Geologic_Time


 * ISB Bio 2: __Geologic Time__**

Our planet’s history extends back in time 4.5 billion years (4,500,000,000… wow!). This number is so large that it is challenging to grasp the tempo and timing of evolution on this planet. You will construct a miniature timeline as a way to visualize the appearance of specific organisms on the planet.
 * Part I:** __Making Sense of Time and Scale__

Your timeline will include the following chronological (that means timing) units: · Billion year markers that extend from the present to 5 billion years ago · The Formation of the Earth · The four Eras: Precambrian, Paleozoic, Mesozoic, and Cenezoic · Three key Periods: Triassic, Jurassic, and Cretaceous · Three key Epochs for Humans: Pliocene, Pleistocene, and Holocene

Your timeline will also include a label for the following eight organisms · 1st life (prokaryotes) · 1st eukaryotes · 1st multicelled life · 1st animals · 1st land plants · 1st Dinosaurs to Dinosaur extinction · 1st mammal · 1st human ancestor (Hominids)

Procedure 1. Obtain a strip of paper. 2. Measure 400mm from one end & use a scissor to cut off the excess. 3. Now draw a vertical line at each billion-year mark. To determine the location of these lines divide 400mm by 5:

400mm ÷ 5 = 80mm

Place your billion-year mark at 80mm intervals __You now know that 1 billion years = 80mm on the timeline__

4. Place a line at 4.5 billion years and label it “Earth Forms.” 5. Now determine the number of years that is represented by each mm on your timeline.

80mm = 1,000,000,000 years

1mm = (1,000,000,000 ÷ 80) = __ years

6. Using these sources, [|Evolution: Deep Time] and [|Evolving Planet], determine when each of the Eras, Periods, and Epochs (listed above) occurred. Now place these events on your timeline by drawing a vertical line at the appropriate spot and include a label. 7. Determine when each of the organism events (listed above) occurred. Place a vertical line in the appropriate spot and include a label.

Darwin brought several small journals on his voyage on the //Beagle.// Later he transferred the observations and thoughts from his journals to a larger document that he published under the title //The Voyage of the Beagle.// You will create a journal entry of a specific geologic time period for planet Earth. Although you cannot really go back in time, you can study fossil and rock records to arrive at an understanding of these ancient environments. In this activity, you will learn more about an ancient environment through your Web research. How old are you today? The Earth is about 4.6 billion years old. In this activity you will create a "Geologic Birthday Card." To do this, you need to figure out when you were born in geologic terms. In other words, if all of geologic time were compressed into one year, during which time period does your birthday fall? This task involves solving ratio problems. If you need help, see below for an example. 1.Divide the age of the Earth by the number of days in a year. 2.Next add the number of days from the beginning of the year until your birthday. (Include January 1st and your birthday.) 3.Subtract this number of days from the total number of days in a year. Geologic time is recorded in terms of millions of years ago (MYA). It counts back from the present. 4.Figure out the equivalent number of years on the [|geologic time scale]. 5.Round off to the nearest million years. 6.Visit the Deep Time Web activity and the Web Geological Time Machine to find out the name of the geologic time period that corresponds to this year. [|Deep Time] (Flash) [|Low-Bandwidth Version] 8.Be prepared to share your card with your classmates or display it in the classroom.
 * Procedures**
 * Part II: Happy Birthday, Earth!**
 * Part II: Happy Birthday, Earth!**
 * Your resources for this exploration are the Deep Time Web activity and the [|Web Geological Time Machine] at the University of California, Berkeley Museum of Paleontology Web site, each of which describes how the Earth has changed over 4.6 billion years. ||
 * || [[image:http://www.pbs.org/wgbh/evolution/library/03/4/images/l_034_48_m.gif width="160" height="120" caption="external image l_034_48_m.gif"]] ||
 * 7.Now that you know your geologic birthday, use these Web resources to study this time period. Design a birthday card for the Earth at that time. Your card should convey something about that time period -- the environment, the presence or absence of life, the arrangement of continents, and anything else you learn about that time. Be creative. You may want to compose a poem or use pictures from the Web site or a magazine.
 * See An Example:** ||  ||

//Adapted from: http://www.pbs.org/wgbh/evolution/educators/lessons/lesson3/act1.html//