In the 1990s, I found the dating issue enthralling and saw it assailed by fringe theorists and by . A couple of decades later, I reached the understanding that, like all sciences, dating has its limitations and the enthusiasm for a new technique can become a little too exuberant, but dating techniques and technologies have greatly improved in my lifetime. Dating the , and using 100,000-year increments to place the dates, may seem a conceit, thinking that scientists can place that event with that precision, but over the years my doubts have diminished. When and can be tested, and the findings support not only Earth’s age previously determined by myriad methods, but also support the prevailing theories for the solar system’s and Moon’s formation, call me impressed. Controversies will persist over various finds and methods used, and scientific fraud certainly occurs, but taken as a whole, those converging lines of independently tested evidence make it increasingly unlikely that the entire enterprise is a mass farce, delusion, or even a conspiracy, as many from the fringes continue to argue. There is still a , and it is not a parody. I have looked into fringe claims for many years and few of them have proven valid; even if many were, their potential importance to the human journey was often minor to trifling. As the story that this essay tells comes closer to today’s humanity, orthodox controversies become more heated and fringe claims proliferate.
The greatest scientists readily admitted that the theories and data of physics, that hardest of the hard sciences, drew highly limited descriptions of reality, and those scientists were usually, to one extent or another, . If textbook science falls far short of explaining reality, what can be said within its framework that is useful? Plenty. Our industrialized world is based on textbook science and feats such as putting men on the Moon were performed within the parameters of textbook science. With the waning of overspecialization and overreliance on reductionism in the last decades of the 20th century, multidisciplinary works have proliferated and will tend to dominate the references for this essay. I have found them not only very helpful for my own understanding, but they are appropriate references for a generalist essay. I have also avoided scientific terminology when feasible. For example, I use “seafloor” instead of “,” and if a non-specialized term will suffice for a scientific concept, I will often use it.
I am taking some liberties in calling Turkana Boy a ; he is technically a member of , which is often considered ancestral to , which is the Asian variant’s name. There is great debate regarding how the human family tree branches between and . Some call the various -type species all subspecies of , while others argue for several distinct species. I will not stray far from the orthodox narrative here, for good reason. The reconstructed early human tale is based on very limited evidence, but that evidence will only grow over time, and the tools and techniques for using them will become more sophisticated. Although there may be some upcoming radical changes in the view of the early human journey, efforts of countless scientist and fossil hunter lifetimes support the narrative that this essay sketches, and I respect their findings and opinions, even though I acknowledge many limitations. The human ego, it seems, becomes more involved as the story of life on Earth moves closer to its human chapters.
Perhaps the most damaging deficiency in FE efforts, after self-serving orientation, was that the participants and their supporters were scientifically illiterate and easily led astray by the latest spectacle. Scientific literacy can help prevent most such distractions. While writing this essay, I was not only bombarded with news of the latest FE and alternative energy aspirants' antics, but I had to continually field queries regarding whether Peak Oil and Global Warming were conspiratorial elite hoaxes (or figments of the hyperactive imaginations of environmentalists and other activists), for two examples that readily come to mind. Digesting this essay's material should have those questions answered as mere side-effects. Far from being a hoax or imaginary, Peak Oil was and , and it is all downhill from there, and conventional oil will be almost entirely depleted in my lifetime. , although both were heavily promoted in the USA in 2014. In every paleoclimate study that I have seen, so-called greenhouse gases have always been considered the primary determinant of Earth's surface temperature (after the Sun), and carbon dioxide is chief among them. The radiation-trapping properties of carbon dioxide are not controversial in the slightest among scientists, and after the Sun's influence (which is exceedingly stable), declining carbon dioxide levels are considered to be the conditions that have dominated Earth for the past 35 million years. Humanity's increasing the atmosphere's carbon dioxide content is influencing the cause of Icehouse Earth, and , and are merely proximate causes. Increasing carbon dioxide can turn the global climate from an to a Greenhouse Earth, and the last time that happened, Earth had its . But have purposefully confused the issues, and a scientifically illiterate public and have played along, partly because believing the disinformation seems to relieve us all of any responsibility for our actions. Although scientific literacy can help people become immune to the disinformation and confusion arising from many corners, and reading this essay's first half can help people develop their own defense from such distractions, my goals for this essay's first half are far greater than that.
