Geological Timeline Reflection

We recently did a project where we created a timeline that represented the events that happened in Earth's history. This timeline went from the Hadean era to the present.

There were many important events over Earth's history, but some are more important than others. The three most important events are the creation of life, the mass extinctions, and the evolution of humans. It is rather self explanatory why the creation of life is important, because it led to every living thing on Earth. Life was created sometime during the Precambrian era, where the oldest prokaryotic fossils were found. It isn't known how life was created, but there are various theories and hypotheses, such as that the first amino acids came on a meteorite. Without life being created, the Earth would be a barren rock like some of the other planets. Like the creation of life, mass extinctions completely changed the Earth. They killed off lots of species, and caused new species to become dominant. In the Cretaceous period, half of plants and animals were killed off from a meteor. Humans may not have become the dominant species if this didn't happen. Humans have changed the Earth dramatically in the short time we have been here, which makes the evolution of our species one of the most important events in Earth's history. We have increased global temperatures, destroyed ecosystems, and are the cause of the next mass extinction. Without humans, none of this would have happened, and the planet would be in a lot better shape.

When we learned how long the Earth had existed, I had trouble picturing how long of a time it actually was. Most of the time on Earth was spent without life on it, and humans have been around for an extremely short time compared to the rest of Earth's history. What surprised me is how long Earth really has been around, about 4.6 billion years. This is a third of the universe's 13.7 billion year old existence. I found it interesting that the Earth was that old compared to the universe.

A diagram showing the events in Earth's history

As mentioned previously, humans have greatly impacted the Earth in the short time we have been here. We are causing the 6th mass extinction. We need to stop harming the planet, because even in the short time we have been here, we have drastically changed the Earth. For more detail on the issues facing the planet, check here. We have quickly become the dominant species on our planet, and have started changing other species to benefit us. We have bred animals to create different breeds, and we have genetically modified species to do many different things, like plants that are resistant to insects. A certain type of bacteria evolved to decompose plastic created by human activity. Despite the minuscule time we have been on the planet, we have changed a lot.

The only remaining questions that I have are ones that can't be answered. How was life created on Earth? If it came from a meteor, how was that life created? Someday, these questions may be answered, but we can only hypothesize until then.