Fossils

Fossils can be the actual remains of an animal turned into rock or can simply be impressions left behind, like stamps. Fossils usually occur in sedimentary rock. This type of rock is formed when sand or mud settles at the bottom of seas, rivers, lakes, or marshes.

Sediment or layers of dirt build upon each other, putting pressure on the lower layers until after thousands of years, rock is formed.

Trilobites are animals that played an important role in our planet’s history. We discovered them when we found their fossils.

Fossils form when animals die in specific conditions that allow their remains to be fossilized before they decompose or are eaten. For example, a dinosaur could have died on the shore of a lake. 

Over time, it could have rotted and its bones washed into the lake, where they were covered with sand, and layer upon layer of sediment covered that sand. Time passed until the sand and sediment turned into sedimentary rock.

Eventually, the bones also turned to rock as the organic material was replaced by minerals.

Mud and sediment build up, covering the dinosaur. The lake dries up and the dinosaur remains buried.

There are two main types of fossils: fossilized body parts and fossilized traces. Fossilized body parts are preserved remains of animals such as bones, teeth, shells, or even eggs. Although sometimes softer parts of the bodies are fossilized, this is rare.

Usually, softer parts decompose or rot more easily, meaning they aren’t preserved. Sometimes, minerals replace the actual body parts. Fossilized traces refer to signs of presence left by animals such as footprints, skin prints, nests, tooth marks, or even feces. 

Skin impressions are examples of fossilized traces. Due to the composition of the soft tissue, skin itself cannot be fossilized.

Paleontologists use many tools to clean and examine the fossils. Here, a brush is being used to clean dirt off a bone segment.

Paleontologists must work at uncovering a fossil very carefully because of how fragile some of the pieces are.

Sometimes, retaining walls must be built to make sure the dig area is safe and that the excavated area doesn’t collapse.

Paleontologists can learn a lot from fossils. They can try to get an idea of what life was like millions of years ago. Through the study of ancient creatures, scientists can learn about past climate changes to predict similar events in the future.

Merychippus lived approximately 20 million years ago.

Paleontologists also discover and help preserve biological history, which gives us more of an understanding of our world. The details of how evolution occurred and the clues to the origins of life itself on our planet are found in fossils.