Fossil Record

Question

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.

Constructed Response Question
The image shows a fossil.

Identify the era in which the fossilized organism most likely emerged. Provide an explanation.

Answer 1

Without seeing the specific fossil image, I can provide a general approach to answering the question based on the characteristics of organisms found in the three geological eras: Paleozoic, Mesozoic, and Cenozoic.

If the fossilized organism is an invertebrate or a jawless fish, it most likely emerged during the Paleozoic era. This era is known for the emergence of the earliest life forms, including simple invertebrates.

If the fossil belongs to a dinosaur, it would have emerged in the Mesozoic era. This era is often referred to as the "Age of Dinosaurs," during which these reptiles thrived.

If the fossil represents an early mammal or a modern mammal, it would likely be from the Cenozoic era. This period marks the rise of mammals and includes the development of various familiar modern species.

To provide a complete answer, identify the specific characteristics of the fossil, such as its anatomy and features, and correlate these with the organisms known from each era. Based on this analysis, you can conclude which era the fossilized organism most likely emerged from and explain your reasoning accordingly.