Geologic time

Geologic timeHow do we know when things happened?1GoalsStudents will write about, talk about, and understand the principles of relative dating and original horizontality(7A)Students will write about, talk about, and understand the principle of Radiometric dating 7B)Students will write about, talk about, and understand the scale and scope of the Geologic time scale2Part 1With a partner of your choosing, answer the questions from the end of the packet I hand out. Alternate answering the questions on you answer page. Skip questions 1 and 15.Match vocabulary words to the questions to help find answers if you are having trouble with one. 2-4. 2645. 2666-9. 264-910-12. 270-27313-14. 274-27517,18. 277-9, 2813Events in Your Life___When you started second grade___When you were born___ When you started kindergarten___When you learned to ride a bike.___ When you learned to walk.___ When you learned to read.___ When you lost your first tooth.___ Todays date.Construct a timeline of the important events in your life. Be sure to include all of the events listed below and any other events you feel are important. Your timeline should be constructed TWO ways:Numerical Order (use actual dates)Sequential Order (most recent at top)4

5What is the Earths time scale?The Geological time scale is a record of the life forms and geological events in Earths history. Scientists developed the time scale by studying rock layers and fossils world wide.Radioactive dating helped determine the absolute divisions in the time scale.

66Divisions of Geologic TimeEras are subdivided into periods...periods are subdivided into epochs.

Era

Period

Epoch

E + P = EP

77Divisions of Geologic TimeGeological time begins with Precambrian Time. Precambrian time covers approximately 88% of Earths history.

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9FOUR ErasPRE-CAMBRIAN 88% of earths history

Paleozoic (ancient life)544 million years agolasted 300 million yrs

Mesozoic (middle life)245 million years agolasted 180 million yrs

Cenozoic (recent life)65 million years agocontinues through present day1010TodayToday we are in the Holocene Epoch of the Quaternary Period of the Cenozoic Era.

Which unit is the largest?Which unit is the smallest?1111

12Paleozoic Era (Ancient Life)The Cambrian period is the 1st period of the Paleozoic Era. Age of the TrilobitesExplosion of life in the oceans began during this era. Most of the continents were covered in warm, shallow seas.Invertebrates were dominant - TrilobitesFish emerged during this timeFish led to the arrival of amphibians The end of the Paleozoic era is called the Age of AmphibiansEarly land plants including mosses, ferns and cone-bearing plants.The early coal forming forests were also formed during this time.13TrilobitesLived in Earths ancient seasExtinct before the dinosaurs came into existenceCambrian Period is know as the Age of the Trilobites

14Paleozoic EraMuch of the limestone quarried for building and industrial purposes, as well as the coal deposits of western Europe and the eastern United States, were formed during the Paleozoic.

The Cambrian (beginning) opened with the breakup of the world-continent Rodinia and closed with the formation of Pangaea, as the Earth's continents came together once again. This event is thought to have caused the climate changes that led to mass extinction event.The Appalachian mountains were formed during this time.15Paleozoic EraAt the end of the Paleozoic, the largest mass extinction in history wiped out approximately 90% of all marine animal species and 70% of land animals.Possible causes of this Mass Extinction EventLowering of sea levels when the continents were rejoined as Pangaea (convergent boundary)Increased volcanic activity (ash and dust)Climate changes cooler climate

16Brachiopods

Marine animals that resemble clams.17Early Fish

Early fish did not have jaws.Some species of sharks were in existence at this time.

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Frilled Shark that was found in Japan in January 2007. This shark was considered a living fossil19Early Land Plants

Cone bearing plantsFernsMosses20Mesozoic Era Middle LifeAt the beginning of this era the continents were joined as Pangaea. Pangaea broke up around the middle of this era.Reptiles became the most abundant animals because of their ability to adapt to the drier climate of the Mesozoic Era.Skin maintains body fluidsEmbryos live in shells21Mesozoic EraDinosaurs were also very active in this era.First small dinosaurs appeared in the Triassic Period.Larger and more abundant dinosaurs appeared in the Jurassic Period.Small mammals and birds also appeared during this era.The mammals were small, warm-blooded animals. Hair covering their bodies.These characteristics help them survive in changing environments.22

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25Mesozoic EraThe main plant life of this time were Gymnosperms or plants that produce seeds, but no flowers. Pine Trees

Flowering plants appeared during the END of this era.26Mesozoic EraThis era ended with a mass extinction event about 65 million years ago.Many groups of animals, including the dinosaurs disappeared suddenly at this time.

Many scientists believe that this event was caused by a comet or asteroid colliding with the Earth.27

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31Mesozoic Era Mass Extinction EventAsteroid or Comet collides with Earth.

Huge cloud of smoke and dust fills the airBlocks out sunlightPlants dieAnimals that eat plants dieAnimals that eat plant-eaters die.

However, not all forms of life died during this event. Many animals that you see today are descendants from the survivors of this extinction event.

32Dinosaurs

33Mesozoic Reptiles

34Mesozoic Mammals

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36Mesozoic Plants

Flowering plants evolved towards the end of the Mesozoic Era.37Cenozoic Era Recent LifeBegan about 65 million years ago and continues today!!!!!Climate was warm and mild.Marine animals such as whales and dolphins evolved.

Mammals began to increase and evolve adaptations that allowed them to live in many different environments land, air and the sea.Grasses increased and provided a food source for grazing animals

Many mountain ranges formed during the Cenozoic EraAlps in Europe and Himalayas in India; Rocky Mountains in the USA38Cenozoic EraGrowth of these mountains may have helped to cool down the climateIce Ages occurred late in the Cenozoic Era (Quaternary Period).

As the climate changed, the animals had to adapt to the rise and fall of the oceans caused by melting glaciers.

This era is sometimes called the Age of Mammals39Cenozoic EraMarine animal examples:Algae, Mollusks, Fish and Mammals

Land animal examples:Bats, Cats, Dogs, Cattle and HumansHumans are thought to have appeared around 3.5 million years ago (during the most recent period Quaternary).

Flowering plants were now the most common plant life.

40Cenozoic Mammals

41Flowering Plants were common during the Cenozoic Era

42Test ThursdayWe will spend tomorrow reviewing the material from the last 3 weeks.43