History of life

What early earth like

• Nice and cool

• Hot and filled with toxic gas

• Breath able air

What is the correct order

• Periods, eons,era

• Era,eons,periods

• Eon, periods, eras

These were the first eukaryotes

What is a stromatolite made up of.

This absorbs ultraviolet radiation

Organisms began living on Earth about 3.8 billion years ago.  Then 1.2 billion years ago, ______ evolved

• multicellular organisms

• single celled organisms

• humans

TRUE OR FALSE: The deeper the rock is in the Earth, the newer it is.

• True
• False

Cyanobacteria changed the early Earth's atmosphere by giving off...

• carbon dioxide

• ammonia

• hydrogen

• oxygen

Which era is the most modern and the one that we are currently living in?

• Cenozoic

• Cretaceous

• Permian

Which of the four key principles of Darwin’s theory of natural selection explains why no two zebras have the exact same pattern of stripes?

• overproduction

• variation

• adaptation