What are trilobites? Plant and Animal Era Period Development Humans develop Holocene (.01) Quaternary Pleistocene (1.8) Pliocene (5.3) Miocene (23.8) "Age of mammals" Oligocene (33.7) Tertiary Eocene (54.8) Cenozoic Extinction of dinosaurs and Paleocene (65) many other species. Cretaceous (144) First flowering plants Jurassic (206) "Age of Reptiles" First birds Triassic (248) Mesozoic Dinosaurs dominant. Extinction of trilobites and many other Permian (290) marine animals Carboniferous: Pennyslvanian (323) Record of First Fossil of Fern "Age of Amphibians" First reptiles Carboniferous: Mississippian (354) Large coal swamps Large Amphibians abundant. First insect fossils Devonian (417) "Age of Fishes" Fishes dominant Paleozoic Silurian (443) First land plants First fishes Ordovician (490) "Age of Invertebrates" Trilobites dominant Cambrian (540) organisms with shells First multicellular organisms Precambrian - comprises about 88% of geologic time (4500) First one-celled organisms Origin of Trilobites are an extinct group of arthropods (jointed-legged animals) known from more than 10,000 fossil species. The group Trilobita existed from early in the Cambrian Period (520 million years ago) until the end of the Permian Period (250 million years ago). The name Trilobita is derived from the three (tri-) lobed structure of the exoskeleton, which has a raised central lobe (or axis) and a pair of side lobes, called Pleurae.
Era Period Plant and Animal Development Cenozoic Quaternary Holocene (.01) Humans develop "Age of mammals" Extinction of dinosaurs and many other species. Pleistocene (1.8) Tertiary Pliocene (5.3) Miocene (23.8) Oligocene (33.7) Eocene (54.8) Paleocene (65) Mesozoic Cretaceous (144) "Age of Reptiles" First flowering plants First birds Dinosaurs dominant. Jurassic (206) Triassic (248) Paleozoic Permian (290) "Age of Amphibians" Extinction of trilobites and many other marine animals Record of First Fossil of Fern First reptiles Large coal swamps Large Amphibians abundant. Carboniferous: Pennyslvanian (323) Carboniferous: Mississippian (354) Devonian (417) "Age of Fishes" First insect fossils Fishes dominant First land plants Silurian (443) Ordovician (490) "Age of Invertebrates" First fishes Trilobites dominant organisms with shells Cambrian (540) Precambrian - comprises about 88% of geologic time (4500) First multicellular organisms First one-celled organisms Origin of What are trilobites? Trilobites are an extinct group of arthropods (jointed-legged animals) known from more than 10,000 fossil species. The group Trilobita existed from early in the Cambrian Period (520 million years ago) until the end of the Permian Period (250 million years ago). The name Trilobita is derived from the three (tri-) lobed structure of the exoskeleton, which has a raised central lobe (or axis) and a pair of side lobes, called Pleurae.
10HW_geological_time_scale.docx