concept of global extinction underlines the importance of species conservation, as once a species is extinct, it cannot be brought back, and the ecological roles it played are lost permanently. For instance, dinosaurs represent a significant extinction event that has had profound implications for the evolution and development of life on Earth. The Javan tiger, similarly, serves as an example of how human activities can lead to the complete disappearance of a species, emphasizing the stakes involved in biodiversity preservation.

In contrast, options discussing human disruption of an ecosystem or a temporary decline in population size do not constitute global extinction since they suggest the possibility of recovery or persistence of species in other areas. Additionally, the loss of a species from one area while remaining elsewhere indicates that the species is not globally extinct, as it continues to exist in certain locations.