Earth's Eras
Geological Facts
Geological Events
Animal Evolution
Riddles
100

It's the first and longest era in Earth's history.

What is the Precambrian Era?

100

It's one of the two most important factors that allowed humans to be the most dominant animal of our current era. 

What is brain size?
or
What is control of fire?

100

It's a natural phenomenon that happened a couple of times in the Cenozoic Era, in which changes in Earth’s motion around the Sun and around itself caused the temperatures to drop fast.

What is the Ice Age?

100

It's a molecule that contains the genetic code that is unique to every individual.

What is DNA?

100

You can see me in water, but I never get wet. What am I?

Reflection

200

It's the shortest and most recent or Earth's eras.

What is the Cenozoic Era?
200

It's the first type of animal that was able to get out of the water, which helped its survival and resulted in its dominance in the following era.

What is a reptile?

200

It's a relatively short interval of time (approximately 11 million years) when a sudden radiation of complex life occurred, and practically all major animal phyla (groups) started appearing in the fossil record.

What is the Cambrian Explosion?

200

It's a community of animals capable of producing offspring with one another.

What is species?

200

I'm a word that starts with "e" and ends with "e", but only have one letter in it.

Envelope

300

It's the era in which there was a sudden appearance of various new organisms and species, especially marine life and plants.

What is the Paleozoic Era?

300

It's a gas produced by the early bacteria on Earth, which allowed life as we know it to exist on Earth.

What is oxygen gas?
(or just oxygen)

300

They are natural phenomena that happened a few times in Earth's history, in which a great number of species cease to exist. Two of those phenomena were the cause of era changes in the way we classify Earth's geological time.

What are mass extinctions?

300

It's a random change in DNA, or "copying errors", usually caused by toxins, chemical substances and radiation.

What is mutation?

300

I've been drawn by the artists these days, and of old;
Yet I'm seen only when all around me is cold.
For most of the time you just live and ignore me;
Then you gasp for me, stop for me, mutter below me.
You might say, in surprise, I've been taken away,
But it's true I've been with you, at least 'til today.
When I leave you, you leave too!
Who am I?

Breath

400

It's the era in which mammals and birds first appeared.

What is the Mesozoic Era?

400
It's a substance released by volcanoes that poisoned the oceans and atmosphere, causing a mass extinction called The Great Dying, at the end of the Paleozoic Era.

What is carbon dioxide?
(or CO2)

400

It was a mass extinction caused by volcanic activity, which killed more than 95% of the marine species at the time, and more than 70% of the land species.

What is The Great Dying?
(or the Permian-Triassic Extinction)

400

It's a non-random process to which each individual is subjected. It determines the survival of the individual or species, depending on how it deals with it.

What is natural selection?

400

I can be quick and then I'm deadly,
I am a rock, shell and bone medley.
If I was made into a man, I'd make people dream,
I gather in my millions by ocean, sea and stream.

Sand

500

It's the era in which Pangea started to separate.

What is the Mesozoic Era?

500

It's a rare chemical element that was found in Mexico and served as the best evidence for the hypothesis of the asteroid impact that caused the extinction of dinosaurs.

What is iridium?

500

It's the idea that the mass extinction of the dinosaurs was caused by the impact of a large asteroid on the Earth.

What is the Alvarez Hypothesis?

500

It's the process that happens during animal reproduction, which causes each offspring to get a different combination of genes from their parents.

What is recombination?

500

I drift forever with the current
Down these long canals they've made
Tame, yet wild, I run elusive
Multitasking to your aid.
Before I came, the world was darker
Colder, sometimes, rougher, true
But though I might make living easy,
I'm good at killing people too.

Electricity