This assignment requires answering questions based on the exhibit “The Earliest Traces of Life” at the Smithsonian Museum of Natural History, Washington, D.C. The exhibit that you are to see is on the right side as you enter the Rotunda from Jefferson Street. Enter the exhibit hall under the dinosaur banner. As you go through this doorway, the exhibit is located to the right. For additional information on the location, hours, ect., go the museum web site at www.mnh.si.edu and click on the Information desk link.
Study the exhibit and answer the following questions. Submit your answers in Blackboard. Please view the short movie that comes along with the exhibit.
1. How abundant was oxygen in the early atmosphere? The amount of oxygen in the atmosphere was abundant, however, due harmful radiation waves from the sun, photosynthetic systems such as plants were not able to evolve thus leaving the state of oxygen subtle. 2.What evidence do scientists have that the oxygen content of our atmosphere has increased since the earth’s origin?
The O-zone layer is composed of 3 oxygen atoms formed after photosynthetic organisms release an extra oxygen molecule into the atmosphere.
2. Why is oxygen more abundant in the atmosphere today?
Because of the high amount of plants that produce oxygen which were not here in the early stages of life on earth 3. What are stromatolites? Stromatolites are the bindings of microorganisms on rocks and stones, usually submerged underwater, these rocks are usually used as samples for the earliest signs of life 4. What do scientists think is implied by the presence of stromatolites in Precambrian rock? Scientists would conclude that life was formed underwater and the process of evolution eventually allowed multi-cellular organisms to make their way off the ocean and/or bodies of water. 5. What is ozone and how is it produced?
The o-zone layer is the protective layer made of 3 oxygen atoms, it is usually formed by the extra oxygen resulted from a photosynthetic organism. 6. Why is ozone important to life today?
Because it protects us from ultra-violet rays from the sun which are extremely harmful and sometimes fatal to all life forms. 7. What effect did increased levels of oxygen in the atmosphere have on early life forms? It caused organisms that were not light and/or oxygen dependent to disappear as mammals and other multi-cellular organisms began to take over.