 What is a fossil? A fossil is the preserved remains or imprint in a rock of a plant or animal, usually one that lived a long time ago. Many of the fossils discovered so far are ancestors of organisms living today, while some fossils are the remains of organisms that still exist. The study of fossils is called paleontology. The total number of fossils and their placement within rocks is known as the fossil record. Much of what we understand about evolution comes from studying fossils, so they are really important, but how do they form? When animals or plants die, they remain usually decayed to nothing. It is only if the conditions are right that they can be preserved as fossils. The best way to create a fossil is to trap and quickly bury a dead organism. The dead remains of animals and plants that fall to the river or seafloors get covered in layers of sediment. Over time, this sediment sinks as it is buried deeper by increasing layers. Meanwhile, minerals permeate through the sediment and gradually recrystallize the non-decomposed remains. This process is called permineralization. In some cases, the whole skeleton eventually dissolves, leaving a space in the sediment which becomes filled with mineral deposits in the exact shape of the original structure. In this way, a cast of the original structure is created. Eventually, the pressure exerted on the lower layers of sediment is sufficient to turn it into rock. Millions of years later, this rock may rise to the Earth's surface, where erosion and earthquakes eventually expose the fossil. While whole-body fossils can be created in this way, and so can trace fossils. Trace fossils are the fossilized remains of things animals or plants have left behind. This includes footprints, tracks, dung, and even lightning strikes. Another way to create a fossil is by covering a specimen with a non-porous coating. Amber is the fossilized remains of sticky tree sap produced millions of years ago. Any insect or plant which was trapped in this tree sap would have become quickly coated and there would have been little opportunity for the remains to decay. Fossilized remains of plants and animals made in a similar way are sometimes found in peat bogs, tar pits, or ice. So in this video, you have learned what fossils and the fossil record are. You have been shown different ways in which fossils are created and have seen the difference between body and trace fossils. Do you have any fossils or are there any fossils in the area where you live? If you liked the video give it a thumbs up and don't forget to subscribe. Comment below if you have any questions. Why not check out our Fuse School app as well? Until next time.