Earth's History and Diversity of Life
What is Earth's geologic history?
How has the diversity of life on Earth changed over time?
The geologic time scale interpreted from rock strata provides a way to organize major historical events in Earth's history. Analysis of rock strata and the fossil record, which documents the existence, diversity, extinction, and change of many life forms throughout history, provide only relative dates, not an absolute scale. Changes in life forms are shaped by Earth's varying geological conditions.
Scientists estimate the age of the Earth to be approximately
~4.543 Billion Years Old
How do organisms change over time?
Adaptation by natural selection acting over generations is one important process by which species change in response to changes in environmental conditions. The resources of biological communities can be used within sustainable limits, but if the ecosystem becomes unbalanced in ways that prevent the sustainable use of resources, then ecosystems degradation and species extinction can occur.