| A | B |
|---|
| Cambrian | 1. explosion of multicellular forms 2. lots of trilobites 3. 80% of life gone at end of period |
| Ordovician | 1. Lots of Invertebrates--like tilobites, ammonites, and sea scorpions |
| Silurian | Jawless fish and sharks |
| Devonain | Boney fish, and early non-vascular land plants |
| Carboniferous | Giant Insects and amphibians arrive 2. Oil, gas and coal form 3. cycads and tree ferns |
| Permian | Reptiles, ferns, and conifers arrive 2. 95% of plants and animals die. Pangaea forms |
| Triasic | 1. First dinosaurs adn sea reptiles arrive (icthyosaurs and plesiosaurs.) Pangea breaks up at the end of this period |
| Jurassic | Gigantic Dinosaurs, birds and rat-like mammals arrive |
| Cretaceous | Flowering plants begin. 70% of all life dies by end of period. |
| Paleocene | Mammals like rats, squirrels, and wolves arrive |
| Eocene | Mammals invade all biomes and form the groups we see today |
| Oligocene | Many mamal groups become very large--grasses begin |
| Miocene | 1. Similar to Oligocene 2. Primates begin 3. Large mammals become extinct by end of period |
| Pliocene | 1. Hominid ancestor of man 2. Forests are dimished and grasslands increase |
| Pleistocene | Homo Sapiens and Homo Neanderthalus begin 2. Ice Age Advances 3. Mass extinction at the end. |
| Holocene | Modern age. Human civilzation develops--mass extinctions due to human activity |
