Presentation on theme: "The Geological Time Scale"— Presentation transcript:
1The Geological Time Scale 8-2.4 Recognize the relationship among the units—era, epoch, and period—into which the geologic time scale is divided.8-2.5 Illustrate the vast diversity of life that has been present on Earth over time by using the geologic time scale.8-2.2 Summarize how scientists study Earth’s past environment and diverse life-forms by examining different types of fossils (including molds, casts, petrified fossils, preserved and carbonized remains of plants and animals, and trace fossils).8-2.3 Explain how Earth’s history has been influenced by catastrophes (including the impact of an asteroid or comet, climatic changes, and volcanic activity) that have affected the conditions on Earth and the diversity of its life-forms.
2Events in Your Life ___When you started second grade 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)___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.___ Today’s date.
5What is the Earth’s time scale? The Geological time scale is a record of the life forms and geological events in Earth’s 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.
11FOUR Eras… PRE-CAMBRIAN – 88% of earth’s history Paleozoic (ancient life)544 million years ago…lasted 300 million yrsMesozoic (middle life)245 million years ago…lasted 180 million yrsCenozoic (recent life)65 million years ago…continues through present day
12Today…Today we are in the Holocene Epoch of the Quaternary Period of the Cenozoic Era.Which unit is the largest?Which unit is the smallest?
13Today…Today we are in the Holocene Epoch of the Quaternary Period of the Cenozoic Era.Which unit is the largest?Which unit is the smallest?
15Paleozoic Era (Ancient Life) The Cambrian period is the 1st period of the Paleozoic Era. “Age of the Trilobites”Explosion of life in the oceans began during this era.Most of the continents were covered in warm, shallow seas.Invertebrates were dominate - TrilobitesFish emerged during this timeFish led to the arrival of amphibiansThe end of the Paleozoic era is called the “Age of Amphibians”Early land plants including mosses, ferns and cone-bearing plants.The early coal forming forests were also formed during this time.
16Paleozoic 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.
17Paleozoic 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
18Trilobites Lived in Earth’s ancient seas Extinct before the dinosaurs came into existenceCambrian Period is know as the “Age of the Trilobites” (put in on table)
24Mesozoic Era – Middle Life At 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 shells
25Mesozoic Era Dinosaurs 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.
29Mesozoic EraThe main plant life of this time were Gymnosperms or plants that produce seeds, but no flowers.Pine TreesFlowering plants appeared during the END of this era.
30Mesozoic 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.
36Mesozoic Era – Mass Extinction Event Asteroid 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.
41Mesozoic PlantsFlowering plants evolved towards the end of the Mesozoic Era.
42Cenozoic Era – Recent Life Began 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 animalsMany mountain ranges formed during the Cenozoic EraAlps in Europe and Himalayas in India; Rocky Mountains in the USA
43Cenozoic 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 Mammals”
44Cenozoic Era Marine animal examples: Land animal examples: Algae, Mollusks, Fish and MammalsLand 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.
46Flowering Plants were common during the Cenozoic Era
47Life forms found in each Era On your worksheet,:- List Geologic Events found ineach Era.- List Life forms found in each Era.- Draw pictures of Life Forms…USE COLOR!Make sure you are putting them in the correct block!!