Geologic Timeline
Scale
10 cm = 1 billion years
1 cm = 100 million years
.1cm = 1 mm = 10 million years
.1 mm - 1 million years
.01mm = 100,000 years
Geologic Timeline
1.Use a metric ruler to mark 10 cm sections on a strip of paper that is about 50 cm long.
2.Label each 10 cm section in order from top to bottom as follows: 1bya(billion years ago), 2 bya, etc. The Earth’s timeline begins at 4.6 bya.
3.Divide each 10 cm section into 10 equal subsections. Divide the top 1 cm into 10 subsections. Calculate the number of years that are represented by 1 mm on this scale.
4.On yours timeline, label the following events:
1.Earth forms – 4.6 billion years ago
2.Cyanobacteria form – 3 billion years ago
3.Eukaryotes form – 2 billion years ago
4.Paleozoic Era begins – 543 million years ago
5.Life comes on land – 345 million years ago
6.Largest mass extinction ends the Paleozoic Era/ Mesozoic Era begins – 248 million years ago
7.Dinosaurs rule – 206 million years ago
8. Flowering plants appear – 144 million years ago
9. Mesozoic Era ends/ Cenozoic Era begins – 65 million years ago
· 10. Earliest hominids – 7 million years ago
· 11. Homo habilis – 2 million years ago
· 12. Homo erectus – 1 million years ago
13. Neanderthals – 400,000 years ago
14. Homo sapiens – 100,000 years ago
