Petroleum is a fossil fuel that was formed from the remains of ancient organisms. Millions of years ago, many organisms lived in shallow seas. These organisms eventually died and sank to the seafloor where they became buried in layers of sediment. After millions of years under high pressure and high temperature, the remains of these organisms transformed into fossil fuels, including petroleum. Today, petroleum is found underground and then removed with giant drilling machines. The pictures show how petroleum was formed.

Question

The left picture shows an ocean 300 to 400 million years ago. The ocean has fish, starfish, plants, corals, and rocks. The middle picture shows an ocean 50 to 100 million years ago. The ocean has fish, plants, corals, rocks, a layer of sand and silt, and a layer of plant and animal remains. The right picture shows a present-day ocean. An oil drill sits on a layer of sediment and rock, which sits on top of oil deposits. The oil drill is shown drilling into the oil deposits.

The picture shows where petroleum can be found on Earth.

The map shows that the regions of major petroleum deposits are mostly along the coasts of North America, South America, Europe, Africa, Asia, and Australia. Some petroleum deposits are found more inland in North America, Europe, and Asia.

Constructed Response Question
Two students are having a discussion about petroleum. Student A claims that petroleum is formed quickly, and that the world will never run out of it. Student B claims that petroleum is formed slowly, and that the world could run out of it.

Which claim is correct? Provide an explanation.

Answer 1

Student B's claim is correct. Petroleum is formed slowly over millions of years from the remains of ancient organisms that live in shallow seas. This process requires specific conditions, including high pressure and high temperature, which take considerable time to develop. The transformation of organic material into fossil fuels like petroleum occurs over geological time scales, not rapidly.

Due to this slow formation process, the rate of petroleum consumption today far exceeds the rate at which new petroleum is created. This means that though there are significant known reserves of petroleum, these reserves are finite. Once they are depleted and new sources cannot be formed quickly enough to keep pace with demand, we could experience shortages. Therefore, it is possible that the world could eventually run out of petroleum, particularly if alternative energy sources are not developed and adopted to replace it.