Fossils may form in other ways. Fossils can be preserved almost completely. In this process, the organism doesnt change much. As seen below, tree sap may cover an organism. With time, the sap hardens. It turns to into amber. The original organism is preserved. This is very exciting for scientists. They are able to study the DNA of the organism that no longer lives on Earth. Some animals have been found frozen in ice. Others have been found in tar pits after falling in. Molds and casts are another way organisms can be fossilized. Have you ever walked in soft mud and left footprints? Once in a while, these traces of organisms can be preserved. In this case, nothing is left of the organism. A mold is an imprint of an organism that is preserved in rock. The organisms remains break down completely. There is nothing left of the original plant and animal.

When tree sap covers an organism and hardens, what does it become?

Earthquakes seemed to outline a special feature of earth's crust. Earthquakes let scientists know where the crust was moving. This led to the discovery that the Earths crust was broken up into regions, or plates. Earthquakes happen most often along these plate boundaries. This was evidence that continents can move. The movements of the plates are called plate tectonics. The Earths crust is divided into plates. There are about a dozen large plates and several small ones. Each plate is named for the continent or ocean basin it contains. Scientists know he plates are in motion. They now know the direction and speed of this motion . Plates dont move very fast. They move only a few centimeters a year. This is about the same rate fingernails grow. So you might wonder, what could cause this motion? What supplies the energy to cause this change?

To get a sense of how fast plates move, what can you look at on your body?

Befitting a lush, tropical island stranded in the middle of the ocean, Madeira's origins are shrouded in mystery and fanciful legend. Some claim that the archipelago is what remains of Plato's lost Atlantis, or part of a landmass that once fused the continents of Europe and America. The Portuguese Step Ashore: Recorded history of the volcanic archipelago begins in relatively recent times: 1418, just as the golden age of Portuguese discovery was erupting. Under the leadership of Henry the Navigator, caravels set out from the westernmost point of the Algarve, in southern Portugal, in search of foreign lands, fame, and wealth. Joao Goncalves Zarco, sailing in the service of Prince Henry, made the first of many famous Portuguese discoveries, which would culminate a century later in Magellan's historic circumnavigation of the globe. Zarco happened upon a small volcanic archipelago 1,000 km from Lisbon. Perhaps Zarco knew precisely where he was heading, having learned of the existence of Madeira from a Castilian source. After all, the waters of the Canary Islands, only 445 km (275 miles) to the south, had occupied busy shipping lanes for very nearly a century, and Genovese maps from the mid-14th century depict both Madeira and Porto Santo. More likely, Zarco was heading for Guinea and storms forced him onto the beach of Porto Santo. If so, then he was extremely fortunate, for he managed to land on the only large, sandy beach for hundreds of miles around. Little wonder he subsequently named it Porto Santo (Holy Port). The following year Zarco returned to claim the larger island he had seen from Porto Santo, and with him went Tristao Vaz Teixeira and Bartolomeu Perestrelo. They officially became the first men to set foot on the heavily forested island, naming it Ilha da Madeira, "Island of Timber. " The Portuguese Crown, delighted with its first important discovery, immediately embarked on a program of colonization. Zarco and Teixeira were appointed co-governors of Madeira, while Perestrelo was awarded Porto Santo.
Why might a Castillian source have known about the existence of Madeira around the time Zarco was exploring?