Encountering Geologic Time Educational ApplicationsEducational Applications Educational Application of Computers Fall II 2009 – 2010 EDUU 551 Charles Pardue

What is meant by Geologic Time? Geologic time is the interval of time occupied by the Earth's geologic history, extending from 3.9 billion years ago (corresponding to the age of the oldest known rocks) to the present day It is the part of the Earth's history that is recorded in rock strata The geologic time scale is classified in nested intervals distinguished by characteristic geologic and biologic features From longest to shortest duration, the intervals are: eon, era, period, and epoch

Geologic Time Terms Geologic time is grouped into the following divisions:  Eon – The longest division of geologic time (1,000,000,000 years or more)  Era – A major division of geological time consisting of two or more periods ( million years)  Period - A division of geological time (usually describing a system of rocks)  Epoch - Subdivisions of a period and are themselves subdivided into ages (tens of millions of years)  Age – Smallest division of geologic time (millions of years)

Important Dates in Earth’s History (In millions of years) 4600 Origin of the Earth 3900 Oldest Dated Crustal Rocks 3800 Oldest Evidence for Life 2000 First Oxygen Atmosphere/Ozone Layer Forms 900 Oldest Metazoan Fossils 510 Oldest Fossil Fish 458 First Land Plants 375 Important first step: Amphibians Evolve 245 Huge Mass Extinction (end of Permian Period & Paleozoic Era)

Important Dates in Earth’s History (In millions of years) 200 First Mammals 160 First Birds 145 Atlantic Ocean first opens 130 Angiosperms (Flowering Plants) appear 65 Adaptive Radiation of Mammals/Dinosaurs Go Extinct (Close of the Mesozoic/Beginning of the Cenozoic Era) 3.4 Age of (LUCY) Australopithecus afarensis fossils 2 Pleistocene Ice Age begins.600 Age of Homo erectus fossils from Ethiopia.100 Homo sapiens appears in the fossil record.015 Last ice sheet retreats ?? Your Birthday

Climbing the Geologic Time Scale Let’s climb Mt. Everest to explore the geologic Time Scale Mt. Everest is 29,029ft or 8,848m in height Every 1,000m would approximate 520 million years Every 1,000ft would approximate 160 million years One meter would approximate 520,000 years One foot would approximate 159,000 years

The First Mile (Hadeon Eon) Our climb starts in the Hadeon Eon, (also known as the Rockless Eon) 4.6 to 3.9 billion years ago (0 – 4413ft/1347m/.84mi) At this time, there is no life on earth The crust of the Earth is solidifying into continental and oceanic plates This Eon lasted 700 million years

The Second Mile (Archeozoic Eon) Our second mile finds us in the Archeozoic Eon, 3.9 to 2.5 billion years ago (4413ft/1347m/.84mi – 8826ft/2693m/1.67mi) "Ancient Life" - The first life forms evolve - one celled organisms Blue-green algae, archaeans, and bacteria appear in the sea Free oxygen begins to appear into the atmosphere This eon lasted for 1.4 billion years

Miles Three & Four (Proterozoic Eon) 13,239ft/4,040m/2.51mi (Almost halfway up!) finds us at the beginning of the Proterozoic Eon The first multicellular life begins to appear: Colonial algae and soft-bodied invertebrates Oxygen builds up measurably in the Mid-Proterozoic Sponges appear in the Vendian/Ediacaran Period (600 to 540 million years ago) The first major extinction event occurs and all land on Earth is part of the super-continent, Rodinia This eon lasted for 1.96 billion years

Mile Five & Beyond (The Phanerozoic Eon) This eon begins at 25,596ft/7,811m (4.85 miles) This eon contains the Paleozoic, Mesozoic & Cenozoic eras The majority of all life known to us today arose during this eon We have 3404ft/1039m/.64mi left in our climb This eon began 540 million years ago

