HOLY ANGEL UNIVERSITY High School Department #1 Holy Angel Avenue, Sto. Rosario, Angeles City ACTIVITY SHEETS Name ___________________________________________ Year and Section ____________________________ Subject: GRADE 11 – Earth and Life Science ACTIVITY: (Please check the appropriate box) Concept Notes Laboratory Report Skills/Drill/Exercise Drawing/Art/Plate Grade/Score _______________ Date ______________________ Physical Sciences Formal Theme Journal Informal Theme Quiz Others ___________ ACTIVITY TITLE: Article Analysis No.1 LEARNING TARGET: Traces of ancient life found in fossils could date back 3.7 billion years By Los Angeles Times, adapted by Newsela staff on 03.08.17 Word Count 873 Rocks that are 3.7 billion years old and were found on the shore of Hudson Bay in Quebec, Canada, may hold the oldest-known fossils on Earth. If they are actually fossils, that is. The scientists who found them believe that they are fossils. If they are right, it could mean that life on Earth began within 200 to 500 million years of the birth of the planet 4.5 billion years ago. “These findings show that life managed to emerge and evolve very rapidly on Earth,” said Matthew Dodd. Dodd is a graduate student at the University College London. He is the first author of a study about this new finding. It was recently published in the journal Nature. Fossils are records of prehistoric organisms, or living creatures. They can be either the actual remains of a creature, or just its imprint, embedded in rock. Dodd says the creatures in the fossils his team found appear to be quite complex. “That means we’re not even at the origin of life yet,” he said. Rocks Are Billions Of Years Old The discovery was made in rocks collected from the Nuvvuagittuq supracrustal belt in Quebec, Canada. The oldest rocks from this area date back nearly 3.8 billion years. They may even go back as far as 4.3 billion years. Supracrustal rocks are metamorphic rocks which were deposited on the earth's crust, its outermost layer, long ago. Supracrustal rocks are metamorphic rocks, meaning they changed form over time. They were once both sedimentary and volcanic rocks. Sedimentary rocks formed from particles left from large movements of water or ice on the earth's surface, such as glaciers. Volcanic rocks were formed from the hot substances that once erupted from volcanoes. Dominic Papineau is a geochemist and astrobiologist also at University College London and a co-author on the paper. He collected palm-sized rock samples from the site back in 2008 and brought them back to the lab for further study. The team sliced the rocks into sections about 30 microns in width. This was thin enough to see light shining through them. With the aid of a microscope, the researchers were able to map the minerals in each slice. After that, they scanned the side of the rocks with a laser. This gave them an even finer view of the chemistry inside. Tubes May Have Been Made By Living Creatures Previous work had already revealed that the iron formations in the Nuvvuagittuq belt had chemical patterns similar to those found in seawater. Other clues suggested they formed near hydrothermal vents, openings in the sea floor where heated water flows out. That water is rich with minerals. The authors identified microscopic tubes and filaments, which are tiny threads, embedded in the Nuvvuagittuq rocks. Some of them were attached to clumps of iron. The authors think the filaments look remarkably similar to tiny fossils found in some much younger rocks. Those fossils were found near hydrothermal vents in Norway and off the coast of California. The team says the filaments from the Nuvvuagittuq belt rocks are similar in size and shape to filaments in microbes or bacteria found today in low-temperature ocean vents. These vents are known to have bacteria which live off of iron nearby. Dodd says this suggests that the creatures in his fossils would have lived in a similar way to modern bacteria that live off of iron. Controversial Conclusions Dodd knew these conclusions would be controversial. So he and his co-authors looked for further evidence to support their case that what they found truly represents traces of ancient life. There are other clues that the tubes and filaments were made by living creatures. One is the presence of granules inside the rocks that contain carbon-rich material. Similar granules are often seen in fossils in younger rocks, the authors wrote. The researchers said they considered all the possible ways these structures could have formed without the help of a living creature. He says no other scenario for how these structures formed could unite all the evidence he's found. “The only thing that can do that is the biological explanation,” Dodd said. Not Everyone Is On Board With Findings Some experts disagree. One of them is Martin Van Kranendonk, an early life researcher and head of the School of Biological, Earth and Environmental Sciences at the University of New South Wales in Australia. Van Kranendonk does not believe that what Dodd and his team have found are fossils. He says the authors of the study themselves said the features they described might have come from fossils that have a biological origin, but did not necessarily have to. “The reality is, we have no idea of how the structures formed or why,” he said. Exciting Implications If Study Is Correct If the authors are correct, though, the implications are thrilling. Just six months ago, another team of scientists found evidence of life that formed in shallow pools of water at roughly the same period. If both findings are proven correct, that means life was flourishing on Earth when it was still a very young planet. “The fact that these organisms emerged so quickly suggests to us that life may not be so complicated a process as we think,” Dodd said.
