Geologic History

Which statement best describes the principle of uniformitarianism? (Mark the one best answer.)

• Deposition occurs faster today than it did in ancient environments.

• Rocks form by the same processes today as in the past

• Weathering and erosion can be fast or slow, depending on the type of rock.

• Earth’s geological features were formed by a few catastrophic events.

Why is uniformitarianism an important principle to consider when making inferences about how Earth’s geology has changed over millions of years? (be sure to restate and answer the question!)

• Uniformitarianism is about organisms wearing a uniform

• Uniformitarianism is about everything on the planet being exactly the same.

• Uniformitarianism is when someone clones all organisms to make them identical to all other organisms on the planet.

• Uniformitarianism says that the processes that shape Earth are the same throughout time. That means if we observe a process shaping Earth today, we can assume the same process shaped Earth in the past and will shape Earth in the future all over the planet and even on other planets.

Do scientists think that new rocks are still forming today? How does uniformitarianism help scientists answer the first question?

• Today we see evidence of rock formation like cementation in mudstone, sediments layering, and volcanoes erupting, but most rock formation is impossible for us to observe (see how rocks actually form) directly. However, if rocks were not still forming today, the Earth's surface would probably be smooth and level due to constant weathering, with thick layers of sediments. We know that is not the case. Uniformitarianism helps explain this because it suggests that the processes that we see today are the same as in the past and will be in the future.

• We cannot see rock formations and there for we have no idea how rocks actually form.

• Weathering does not affect rock size at all and there for there is no need for any new rocks to ever form. Whatever is on the planet millions of years ago is still here and has not changed over time.

• Uniformitarianism does not explain how new rocks form because it is about how things are all the same.

Which era are we in now?

• Precambrian
• Mesozoic
• Paleozoic
• Cenozoic

Which eon is the Mesozoic in?

• Phanerozoic
• Precambrian
• Cenozoic
• Cambrian

Which era is the Cambrian period in?

• Cenozoic
• Mesozoic
• Paleozoic
• Hadean

Which period are we currently in?

• Quaternary
• Holocene
• Jurassic
• Tertiary

If a fossil was found in the triassic time period and another in the cambrian time period, which one is older?

• Triassic

• Cambrian

• Jurassic

• Tertiary

Scientists who study fossils are called

• Geologists
• Paleontologists
• Fossil Scientists
• Meteorologists

What type of fossil is this?

• Mold
• Cast
• Preserved remains
• Trace fossil