Geological Timeline Reflection

Earth's history is long and ever-changing, shaped by major events that altered Earth as we know it, but three major events were especially important in constructing the world we live in today. Probably the most important event, that allowed most if not all life to thrive, is the oxygenation of Earth which occurred about 2.3 billion years ago and was caused by the photoautotroph cyanobacteria. Oxygen produced by photosynthesis (cyanobacteria), helped to give rise to other organisms and eventually multicellular eukaryotes. In addition, the movement of arthropods onto land and eventually larger vertebrates was also a big event in Earth's history. Movement onto land led organisms thriving off the plants, eventually leading to more advanced organisms like reptiles and mammals. Finally, the evolution of mammals, specifically humans, was one of the most important events in the history of the Earth. Humans, Homo sapiens, have had one of the greatest impacts on the Earth in such a short time.

During the course of the geological timeline project, we had to observe and measure out the scale and size of Earth's history, and throughout this process, several things surprised me. First, is how long the Earth took to develop: the first bacteria/prokaryotes appeared about halfway through Earth's history and the first eukaryotic life forms appeared about 500-600 million years ago (Earth is 4.6 billion years ago). Another thing that surprised me was how short of time humans have been on the planet, so short in fact that it was impossible to mark how long humans had been on Earth on the geological timeline we made. Finally, another interesting thing I observed that is somewhat related to the scale of Earth's history, is how life has exponentially evolved in complexity so much that we as humans have only been here for about 200,000 years back to our oldest ancestor.

As I begin to observe the history of the Earth, I realized that humans have made such a big impact on the planet in such a small amount of time. Humans have been on the Earth for a micro-fraction of time, and yet we have become so advanced surpassing any other species in intelligence by a longshot. And yet we over the past 100 years, which is a blink of an eye in geological terms, we have also damaged the planet heavily with pollutants, causing global warming and other climate change issues. Earth has existed in the universe for 4.6 billion years, but the human race, which has only become civilized has caused more damage to the planet than any other organism that has ever existed on the planet. There have been a total of five mass extinctions in the Earth's history and if we don't do anything about it, there might be a sixth one.

First Experiment and Moving Forward (20 Time)

During the past few weeks, I have been working on my 20 time project with a steady pace. In addition to my research, I have done an experiment to test ways to lower blood pressure. I have taken a group of friends and ran them through some tests, such as playing video games, listening to music, etc. and see how these tasks affect their blood pressure. I got good results from the experiment and I might run some more tests on other people so I can get more data for my experiment. As a result of this experiment, I have learned about what simple tasks people with high blood pressure can do to lower their blood pressure. Although I have done this experiment, I plan, with the data I have gathered, to maybe do a longer term experiment and for a length of a few weeks to a month try to lower my blood pressure, recording my progress over the weeks. In order to do this, I can use the data from my previous experiment and other sources to determine what I can do to lower my blood pressure and increase my overall health. I hope that I can use the information I have gathered during 20 time to spread awareness about high blood pressure and potentially help others manage their health.

Unit 8 Reflection

 In Unit 8, we learned about the concepts of evolution and natural selection and how this affected and continues to affect ur world today. In order to have evolution, there are a few things that must be established. First, is variation, or differences in traits within a population, allowing, therefore, artificial selection, human breeding, or natural selection, the process of weeding out the not beneficial traits and letting individuals who have beneficial traits survive and reproduce. As a result, allele frequency begins to change, as natural selection weeds out the bad phenotypes, causing the population to evolve. Although natural selection is the most common cause of evolution, there are other causes of evolution, including genetic drift(a random event), gene flow(movement of alleles), mutations, and sexual selection(selecting for traits that improve mating success). Speciation, caused by reproductive isolation, is a result of evolution, as a species can be behavioral, geographically, or temporally isolated, eventually evolving until the two separate populations cannot reproduce. Even though evolution is a very reinforced theory, there is little evidence, only things like embryology, vestigial structures, and fossils like homologous or analogous structures give us proof of evolution. Throughout Earth's history from the Precambrian Era to the Cenozoic Era, evolution by natural selection has played a big role in creating the world we live in today.

During the course of the unit, I have been working on being more assertive as we learned in Unit 7. Throughout the unit, I have been working on speaking more clearly, louder, and generally more assertively. In addition, I have been trying to speak and share more in not just biology, but in other classes like English or math. Furthermore, I am also working on being more on improving my body language and I have also improved on my overall teamwork skills by working more assertively in a group. By the end of Unit 8, I was a lot more assertive than at the beginning of the unit and I hope to improve on my assertiveness as the year goes on.