Name _______________________________________________ Date ___________ Pd ______ Timeline Activity Objectives: • To understand the concept of a million and a billion • To model the geologic time scale • To use the analytical skills of measurement and scientific notation. • To compare the dynamic relationship between Earth’s conditions and the diversity of its organisms. Background: As you learn about past events in Earth history you may be surprised when you hear that something occurred ‘only’ a million years ago. In the context of a human lifetime this is an enormous amount of time. Yet geologists many consider this to be a short time ago when compared to the Earth’s age. The enormity of geologic time is difficult to understand. One way to help visualize geologic time is to create a time line. Note – while there are slight discrepancies among scientists over the exact dates of certain major events (ie: extinction of the dinosaurs), for the purposes of visualization our dates are accurate. Remember: 10 = 1,000,000,000 1 billion 106 = 1,000,000 1 million 5 10 = 100,000 1 hundred thousand 4 10 = 10,000 10 thousand 9 Materials: • Masking tape or sidewalk chalk • Event notecards (below) • • Long sidewalk or football field Measuring wheels, meter sticks Procedure 1. Distribute event cards without years on them to each student 2. Take students to the field and show them the formation of the Earth (4.6 bya) and today. 3. Ask students to arrange themselves on the field to represent the sequence of events. 4. Now gather the students and issue the same event cards with the years on them and ask students to calculate their event using the meter sticks/measurement wheels provided. (Note: it helps to have a few predetermined distances identified to save time). Warn students not to rely on the correct measurements of others or one wrong student can have a domino effect. 5. Once students have placed themselves correctly, have them mark their event/location with tape or sidewalk chalk. 6. Take students on a ‘field trip’ of geologic time, calling out events as they are encountered, briefly discussing each event as you pass. This is a great time to relate the significance of the environmental conditions of the planet to the life found at the time, and what contribution each event had to the development of the Earth as we know it today. Calculations (for football field): How do we translate history onto our field? 750 million years ago started the Paleozoic Era. Where would this fall on our field? 750 million years = 7.5 x 108 years 7.5 x 108 years x (1 yard) 5.0 x 107 years = 7.5 x 108 5.0 x 107 =7.5 5 x (108 – 107) = 1.5 x 101 = 15 yards Questions 1. Were you accurate on you approximation? When given the event date, was it earlier or later than you expected? 2. Why do you think it is so hard for humans to visualize a billion years? 2. The universe was formed approximately 13.7 billion years ago. Using the same scale, how far away would this be? Can you find a reference point? Extensions: This activity can be done (indoors) with a toilet paper roll indicating the history of Earth with students marking events with marker. Students can either be asked to predict events with blank cards or can be given premade (calculated) cards and asked to measure. Alternatively, the teacher can pre-identify the locations of the events and ask students to mark the place for the simplest visualization. http://www.eshirts.com/product_images/y/537/154301__35716_std.jpg Event Approximate Age A Formation of the Earth 4.6 billion years B Oldest known rock 4.3 billion years C First single-celled organism 4 billion years D Age of most continental crust 3.7 billion years E First viruses appear 3.5 billion years F Blue-green algae (1st to make O2) 3 billion years G First fungi appear 1 billion years H First multi-celled organism 700 million years I Precambrian Extinction (70% of all life wiped out) 650 million years J First shellfish appear 570 million years K First fish appear 510 million years L First true plants appear 498 million years M First sharks appear 390 million years N First amphibian appear 375 million years O First reptile appears 325 million years P Permian-Triassic Extinction (99% of all life wiped out) 250 million years Q Mesozoic Era begins 245 million years R First mammal appears 200 million years S Age of most oceanic crust 180 million years T First known bird appears 160 million years U Rocky Mountains formed 80 million years V Extinction of the dinosaurs 65 million years W First proto-humans appear 3.5 million years X Earliest modern humans appear 2 million years Y Last Ice Age 20,000 years ago Z Recorded human history begins 10,000 years Distance on Field Formation of the Earth Oldest Known Rock 1st Single-Celled Organism Age of Most Continental Crust First Viruses Appear Blue-Green Algae (First oxygen-producers) First Fungi Appear First Multi-Celled Organisms Precambrian Extinction (70% of all life wiped out) First Shellfish Appear First Fish Appear First True Plants Appear First Sharks Appear First Amphibian Appears First Reptile Appears Permian-Triassic Extinction (99% of all life wiped out) Mesozoic Era Begins (The Age of the Dinsaurs) First Mammal Appears Age of Most Oceanic Crust First Known Bird Appears Rocky Mountains Formed Extinction of the Dinosaurs First Proto-Humans Appear Earliest Modern Humans Appear Last Ice Age Recorded Human History Beings
