GEOLOGIC TIME Earths History Divided into 4 eras

Earth’s History • Divided into 4 eras • • Precambrian Paleozoic Mesozoic Cenozoic •

PRECAMBRIAN ERA • 4. 6 BYA - 540 MYA • 4, 060, 000 YEARS

PRECAMBRIAN ERA • Earth’s atmosphere contained: • • • Hydrogen cyanide Carbon dioxide Carbon

PRECAMBRIAN ERA • 4 BYA Earth’s surface cooled enough for rocks to form •

MILLER/UREY EXPERIMENT • Tried to answer how life first formed on Earth • They

PRECAMBRIAN ERA • 3. 5 BYA, unicellular prokaryotic organisms • Evolved in the absence

PRECAMBRIAN ERA • Oxygen was a deadly poison to the first cells • With

PRECAMBRIAN ERA • Endosymbiotic Theory • 2 BYA Prokaryotic cells began evolving internal cell

PRECAMBRIAN ERA • Sexual reproduction of eukaryotic cells occurs • Allows for genetic variation

PRECAMBRIAN ERA IN A NUTSHELL • Began with no oxygen in the atmosphere, ended

PALEOZOIC ERA • 540 MYA-245 MYA • 295, 000 YEARS LONG! • Made up

PALEOZOIC ERA • Lots of fossil evidence • Early in the era, there was

PALEOZOIC ERA • First vertebrates formed • Jawless fish • Some arthropods moved to

PALEOZOIC ERA • Ended with a mass extinction • Affected both land sea organisms

MESOZOIC ERA • 245 MYA-66 MYA • 179, 000 YEARS LONG! • AGE OF

MESOZOIC ERA • Warm and Moist Environment • Pangea formed near beginning • Drifted

MESOZOIC ERA • Ended with another mass extinction! • ½ of all the plants

CENOZOIC ERA • 66 MYA AGO-PRESENT • 66, 000 YEARS LONG AND COUNTING! •

CENOZOIC ERA • Mammals that survived the extinction of the Mesozoic Era evolved adaptations

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GEOLOGIC TIME

Earth’s History • Divided into 4 eras • • Precambrian Paleozoic Mesozoic Cenozoic • Era’s divided into Periods • Periods divided into epochs http: //www. precisiongraphics. com/portfolio/animation/

PRECAMBRIAN ERA • 4. 6 BYA - 540 MYA • 4, 060, 000 YEARS LONG! • Makes up 88% of Earth’s History • Longest era

PRECAMBRIAN ERA • Earth’s atmosphere contained: • • • Hydrogen cyanide Carbon dioxide Carbon monoxide Nitrogen Hydrogen Sulfide Water (gas) • Notice: Oxygen was not a main component

PRECAMBRIAN ERA • 4 BYA Earth’s surface cooled enough for rocks to form • 3. 8 BYA Earth’s surface cooled even more, allowing water to remain in a liquid state • Constant thunderstorms • Oceans covered most of the Earth’s surface

MILLER/UREY EXPERIMENT • Tried to answer how life first formed on Earth • They simulated Earth’s atmosphere combined with lightening storms, which they found produced AMINO ACIDS! • Amino acids are necessary for life • Not accurate, but on the right track!

MILLER/UREY EXPERIMENT

PRECAMBRIAN ERA • 3. 5 BYA, unicellular prokaryotic organisms • Evolved in the absence of oxygen • Over time, photosynthetic bacteria formed • Remember oxygen is released during photosynthesis • Accumulations of oxygen in the atmosphere caused it to turn blue and the ozone to form • Protection from solar radiation • Took several hundred million years to reach the oxygen levels we have today

PRECAMBRIAN ERA • Oxygen was a deadly poison to the first cells • With the increase of oxygen on Earth, many organisms died off, while other new ones formed. The new ones were able to process this oxygen and survive. • Beginning of evolution!

PRECAMBRIAN ERA • Endosymbiotic Theory • 2 BYA Prokaryotic cells began evolving internal cell membranes (early eukaryotes) • Prokaryotes entered these early eukaryotes and lived inside of them! • Mitochondria and chloroplasts are what used to be prokaryotic cells that could use oxygen and carry out photosynthesis who lived inside these early eukaryotes • Mitochondria and chloroplasts today contain DNA similar to bacteria! EVIDENCE!

PRECAMBRIAN ERA • Sexual reproduction of eukaryotic cells occurs • Allows for genetic variation • Faster than asexual reproduction by prokaryotes • Multicellular eukaryotic organisms developed • • Simple aquatic plants Sponges Flatworms Jellyfish

PRECAMBRIAN ERA IN A NUTSHELL • Began with no oxygen in the atmosphere, ended with oxygen in the atmosphere • Life only in the oceans • Anaerobic organisms formed, but many became extinct later when photosynthetic organisms evolved and produced oxygen (which was deadly to the anaerobic organisms). From this, aerobic organisms formed. • Prokaryotes formed first, then eukaryotes • Few fossils were found from this era • Soft bodied, hard to form fossils

PALEOZOIC ERA • 540 MYA-245 MYA • 295, 000 YEARS LONG! • Made up of 7 Periods

PALEOZOIC ERA • Lots of fossil evidence • Early in the era, there was a diversity of marine life • Cambrian Explosion! • Age of the Invertebrates • Jellyfish, worms, sponges, brachiopods, trilobites

PALEOZOIC ERA • First vertebrates formed • Jawless fish • Some arthropods moved to live on land • Insects • First land plants • Ferns • AGE OF THE FISHES-Devonian Period • First amphibians, then reptiles

PALEOZOIC ERA • Ended with a mass extinction • Affected both land sea organisms • Many fish and reptiles survived • Cause is unknown for the mass extinction • Theory-volcanic explosions? • Theory-global climate change?

MESOZOIC ERA • 245 MYA-66 MYA • 179, 000 YEARS LONG! • AGE OF THE REPTILES • Made up of 3 Periods

MESOZOIC ERA • Warm and Moist Environment • Pangea formed near beginning • Drifted near the end • Flowering Plants Evolved • Organisms-lizards, turtles, crocodiles, snakes, birds • DINOSAURS!!! • Mammals first appeared

MESOZOIC ERA • Ended with another mass extinction! • ½ of all the plants and animals died off • ALL THE DINOSAURS BECAME EXTINCT • Cause unknown • Meteor?

CENOZOIC ERA • 66 MYA AGO-PRESENT • 66, 000 YEARS LONG AND COUNTING! • Made up of 2 Periods • Ice Age separates the two periods • AGE OF THE MAMMALS

CENOZOIC ERA • Mammals that survived the extinction of the Mesozoic Era evolved adaptations that allowed them to live in various environments • Land, water, air • Organisms-dolphins, whales, cattle, deer, sheep • 4. 5 MYA is the earliest fossil of ancient human • Ardipithecus ramidus • 120, 000 years ago-Homo sapiens • Human Evolution took about 4, 380, 000 years!