Researchers were digging in the desert when they came across a fossilized cactus leaf buried in the sand.

Environments can change over time. Some places stay the same. What might this environment have been in the past?

Gordon Hubbell and a crew of fossil hunters were digging holes in the desert of Peru in 1988. This desert is one of the driest places on Earth. It gets almost no rain. Hubbel was digging and found jawbones and more than 200 sharp teeth. He is an expert in fossilized sharks, so he recognized the teeth right away. They were shaped like triangles and came to a very sharp point. They belonged to a distant relative of the great white shark!

Why is Hubbell's discovery surprising?

In the Arctic, there are large sheets of ice. Scientists have found palm branches fossilized in the ice.

This tells researchers that the environment may have changed. What might this environment have been in the past?

Antarctica is the coldest place on our planet. Temperatures can reach -120oF, and winds can be powerful. There are no plants or animals that can make their homes permanently in central Antarctica. Scientists were exploring a place called the Dry Valleys and found fossils of moss and small animals. They were discovered in ancient lakebeds. When researchers found the age of the fossils, they were about 14.1 million years old. Scientists realized that shrubs grew around the lakes, and insects lived there too. For insects and plants to survive this area, it had to be warmer and more welcoming to life than it is today.

What did scientists discover that led them to believe Antarctica was once a very different place?

Antarctica is the coldest place on our planet. Temperatures can reach -120oF, and winds can be powerful. There are no plants or animals that can make their homes permanently in central Antarctica. Scientists were exploring a place called the Dry Valleys and found fossils of moss and small animals. They were discovered in ancient lakebeds. When researchers found the age of the fossils, they were about 14.1 million years old. Scientists realized that shrubs grew around the lakes, and insects lived there too. For insects and plants to survive this area, it had to be warmer and more welcoming to life than it is today.

Which two sentences are evidence that there was a change in the environment over time?

High up in the Himalaya Mountains, fossils of fish and other aquatic sea animals have been found. These mountains are hundreds of miles away from the closest sea. They are snow-capped at the tip, and the land is dry and brown. The layered rocks of the Himalayas are rich with not only fossils of aquatic creatures but also fossils of coral reef remnants and marine plants.

What does this information tell researchers or scientists?

Gordon Hubbell and a crew of fossil hunters were digging holes in the desert of Peru in 1988. This desert is one of the driest places on Earth. It gets almost no rain. Hubbel was digging and found jawbones and more than 200 sharp teeth. He is an expert in fossilized sharks, so he recognized the teeth right away. They were shaped like triangles and came to a very sharp point. They belonged to a distant relative of the great white shark!

What did these fossils tell scientists about the environment in which they were found?

High up in the Himalaya Mountains, fossils of fish and other aquatic sea animals have been found. These mountains are hundreds of miles away from the closest sea. They are snow-capped at the tip, and the land is dry and brown. The layered rocks of the Himalayas are rich with not only fossils of aquatic creatures but also fossils of coral reef remnants and marine plants.

Where would these types of fossils typically be found?

What do fossils show about environments of long ago?

Researchers were digging in the desert when they came across a fossilized cactus leaf buried in the sand. This discovery proves that this environment has changed immensely over time.