What was the Cambrian explosion?

A rapid burst of animal diversity about 540 million years ago

If Earth's history were one day, when would humans appear?

In the last few seconds before midnight

What is the Anthropocene?

A proposed era of human impact on Earth

Geological Time Quiz: Places, People and Key Facts

This geological time quiz covers Earth's age, the geological time scale with eons, eras and periods, the Cambrian explosion, the age of dinosaurs, mass extinctions and the Anthropocene debate. Ten questions on places, people and key facts about deep time.

Start Geological Time Quiz

🎯 Daily Trivia Challenge • 🧠 10 Questions • ⏱️ 150 Seconds

Question 1 / 10 Time: 150s

Age
About how old is Earth?
Scale
What are the largest divisions of geologic time?
Explosion
What was the Cambrian explosion?
Dinosaurs
In which era did dinosaurs live?
Extinction
Which was the largest mass extinction, about 252 million years ago?
Mammals
Which era is called the Age of Mammals?
Hutton
Who is called the father of modern geology for his ideas on deep time?
Map
Who made the first geological map of a country, Britain, in 1815?
Clock
If Earth's history were one day, when would humans appear?
Anthropocene
What is the Anthropocene?

Explanations: answer key for all 10 questions

Q1: About how old is Earth?
Answer: About 4.54 billion years
Radiometric dating of meteorites shows this.
Q2: What are the largest divisions of geologic time?
Answer: Eons
Eons are split into eras, periods and epochs.
Q3: What was the Cambrian explosion?
Answer: A rapid burst of animal diversity about 540 million years ago
Many animal groups appeared.
Q4: In which era did dinosaurs live?
Answer: Mesozoic
It includes the Triassic, Jurassic and Cretaceous.
Q5: Which was the largest mass extinction, about 252 million years ago?
Answer: End-Permian
About 90% of marine species died.
Q6: Which era is called the Age of Mammals?
Answer: Cenozoic
It began 66 million years ago.
Q7: Who is called the father of modern geology for his ideas on deep time?
Answer: James Hutton
He wrote in the 1780s.
Q8: Who made the first geological map of a country, Britain, in 1815?
Answer: William Smith
He used fossils to match layers.
Q9: If Earth's history were one day, when would humans appear?
Answer: In the last few seconds before midnight
Humans are very recent.
Q10: What is the Anthropocene?
Answer: A proposed era of human impact on Earth
In 2024 geologists voted against making it official.

Geological Time Quiz – Deep Time

Earth is about 4.54 billion years old, a span so vast it is called deep time. Geologists divide it into eons, eras, periods and epochs based on changes in rocks and fossils.

Major events mark the timeline: the first life over 3.5 billion years ago, oxygen filling the atmosphere, the Cambrian explosion of animals, the rise and fall of dinosaurs and the age of mammals. Five great mass extinctions reshaped life.

Thinkers like James Hutton and Charles Lyell argued that slow processes shaped Earth over immense time, and radiometric dating later confirmed Earth's age. Humans have existed for only a tiny fraction of this history.

What This Quiz Teaches

This quiz is for students learning geological time.

How old Earth is
What eons and eras are
What the Cambrian explosion was
Which extinction was largest
What the Anthropocene is

Did You Know?

The Precambrian covers most of Earth's history.
The Jurassic was named after the Jura Mountains.
Grand Canyon rocks span nearly 2 billion years.
Zircon crystals can be over 4 billion years old.
Earth's oxygen rose about 2.4 billion years ago.