| Proterozoic Eon 2.5 billion years ago to 540 mya |
Vendian Period 600 to 540 Million Years Ago |
Vendian biota (Ediacara fauna), multi-celled, animals appear, including sponges. A mass extinction occurred. The continents had merged into a single supercontinent called Rodinia. | ||
| - | First multicellular life: colonial algae and soft-bodied invertebrates appear. Oxygen build-up in the Mid-Proterozoic. | |||
| Archeozoic Eon (Archean) 3.9 to 2.5 billion years ago |
- | "Ancient Life" - The first life forms evolve - one celled organisms. Blue-green algae, archaeans, and bacteria< appear in the sea. This begins to free oxygen into the atmosphere. | ||
| Hadean Eon 4.6 to 3.9 billion years ago |
- | "Rockless Eon" - The solidifying of the Earth's continental and oceanic crusts. | ||
Enchanted Learning®
Over 35,000 Web Pages
Sample Pages for Prospective Subscribers, or click below
|
Overview of Site What's New Enchanted Learning Home Monthly Activity Calendar Books to Print Site Index K-3 Crafts K-3 Themes Little Explorers Picture dictionary PreK/K Activities Rebus Rhymes Stories Writing Cloze Activities Essay Topics Newspaper Writing Activities Parts of Speech Fiction The Test of Time
|
Biology Animal Printouts Biology Label Printouts Biomes Birds Butterflies Dinosaurs Food Chain Human Anatomy Mammals Plants Rainforests Sharks Whales Physical Sciences: K-12 Astronomy The Earth Geology Hurricanes Landforms Oceans Tsunami Volcano |
Languages Dutch French German Italian Japanese (Romaji) Portuguese Spanish Swedish Geography/History Explorers Flags Geography Inventors US History Other Topics Art and Artists Calendars College Finder Crafts Graphic Organizers Label Me! Printouts Math Music Word Wheels |
Click to read our Privacy Policy
| Search the Enchanted Learning website for: |