Biostratigraphy relies on the principle that fossils evolve over time, and the presence or absence of specific fossils in a rock layer can be used to determine the relative age of that layer compared to other layers.

Index fossils are fossils of organisms that are widely distributed, easily recognizable, and have a short geologic range, making them useful for precise dating and correlation of rock layers.

Relative dating in biostratigraphy establishes the order of events based on the sequence of fossil assemblages, while absolute dating provides specific numerical ages using radiometric or other methods.

The Mesozoic Era, also known as the Age of Dinosaurs, lasted from approximately 252 to 66 million years ago and is characterized by the dominance of dinosaurs as the dominant terrestrial vertebrates.

Mass extinction refers to a significant reduction in biodiversity, where a large number of species become extinct within a relatively short geologic time interval.

Foraminifera, single-celled organisms with calcareous tests, are abundant and diverse in marine environments and are widely used for biostratigraphic correlation due to their rapid evolution and wide geographic distribution.

Speciation refers to the process by which new species arise from existing species through genetic divergence and reproductive isolation.

Trace fossils, such as footprints, burrows, and trails, provide insights into the behavior and lifestyle of ancient organisms, including their locomotion, feeding habits, and social interactions.

Faunal succession refers to the gradual change in the composition of a fossil assemblage over time, reflecting changes in the environment, climate, and ecological interactions.

The Cenozoic Era, also known as the Age of Mammals, began approximately 66 million years ago and is characterized by the emergence and diversification of flowering plants, as well as the rise of mammals as the dominant terrestrial vertebrates.

Adaptation refers to the process by which organisms evolve traits that enhance their survival and reproductive success in a particular environment.

Pollen and spores, produced by plants, are abundant and well-preserved in continental environments and are widely used for biostratigraphic correlation due to their rapid evolution and wide geographic distribution.

Evolution refers to the process by which a species gradually changes over time, resulting in the accumulation of genetic and phenotypic changes.

The Paleozoic Era, also known as the Age of Invertebrates, lasted from approximately 541 to 252 million years ago and is characterized by the dominance of trilobites, as well as the diversification of other invertebrate groups.

Extinction refers to the process by which a species ceases to exist, resulting in the loss of its entire population.