The Paleozoic Era (Life explodes) The Phanerozoic eon begins with the Paleozoic era and the Cambrian period (Age of Trilobites) An explosion of life occurs and all existing phyla that we know today develop: Vertebrates, mollusks, primitive fish Toward the end of the Cambrian period, the supercontinent Rodinia breaks into smaller land masses and a mass extinction event occurs taking half of all life on earth, probably through glaciation The Cambrian period lasts 40 million years (252ft/77m) It ends with us at 25,848ft/7,888m/4.9 miles with 3152ft/962m remaining

Plants, Fishes & Insects During the Ordovician period the first plants & fungi appear on land along with corals, seaweeds and gastropods in the sea This period ends with another major extinction and finds North America under shallow seas We are now at 26,239ft/8,007m/4.97mi and have 2,761ft/843m/.52mi left to climb The Silurian period also gives rise to insects, jawed fishes, crinoids and vascular plants and at its end we have 2,572ft/785m/.49mi left to climb The first amphibians occur during the Devonian period (Age of fishes) along with sharks, bony fish and coral reefs along with another extinction that takes about 30% of all life on earth

Amphibians, Reptiles, Flight & Coal At 26,730ft/8,157m/5.06mi with 2,270ft/693m/.43mi remaining, we find ourselves at the beginning of the Carboniferous period Here we find the first flying animals (winged insects) along with the first reptiles and ferns There are also large swamps which will form the basis of the world’s coal Amphibians and reptiles dominant the Permian period and oxygen rises close to modern levels Another mass extinction event occurs at the end of the Permian period/Paleozoic era which takes 50% of all animal families and 95% of all marine species

Dinosaurs & Mammals At 27,437ft/8,373m/5.2mi, we are 1,526ft/477m/.3mi from the top and encounter the Mesozoic era (the age of reptiles) This era contains the Triassic, Jurassic and Cretaceous periods Dinosaurs, crocodiles, turtles and mammals emerge during the Triassic which ends with another minor extinction (35% of all animal families die out) and clear the way for the expansion of the dinosaurs During the Jurassic period, the first birds and flowering plants appear along with the giant Sauropods and flying Pterosaurs The Cretaceous period is the heyday of the Dinosaurs, along with butterflies, bees, snakes, ants and marsupials appearing

Mammals, Mammals, Mammals At 28,590ft/8,725m/5.41mi, the Mesozoic era and the Cretaceous period end with the K-T extinction event which ends the reign of the dinosaurs and also takes about 50% of all marine invertebrate species We are 410ft/125m from the top of Mt. Everest and entering the Cenozoic era (the age of mammals) This begins with the Tertiary period where the first large mammals appear along with primitive primates Rodents and primitive whales make their appearance along with grasses, deer, cats, modern birds and the first apes and hominids toward the end of the Tertiary period This period ends with us at 11ft/3m from the top of Mt. Everest

The Quaternary Period (Age of Man) We begin this period 11ft/3m and 1.8 million years from the top of Mt. Everest The first humans begin to evolve along with mammoths, mastodons, saber-toothed cats and giant ground sloths Another mass extinction occurs around 10,000 years ago that removes many large mammals and birds, probably caused by the change of environment at the end of the last ice age This ends the Pleistocene epoch and we are.07ft/.02m from the top of Mt. Everest

Human Civilization We are now almost at the summit of Mt. Everest with.07ft/.02m remaining in our climb In the distance remaining (13/16ths of an inch) all human progress occurs in what is known as the Holocene epoch

Review of our climb A quick review of our climb up Mt. Everest For the first mile of our climb, we encountered no life, with the exceptions of some blue-green algae toward the end Going into the second mile, we found the first primitive unicellular life and signs of free oxygen At around 2.5 miles we found the first signs of multicellular life, more signs of free oxygen and the Cambrian explosion of life which occurred at around 4.5 miles Around a half mile from the top of Mt. Everest, plants, fishes and insects were found, with dinosaurs and mammals about a quarter of a mile later

Review of our climb (cont) In the last quarter mile of our climb, the age of dinosaurs begins and ends with the age of mammals around 400ft from the summit The age of mammals proceeds and ends about 11ft from the top of Mt. Everest The first ancestors of homo sapiens begin to appear at this time and the rise of civilization begins in less than an inch from the summit All progress as we know it takes place in this last 13/16ths of an inch of our 29,000ft climb