Geologic Time Scale PDF

GEOLOGIC TIME SCALE GEOLOGIC TIME SCALE A timeline that illustrates Earth’s history based on geologic events and lifeforms. This is a system that chronologically relates geological strata (stratigraphy) to time.  4 MAJOR DIVISIONS OF THE GEOLOGIC TIME SCALE  EON The largest span...

GEOLOGIC TIME SCALE GEOLOGIC TIME SCALE A timeline that illustrates Earth’s history based on geologic events and lifeforms. This is a system that chronologically relates geological strata (stratigraphy) to time.  4 MAJOR DIVISIONS OF THE GEOLOGIC TIME SCALE  EON The largest span of the geologic time scale  TWO DIVISION EON OF EONS A. PRECAMBRIAN EON The largest span Refers to the earliest part of the geologic of Earth’s history. time scale B. PHANEROZOIC EON The current geologic eon in the geologic time scale. PRECAMBRIAN EON Hadean Eon Archean Eon Proterozoic Eon HADEAN EON Occurred 4.6 – 4 billion years ago. During this time, the solar system was forming within a cloud of dust and gas known as the solar nebula, which eventually formed planets, and other terrestrial bodies. HADEAN EON The earth started cooling and the outer edge of the planet solidified from molten lava to a solid crust. Water rained from the atmosphere and created ocean. ARCHEAN EON 4 – 2.5 billion years ago First life forms was created in the oceans ARCHEAN EON CYANOBACTERIA ▪ evolved at least 2. billion years ago ▪ Earth's first photosynthetic bacteria, using water and the Sun's energy, and releasing oxygen as a result. ARCHEAN EON By the end of the Archean, the ocean floor was covered in a living mat of bacterial life. PROTEROZOIC EON The “age of hidden life” Started 2.5 billion years ago Enough shield rock had formed to start recognizable geologic processes such as plate tectonics.  PROTEROZOIC EON Fossil remains of bacteria  PROTEROZOIC EON Blue-green algae  PROTEROZOIC EON First oxygen dependent animals – Ediacara fauna  PHANEROZOIC EON Abundance of animal and plant life existed Covers 541 million years to the present.  PHANEROZOIC EON Subdivided into three ERA PALEOZOIC ERA MESOZOIC ERA CENOZOIC ERA  PALEOZOIC ERA 542 – 251 million years ago Known as the “ancient life” It is characterized by the diversification of life on Earth, with the emergence of many major animal groups, including invertebrates, fish, amphibians, reptiles, and the first land plants. PALEOZOIC ERA Divided into Six Periods Cambrian Ordovician Silurian Devonian Carboniferous o Mississippian o Pennsylvanian Permian PALEOZOIC ERA Paleozoic Tectonic Events The Rodinia supercontinent break into the Laurentia and Gondwana land. Gondwana moved towards the southern pole Laurentia moved towards the equator and continued moving. At the late carboniferous period the continent collides to form Pangaea.  CAMBRIAN PERIOD Cambrian Explosion (541-485 million years ago) MAJOR EVENTS OF THIS PERIOD Predation Hard-Shelled Organisms o Trilobites – arthropods with hard exoskeletons o Brachiopods – Filter-feeding marine animals with two shells. o Crinoids - sea lilies, are related to starfish, sea urchins, and sea cucumbers  ORDOVICIAN PERIOD 485 – 444 million years ago Diversity of marine invertebrates, including mollusks, coelenterate, graptolites, trilobites, Eurypterid. Earliest vertebrates appeared (ostracoderms) First plants in land are Non – vascular plants (e.g., mosses, liverworts) ostracoderms  ORDOVICIAN PERIOD Major extinction event in which 60% of marine species were wiped out ended the Ordovician period.  SILURIAN PERIOD 443 – 416 million years ago First developed jaw fish (Placoderm) First plant appeared on land First terrestrial arthropods. Laurentia, Siberia, Baltica move toward each other at equator and started forming a 2nd supercontinent Euramerica Early Silurian glaciers melt and sea level rises toward end of Silurian (greenhouse effect) FIRST DEVELOPED JAW FISH (PLACODERM) First plant appeared on land – ORDOVICIAN FLORA First terrestrial arthropods – MILLIPEDES  DEVONIAN PERIOD 416 – 359 million years ago “Age of Fish” due to abundance of fish diversity First ferns on land as well as tree-like plants. Abundant marine life including bony fish. First seed bearing plants appeared. First ammonite appeared. FERNS FIRST SEED BEARING PLANTS AMMONITE  CARBONIFEROUS PERIOD 359 – 299 million years ago Forests and swamps with seed plants on land. Winged insects Early amphibians on land Fish expand in oceans, many mollusks and corals, but few trilobites. Inland seas reduced due to beginning collision of continents to form Pangaea ICHTHYOSTEGA - early amphibians on land  CARBONIFEROUS PERIOD Land dries due to changes in glaciation and Pangaea Episodes of mountain building takes place.  PERMIAN PERIOD Life in oceans diminishes First vertebrate herbivores on land Many gymnosperm plants 90% of marine species experience extinction at the end of the period. Warming climate, dry interior of continents. first vertebrate herbivores on land - Eocasea MAJOR EXTINCTION AND ICE AGES 1. Late Ordovician 2. Late Devonian 3. Late Permian and early Triassic The most important is Permian-Triassic extinction in which almost 90% species were destroyed and only few land species had survived. MESOZOIC ERA Divided into 3 Periods Triassic Jurassic Cretaceous  MESOZOIC ERA “Middle Life” 252 – 66 million years ago Known as the age of reptiles/dinosaurs. Life diversified rapidly and giant reptiles, dinosaurs, and other monstrous beasts roamed the Earth.  TRIASSIC PERIOD (252 – 200 million years ago) Rise of reptiles First dinosaurs walked on the land Late Triassic – early mammals appeared FIRST DINOSAUR – NYASASAURUS PARRINGTONI  JURASSIC PERIOD (200 – 145 million years ago) Dinosaurs dominated the land First appearance of BIRDS Pangaea began to break apart in early Jurassic period. Formation of the Atlantic Ocean First Flowering Plants – angiosperm First appearance of BIRDS - Archaeopteryx  CRETACEOUS PERIOD (145– 66 million years ago) Know for the dominance of iconic dinosaurs such as: Triceratops Tyrannosaurus rex Pterosaurs Angiosperm Dominance Marine Reptile Diversity Mammalian Diversification  Triceratops  Tyrannosaurus rex Pterosaurs CENOZOIC ERA Divided into 3 Periods Paleogene Neogene Quaternary  CENOZOIC ERA (65 million years ago – present ) The current locations of the continents and their modern-day inhabitants, including humans, can be traced to this period. “AGE OF MAMMALS” - due to extinction of many groups of giant mammals, allowing smaller species to thrive and diversify because their predators no longer exist.  PALEOGENE PERIOD (65 - 23 million years ago) The beginning of the Paleogene period was a time for the mammals that survived from the Cretaceous period. Later in this period, rodents and smaller horses (Hyracotherium) are common. Rhinoceroses and elephants appeared. End of the period – dogs, cats, and pigs become commonplace. rodents  NEOGENE PERIOD (23 – 2.6 million years ago) Gives rise to early primates, including early humans. Bovids, including cattle, sheep, goats, antelope, and gazelle, flourished during this period. Early Primates Bovids  QUATERNARY PERIOD (2.6 million years ago – present) Cave lions, sabretooth cats, cave bears, giant deer, woolly rhinoceroses, and woolly mammoths were prevailing species of this period.