Question

Fossil Record



The location of fossils in the layers of Earth, known as the fossil record, can be used to learn about the history of Life on Earth. Scientists study patterns in the fossil record to help them understand changes in life forms throughout history. The location of fossils within Earth's layers creates a timeline that scientists can use to determine the existence of life and how organisms evolved.



The diagram shows three important eras of the fossil record and the types of fossils they contain.



Three eras—Paleozoic, Mesozoic, and Cenozoic—are shown from the bottom to the top of the diagram. Each era is divided into fossil layers. In the Paleozoic era at the bottom of the diagram, the fossil record shows invertebrates in the lowest fossil layer, then, as the layers move up, jawless fish, jawed fish, amphibians, and reptiles. In the Mesozoic era in the middle of the diagram, the fossil record shows only dinosaurs. In the Cenozoic era at the top of the diagram, the fossil record shows early mammals in the lower layers and modern mammals in the upper layer.






Which provides the BEST evidence of a mass extinction?


An absence of fossils in layers of the fossil record.


The evolution of a single species in the fossil record.


Organisms becoming more complex in the fossil record.


The emergence of a new species in the fossil record.

Answer 1

An absence of fossils in layers of the fossil record.

Explanation: A mass extinction causes a sudden, widespread loss of many species, producing a gap or abrupt drop in fossil types between layers. The other options describe gradual changes or single-species events, not widespread, sudden losses.