Study Guide: A Brief History of Life
- Put the geological time periods from smallest to largest: eras, eons, periods. 
- List the eons in order from oldest to youngest. 
- What three eras are in the Precambrian Eon, in order? 
- As far as we know, how old is the Earth? 
- As far as we know, when did life begin on Earth? 
- How do we date rocks? 
- What was the atmosphere like in the Precambrian Eon? 
- What was life like in the Precambrian Eon? 
- What the main determinant of the Precambrian Eon? What defines the boundary between the Precambrian and the Phanerozoic? 
- What event started the Hadean Eon? 
- What events happened during the Hadean Eon? 
- What marks the transition from the Hadean Eon to the Archaean Eon? 
- What marks the transition from the Archaean Eon to the Proterozoic Eon? 
- What is the first chemical evidence we have of life on Earth? 
- What is the first physical evidence we have of life on Earth? 
- Why was the oxygenation of ocean and the atmosphere so important for life on Earth? 
- How is it theorized that aerobic respiration came to be in eukaryotic organisms? 
- What marks the transition from the Precambrian Eon to the Phanerozoic Eon? 
- What eon did the moon form? 
- What eon did liquid water form on Earth? 
- What eon did the Earth formation complete? 
- What eon did the first oceans appear? 
- What eon did the Earth experience heavy bombardment from large asteroids? 
- What eon did the origin of life appear? 
- What eon did photosynthetic cells appear? 
- What eon did the first evidence of oxygenic photosynthesis appear? 
- What eon did first cyanobacteria appear? 
- What eon did the first eukaryotic organisms appear? 
- What eon did the lichen-like organism appear? 
- What eon do we have the first evidence of sexual structures? What type of organism? 
- What eon did the oceans become completely oxygenated? 
- What eon did the first animals appear? What were they? 
- What major life forms first appeared during the Cambrian Explosion? 
- Why is the Cambrian Explosion so important? 
- Why did Darwin struggle to explain the events of the Cambrian Explosion with his theory of natural selection? 
- What is the theory of punctuated equilibrium? (and who came up with it)? 
- What are three possible causes of the Cambrian Explosion? 
- Know the fossil evidence for the Cambrian Explosion. What type of fossils existed in the following sites and what are their relative temporal relationships: Doushantuo, Ediacara Hills, and the Burgess Shale. 
- What is the largest extinction event (other than current times) in the history of Earth? 
- What percentage of marine species went extinct in the Permian-Triassic extinction? Terrestrial species? 
- What are the possible causes of the Permian-Triassic extinction? 
- Why did the Permian-Triassic extinction cause a greater decline in marine species, compared with terrestrial species? 
- What happened in the Mesozoic Era? 
- What happened during the Cretaceous-Paleogene extinction? What is the culprit? What evidence supports this? 
- From an animal perspective, the Cenozoic Era is known as the Age of the ____. 
- What type of plants came to dominate during the Cenozoic? 
- Insect pollination is a mutualistic relationship that blossomed during which era? (You get it…blossomed!!!) 
