Modeling the Geological Time Scale  
        HASPI MS Medical Earth Science Lab 02b 
         
        Scenario 
         
        The geological time scale marks major events that have happened throughout the history of the 
        Earth.  The Earth has changed significantly throughout time and it is estimated that 99.9% of all 
        organisms that have one time lived on Earth are now extinct.  By examining the fossil record 
        scientists can develop a range of time when a species, or group of species, lived and became 
        extinct.  In this activity you will create a model of the geological time scale to get a better idea of 
        when major events have occurred during Earth’s history. 
         
        Materials 
         
        Paper strip                             Scissors                    Ruler 
        Geological Event cards                  Tape                        Pen/pencil 
         
        Directions 
         
                                 Task                                                  Response 
        
           Cut and tape together 5 meters of paper strip. You will need 3 sheets of the “Time Scale” sheets 
      1 
           to make 5 meters. 
      2    Cut out the “Geological Event Cards.”  
           Lay out the 5-meter paper strip on the floor or in an open space.  Using a ruler, you will be 
           marking out and taping the geological event cards on the paper strip to create a model of the 
       
           geological time scale.  For this activity: 
       
       
                                                 1 mm = 1 million years 
      3 
                                                1 cm = 10 million years 
                                               10 cm = 100 million years 
                                                1 meter = 1 billion years 
           Each of the geological event cards has a                    
        
           description and a date.  Starting with the card with 
      4 
           the most recent date titled “Present.”  Tape the 
           “Present” card at the very beginning of the paper 
           strip. 
           Find the next most recent geological event card. 
           For example, it should be the “Cenozoic Era Start” 
        
           at 65 million years.  Using the ruler, measure 6.5 
      5 
           cm from the first card.  Make a mark on the paper 
        
           strip and tape the “Cenozoic Era Start” card in 
           place at the mark.  
           Continue finding the next most recent geological event card and continue measuring and taping 
      6    the cards in place.  Remember that every date and measurement should start from the 
           BEGINNING of the paper strip. 
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                Geological Time, the Fossil Record, & Health; HASPI MS Medical Earth Science Lab 02 
                                                                  
                                                                  
                                                                  
       7    Once complete, answer the following questions based on your geological time scale model. 
            When did the Earth              
       8    begin?                          
                                            
            When did life first appear      
       9    on Earth?                       
                                            
            When have most of the           
       1    major events on Earth 
       0    occur? 
            What era are we currently   
       1    in?                             
       1                                    
            In what era did dinosaurs       
       1    and mammals appear?             
       2                                    
            In what era did insects         
       1    and reptiles appear?            
       3                                    
            Why do you think the            
            appearance of oxygen in 
       1    the atmosphere was 
       4    important? 
             
            Notice that the dinosaur        
            extinction led to an 
         
            increase in mammals. 
       1
            How do you think this 
       5 
            has shaped the 
            organisms currently living 
            on Earth? 
            In what habitat did most        
            life exist during the 
         
            Paleozoic era?  Explain 
       1
            your answer. 
       6 
             
             
            The first humans                
            appeared approximately 
            200,000 years ago.  If the 
       1    Earth is 4.6 billion years 
       7    old, what percentage of 
            time have humans been 
            on the Earth? 
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                Geological Time, the Fossil Record, & Health; HASPI MS Medical Earth Science Lab 02 
                        Why is it important to                                              
                        study the history of the                                            
              1         Earth?                                                              
              8                                                                             
                 
                                                                                                 Geological Event Cards 
                                                                                Modeling the Geological Time Scale 
                                                                                          HASPI Medical Earth Science Lab 02b 
                                                                                                                                         
                                                                         Cut out each of the following cards on the dotted line 
                                                                                                                                         
                                   Present                                        Beginning of Earth                                           Mesozoic Era Start                                          Dinosaur Extinction 
                                                                                                                                                                                                                                     
                                                                       
                                                                                                                                                                                                                                                                
                                                                                                                                                                                                   
                                                                                                                                      
                             Current Date 
                                                                                                                                                                                                                  66 million years 
                                                                                                                                                   245 million years 
                                                                                       4.6 billion years 
                   Cambrian Explosion                                                      Earliest Life                                            First Mammals                                            First Land Animals 
                                                                                                                                                                                                                                     
                                                                                                                                                                                                    
                                                                                                                                     
                                                                                                                                                                                                                                                                   
                                                                  
                                                                                                                                                   200 million years 
                                                                                       3.8 billion years 
                                                                                                                                                                                                                430 million years 
                        542 million years 
                             First Insects                                              First Primates                                                First Reptiles                                           First Land Plants 
                                                                        
                                                                                                                                                                                                                                                       
                                                                                                                                                                                                   
                        400 million years 
                                                                                                                             
                                                                                                                                                                                                                450 million years 
                                                                                                                                                   300 million years 
                                                                                       85 million years 
                                                                                  Oxygen in Atmosphere 
                       Oceans/Continents 
                                                                                                                                                Eukaryotes Evolve                                                        First Fish 
                                                                                                           
                                                                                                                                                                                                                                     
                                       Form 
                                                                                                                                                                                                                                                                 
                                                                                                                                      
                                                                                                                                                                                                                                     
                                                                                                                                                                                                 
                                                                                       2.4 billion years                                                                                                        500 million years 
                                                                    
                                                                                                                                                    1.8 billion years 
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                                 Geological Time, the Fossil Record, & Health; HASPI MS Medical Earth Science Lab 02 
           4.4 billion years 
                                                           Cenozoic Era Start 
        Paleozoic Era Start       First Amphibians                                     First Birds 
                                                                    
                                            
                                                      
                                                                               
                                            
                                                                                                         
                              
                                                            65 million years 
                                   360 million years 
                                                                                    150 million years 
          540 million years 
        
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              Geological Time, the Fossil Record, & Health; HASPI MS Medical Earth Science Lab 02