But the branch of the that readers might find most interesting led to humans. Humans are in the phylum, and the last common ancestor that founded the Chordata phylum is still a mystery and understandably a source of controversy. Was our ancestor a ? A ? Peter Ward made the case, as have others for a long time, that it was the sea squirt, also called a tunicate, which in its larval stage resembles a fish. The nerve cord in most bilaterally symmetric animals runs below the belly, not above it, and a sea squirt that never grew up may have been our direct ancestor. Adult tunicates are also highly adapted to extracting oxygen from water, even too much so, with only about 10% of today’s available oxygen extracted in tunicate respiration. It may mean that tunicates adapted to low oxygen conditions early on. Ward’s respiration hypothesis, which makes the case that adapting to low oxygen conditions was an evolutionary spur for animals, will repeatedly reappear in this essay, as will . Ward’s hypothesis may be proven wrong or will not have the key influence that he attributes to it, but it also has plenty going for it. The idea that fluctuating oxygen levels impacted animal evolution has been gaining support in recent years, particularly in light of recent reconstructions of oxygen levels in the eon of complex life, called and , which have yielded broadly similar results, but their variances mean that much more work needs to be performed before on the can be done, if it ever can be. Ward’s basic hypotheses is that when oxygen levels are high, ecosystems are diverse and life is an easy proposition; when oxygen levels are low, animals adapted to high oxygen levels go extinct and the survivors are adapted to low oxygen with body plan changes, and their adaptations helped them dominate after the extinctions. The has a pretty wide range of potential error, particularly in the early years, and it also tracked atmospheric carbon dioxide levels. The challenges to the validity of a model based on data with such a wide range of error are understandable. But some broad trends are unmistakable, as it is with other models, some of which are generally declining carbon dioxide levels, some huge oxygen spikes, and the generally relationship between oxygen and carbon dioxide levels, which a geochemist would expect. The high carbon dioxide level during the Cambrian, of at least 4,000 PPM (the "RCO2" in the below graphic is a ratio of the calculated CO2 levels to today's levels), is what scientists think made the times so hot. (Permission: Peter Ward, June 2014)
Mass extinction events may be the result of multiple ecosystem stresses that reach the level where the ecosystem unravels. Other than the meteor impact that destroyed the dinosaurs, the rest of the mass extinctions seem to have multiple contributing causes, and each one ultimately had an energy impact on life processes. The processes can be complex and scientists are only beginning to understand them. This essay will survey mass extinction events and their aftermaths in some detail, as they were critical junctures in the journey of life on Earth.
For this essay’s purposes, the most important ecological understanding is that the Sun provides all of earthly life’s energy, either (all except nuclear-powered electric lights driving photosynthesis in greenhouses, as that energy came from dead stars). Today’s hydrocarbon energy that powers our industrial world comes from captured sunlight. Exciting electrons with photon energy, then stripping off electrons and protons and using their electric potential to power biochemical reactions, is what makes Earth’s ecosystems possible. Too little energy, and reactions will not happen (such as ice ages, enzyme poisoning, the darkness of night, food shortages, and lack of key nutrients that support biological reactions), and too much (such as , ionizing radiation, temperatures too high for enzyme activity), and life is damaged or destroyed. The journey of life on Earth has primarily been about adapting to varying energy conditions and finding levels where life can survive. For the many hypotheses about those ancient events and what really happened, the answers are always primarily in energy terms, such as how it was obtained, how it was preserved, and how it was used. For life scientists, that is always the framework, and they devote themselves to discovering how the energy game was played.
Efforts have been made in the paper to describe role of science in daily life. Importance of science in my life has been highlighted and thoughts have been presented of my becoming a scientist. Science, in fact, has benefited us in almost every area of life and has changed our entire course of life.
Another important area of our daily life is fast and convenience methods of traveling. The advent and invention of new as well as innovative ways of traveling have enabled us to cover huge distances in a very short span of time. Airplanes and railways have made the journey, thanks to science, comfortable, safe, convenient, and swift. In fact, world has shrunk to become a global village in which distances do not matter.
Scientists are working continuously to serve humanity by increasing their control over world and its environment. Scientific knowledge makes us understand as to how continuous changes have caused the oceans and atmosphere to transform, altering the climate of world. Science supports us in controlling the main source of our being- food and water. Science, in our daily lives, is a huge blessing of God as it relieves us from ignorance, pain, and feeling of distress. It provides us the opportunity to control our world, acquire wisdom, and gain knowledge through valuable inventions. It is, in fact, providing precious service to human beings, only if we use it instead of misusing it. Science has changed entire course of human life. Although, it is a fact that everybody is not able to reap benefits of science, yet the comfort created by it benefits everyone, to some more, while for others less. In daily life, for example, it is necessary to communicate with each other including friends, relatives, colleagues etc. We need to contact several persons during routine life. Through mobiles, wireless, telephones, and internet, it has become immensely easy to communicate with each other even in seconds. Cheap methods of entertainment are available to us through scientific innovations. For example in music, science has opened new avenues of enjoying life at a very low cost. Radios, cinemas, televisions, DVDs, and different other modes of entertainment has opened new doors of recreation as well as effective modes of communications. Life of human beings today is, therefore, significantly different compared to almost a decade ago and this continuous change will be affecting and altering our daily lives in the future.