Geological Time Scale PDF

GEOLOGICAL TIME SCALE DO YOU KNOW? Geologic time scale divides up the history of the earth based on life- forms that have existed during specific times since the creation of planet. HADEAN EON oldest eon and lasted from 4.6 to 4 billion years it represents the earliest history of earth and ex...

GEOLOGICAL TIME SCALE DO YOU KNOW? Geologic time scale divides up the history of the earth based on life- forms that have existed during specific times since the creation of planet. HADEAN EON oldest eon and lasted from 4.6 to 4 billion years it represents the earliest history of earth and existence of many rocks and life forms just like the molten surface, volcanism, and asteroid impacts. ARCHEAN EON 3.5 billion years ago, Archean eon became the "first life" on the earth the first form of life was created in the ocean by the end of the Archean eon, the ocean floor was covered in a living mat of bacterial life. PROTEROZOIC EON called as "age of hidden life", started 2.5 billion years ago in this time, enough shield rock had formed to start recognizable geologic process such as plate tectonics contain definite life forms such as fossil remain of bacterial life, blue green algae and first oxygen. dependent animal. PHANEROZOIC EON about 541 million years ago, this time in which abundant animal and plant life has existed in early Archean eon, life is clearly originated not until the Phanerozoic did a rapid expansion and evolutions of various ecological niches Phanerozoic eon is subdivided into different era, these are the following; PALEOZOIC ERA 542 to 251 million years ago began from the breakup of one supercontinent and the formation of another. plant became widespread in this era it is divided into different periods; Cambrian period, Ordovician period, Silunian period, Devonian period, Carboniferous period, & Permian period.  CAMBRIAN PERIOD 53 million years ago known for ushering in an explosion of life on earth, included the evolution of arthropods and chordates.  ORDOVICIAN PERIOD 45 million years ago it is marked in the fossil record by an abundance of marine invertebrates. the most famous of these invertebrates was the trilobite  SILURIAN PERIOD 443 to 416 million years ago the spread of jawless fish throughout the seas mollusks and corals thrived in the ocean and land, the first evidence of terrestrial life  DEVONIAN PERIOD 419.2 to 358.9 million years ago called as "age of fishes" because of diverse, abundant and bizarre type of these creatures that swam Devonian sea shell-bearing marine known as ammonites first appeared early in devonian, the first four-legged amphibians appeared indicating the colozination of land by vertebrates.  CARBONIFEROUS PERIOD 359 to 299 million years ago before birds evolved, tetrapods began laying on the land allowing them to break away form an amphibians lifestyle. two new groups evolved; marine reptiles including lizard and snakes archosaurs which give rise to crocodiles, dinosaurs, & birds.  PERMIAN PERIOD 299 to 251 million years ago largest mass extinctions coral reef flourished providing shelter for fish and shelled creatures such as nautiloid and ammoniods. conifers and ginkgo evolved on land terrestrial vertebrates evolved to become herbivores taking advantage of the new plant life that colonized the land.  MESOZOIC ERA about 252 to 66 million years ago known as the "age of reptiles or age of dinosaurs" because of its famous inhabitants. this is divided into different periods; Triassic, Jurassic, and Cretaceous period TRIASSIC PERIOD 252 to 200 million years ago the rise of reptiles and first dinosaurs. JURASSIC PERIOD 200 to 145 million years ago marked the presence of dinosaurs and first appearance of birds. CRETACEOUS PERIOD 145 to 66 million years ago known for its iconic dinosaurs such as triceratops and pterosaurs such as pteranodon. CENOZOIC ERA 65 million years ago and continues to the present the current location of the continents and their modern-day inhabitants including humans can be traced to this period. known as the "age of mammals" because the extinction of many groups of giant mammals allowing smaller species to thrive and diversify because their predators no longer existed. divided into different periods; Paleogene, Neogene, and Quaternary. PALEOGENE PERIOD 65 to 25 million years ago the beginning of this period was a time for mammal that survived the cretaceous period later in this period, rodents and small horses, such as hyrocotherium and rhinoceroses and elephant appears it consist of Paleocene, Eocene, and Oligocene epochs. PALEOCENE EPOCHS 66 to 56 million years ago first major worldwide division of rocks, it is preceded by the cretaceous period. EOCENE EPOCHS 56 to 33.9 million years ago Eocene come from the Greek word "eos" or dawn which refers to modern fauna during this epoch contains the warmest period marked as the icehouse climate and the rapid expansion of the antarctic ice sheet OLIGOCENE EPOCHS 33.9 to 23 million years ago desert became more common and grassland began to spread it had once separated the Europe and Asia dried up and NEOGENE PERIOD 23 to 2.6 million years ago gives rise to early primates including early human bovids including cattle sheep, goats, antelope and gazelle. it consist Miocene and Pliocene epoch MIOCENE EPOCH 23 to 5.3 million years ago a long lasting epoch in which the Earth's climate rebounded from the cooling of Oligocene there was a marked increase in both global temperature and the total number of mammal species. PLIOCENE EPOCH 5.3 to 2.6 million years ago the cooling and drying of the global environment may have contributed to the enormous spread of grasslands and savanna's during this time QUATERNARY PERIOD 2.6 million to the present cave lions, sabre-toothed cats, cave bears, giant deers, woolly rhinoceroses, and woolly mammoths were prevailing species of this period it consist pleistocene and holocene epoch PLEISTOCENE EPOCH 2.58 to 11, 700 years ago a time in which extensive ice sheets and other glaciers formed repeatedly on the landmasses HOLOCENE EPOCH 11,700 years of the earth history "age of man", both continental and marine cover the largest area of the globe of any epoch in the geologic record, but the Holocene is unique because it is coincident with the late and post-Stone Age history of humankind. THANK YOU SO MUCH