Geologic Timeline Reflection

        This unit, I worked in a group and created a geologic timeline of the history of the Earth. The timeline gave a sense of the magnitude and major events of the past, as well as how insignificant of a time we humans have occupied. I have organized some thoughts below as a sort of reflection on the project and what we learned.

Mesozoic Era and the K-T extinction

         In the Earth's history, some significant events were the oxygen revolution, Cambrian explosion, and K-T extinction. The oxygen revolution, which occurred in the Proterozoic Eon, had a lasting and important impact on the Earth. Scientists have found that there was a radical increase in oxygen levels due to the photosynthetic actions of cyanobacteria; it has been estimated that the amount of oxygen went from 1% to 15% of current levels, and changed. Thus, this event affected the future of the Earth and made possible the proliferation of oxygen-respiring organisms afterward. The Cambrian explosion was also one of the most important events: it consisted of a burst of immense evolution and diversification that took place in an "explosion." The organisms arose in a mere 30 million years, and began many of the lineages that persisted for millennia, and that we see today. This was the cause of the development of both terrestrial flora and fauna, but also the marine life of the Ordovician and Devonian Periods. Lastly, the K-T extinction was highly influential to the development of the following Cenozoic Era. It saw the extinction of all dinosaurs and many other species, and allowed the adaptive radiation of the unaffected species and organisms, such as mammals. Thus, it made possible much of what exists today, including our own species, that would otherwise not have risen to such a degree.

Cenozoic Era and the blink of an eye that is us

        The scale of Earth's history is simply colossal, what with our own written and evolutionary history not even a blink of an eye in the planet. Though I had some idea of this comparison, especially as I had researched the topic as part of my 20 Time project, I was unaware of the vast difference of the eons and epochs. That said, we have had a surprising impact on the planet during our relatively short time here: we have changed the climate, the temperature, the geography, the topography; we have decimated many species, and allowed others to become widespread to further our own ends; we have spread and sought in space, and plumbed the deepest trenches of the Earth. As much as we have learned, we have destroyed, and there is no question that we will continue to do so. Perhaps through this, we are our own demise; just another species that formed, thrived, and died out as it made way for others to dominate. Are we just another Dinosauria? In all the ways we think ourselves superior, certain adaptations bequeathed similar advantages upon other species of the past. Flight, camouflage, speed, different senses: they all shone through and thrived, though the species changed and diverged. Are we different from all that came before us? What will come after us? Will we ever know? Perhaps not. But that is, inherently, our advantage: the unceasing yearning to know, to learn, to grow.