On Friday, we had a presentation on the Geological Timeline of Earth. It was extremely exciting because Connie had so much experience and knowledge. She explained how Earth was “born” through the time that Humans evolved. Connie is a hydrogeologist, which means that she studies the Earth by looking at water.
Connie took us through a very interesting timeline that showed us the Earth’s past and also explained how people can tell what points in time are marked by different kinds of rock. Different sediments get pressed together to form a rock which can be measured by where they are in relation to one another, almost like a natural timeline. The same is true of ice! Connie used two ropes to illustrate the length of time that the Earth has existed – the longer one represented the time on Earth before living creatures appeared, and a shorter one that represented the time when biological entities existed on Earth. We were surprised that the shorter string represented the time with life, because it’s still a very very long time, but the time without life was so much longer!
Connie used an excellent resource, which you can look at here: http://science.nationalgeographic.com/science/prehistoric-world/prehistoric-time-line/
This timeline is interactive and shows lots of information and images that helped us understand different points in history through the appearance and extinction of different creatures that have lived on Earth including those who disappeared before Humans arrived. Dinosaurs are an example of some of the species that suffered mass extinction. We know that they existed and became extinct because of the fossil record, and the fact that there is an abundance of fossils in one layer, while in the layer above (closer to the surface), there are almost none. We also talked about how features on the Earth’s surface appeared, and how the continents have changed over time. We learned about mountain building and Pangea.
Pangea was a supercontinent which was a combination of the continents we know today. When the continents were conjoined the species spread out and the animals were seperated onto the different continents. This is the reason why we find animals such as spiders, all over the world.
Connie inspired us with a great idea for a timeline, and we really enjoyed her presentation.
By PointyHegdehog11 and Mario02