...how these conditions were created. Surfaces of Mars, Moon, Venus, Earth. Source: NASA Sections: 1. Introduction 2. Many Planets, One Earth 3. Reading Geologic Records 4. Carbon Cycling and Earth's Climate 5. Testing the Thermostat: Snowball Earth 6. Atmospheric Oxygen 7. Early Life: Single-Celled Organisms 8. The Cambrian Explosion and the Diversification of Animals 9. The Age of Mammals 10. Further Reading Unit 1 : Many Planets, One Earth -1- www.learner.org 1. Introduction Earth's long history tells a story of constant environmental change and of close connections between physical and biological environments. It also demonstrates the robustness of life. Simple organisms first appeared on Earth some 3.8 billion years ago, and complex life forms emerged approximately 2 billion years ago. Life on Earth has endured through many intense stresses, including ice ages, warm episodes, high and low oxygen levels, mass extinctions, huge volcanic eruptions, and meteorite impacts. Untold numbers of species have come and gone, but life has survived even the most extreme fluxes. To understand why Earth has been so conducive to life, we need to identify key conditions that make it habitable and ask why they exist here but not on neighboring planets. This unit describes how Earth's carbon cycle regulates its climate and keeps surface temperatures within a habitable range. It also examines another central factor: the rise of free oxygen in the atmosphere starting more than...
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...Early Predictions of Climate Change From the time of the ancient Greeks through the 19th century to present day, the effects that humans have on the earth’s climate have been studied. Scientists have been able to track the earth’s climate change through out history. In the 1930s a noticeable warming trend was noticed compared to the average temperature in the 19th century. Guy Stewart Callendar, an English engineer, studied the changes in the climate and concluded that the human emissions of carbon dioxide gas could lead to the “greenhouse effect”. “With a new awareness that climate could change in serious ways, in the early 1970s some scientists predicted a continued gradual cooling, perhaps a phase of a long natural cycle or perhaps caused by human pollution of the atmosphere with smog and dust” (Weart, 2003-2010). The concept of the “greenhouse effect” was first introduced in 1896 by Swedish scientist Svante Arrhenius. Together with Thomas Chamberlin, Arrhenius “calculated that human activities could warm the earth by adding carbon dioxide to the atmosphere” (Enzler, 2004, para 1). While a supply of natural greenhouse gases are needed to maintain a sustainable climate, in which humans can survive, too much was predicted to cause a blanket that traps the heat in the earth’s atmosphere. The trapped heat was believed to result in a rise in temperature. According to Environmental Defense Fund, “Even if the temperature change is at the small end of the predictions, the alterations...
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...Before we begin to explore the earth’s layers from core to atmosphere and the materials that it is composed of, we will need to look at the earth’s early stages of formation. Included in this is will be; what materials the earth is comprised of, as well as; how they arrived on the earth, and the resulting heat energy that is inherent within our earth. When the earth was still in its early stages of formation it was slowly accumulating mass from particles within the planetary rings that were attracted by the earth’s gravitational pull. These particles were metallic chunks; similar to iron meteorites, rocky chunks; similar to stony meteorites, and icy-gaseous chunks; similar to comets. As these particles collided with the earth it created stored heat energy through kinetic energy, we call this impact energy. With every impact the earth’s mass increased and the gravitational pull became stronger contracting in on itself which added more heat energy that we refer to as gravitational energy. Radioactive energy, or radioactivity, is when an unstable particle collides with the earth and break down to something stable and gives off heat energy. These three types of heat energy are inherent to the earth’s composition and are key when looking at the various layers that make up our earth. With all the inherent heat energy that the earth has, it causes the various materials that collide with earth to heat up as they are pulled toward the center of earth’s mass. This causes the various...
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...) • First evidence for early life • The evolution of life • Extreme life on Earth: lessons for astrobiology A timeline for the very early history of the Earth The formation of Earth: The Earth formed over ~50 Myr via planetesimal accretion Earth differentiation: The iron "drops" follow gravity and accumulate towards the core. Lighter materials, such as silicate minerals, migrate upwards in exchange. These silicate-rich materials may well have risen to the surface in molten form, giving rise to an initial magma ocean Early Earth heats up due to radioactive decay, compression, and impacts. Over time the temperature of the planet interior rises towards the Femelting line. After the initial segregation into a central iron (+nickel) core and an outer silicate shell, further differentiation occurred into an inner (solid) and outer (liquid) core (a pressure effect: solid iron is more densely packed than liquid iron), the mantel (Fe+Mg silicates) and the crust (K+Na silicates). Initially large portions of the crust might have been molten - the so called magma ocean. The latter would have cooled to form a layer of basaltic crust (such as is present beneath the oceans today). Continental crust would have formed later. It is probable that the Earth’s initial crust was remelted several times due to impacts with large asteroids. The formation of Earth: Delivery of water by icy planetesimals and comets? After condensation of water vapor produced the earth's oceans, thus sweeping...
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...Avatar Pandora is an Earth-like moon that is a host to life. It has a very similar but different biosphere compared to that of the Earth’s. It has twenty percent less gravity than Earth making the proportional scale several times larger than Earth’s, the animals, the plants, everything is huge in comparison to the Earth. The atmosphere on Pandora is made up of nitrogen, oxygen, carbon dioxide, xenon, ammonium, methane, and hydrogen sulfide. The carbon dioxide and the hydrogen sulfide are non-breathable for humans, this is why they humans have the wear oxygen masks (exopacks). Pandora is a very biodiverse locale. It has its own functioning ecosystem with a unique fauna and flora. Some characteristics of Pandora’s flora are that it is made up...
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...Geology Notes Origin of Planet Earth and Solar System: * Earth as a unique planet 1. Presence of a “hydrosphere”/ there’s liquid water/ makes life possible 2. Presence of a life supporting atmosphere/ there’s oxygen: not too much, not too little (too much oxygen results in fires) 3. Distance from the sun/ controls overall temperature of planet, Goldilocks Zone: not too hot, not too cold/ also controls composition of planet * Terrestrial Planets- Mercury, Venus, Earth, Mars, Asteroid Belt (all relatively small and rocky) * Jovian Planets- Jupiter, Saturn, Uranus, Neptune (huge and gaseous) 4. Size- Dictates gravitational pull (larger body= more gravity)/ gravity holds in atmosphere/ 2 most abundant gasses are hydrogen and helium/ cooling rate of planet- over time interior of planets cool down (smaller planet cools quicker, larger planet cools slower) 5. Presence of an internal heat engine- breakdown of radioactive substances gives off heat, causing interior of Earth to be hot/ due to internal heat engine, we have: earthquakes and volcanoes (most abundant material ejected form volcanoes is water * Basic observations of our solar system 1. Jovian vs. Terrestrial planets 2. All planets revolve around sun in same direction 3. All planets and our sun are coplanar/ lie along same imaginary surface in space 4. All planets and our sun have a common age of formation, 4.6 billion years ago The Nebular Hypothesis: Formation of solar system ...
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...2014 How Plate Tectonics affected Thailand In the early 20th century, there was a theory developed by meteorologist Alfred Wegener that proposed that all of the continents had once been connected in a single supercontinent called Pangaea. The theory of Plate Tectonics is the theory that the rigid layer of the lithosphere is divided into a couple of dozen plates that move around across the Earth’s surface relative to each other, like slabs on a lake. In geologic terms the word “plate” means a large slab of solid rock and “tectonics” means to build. The words together define how the Earth’s surface is built up of moving plates. The theory says the Earth’s lithosphere is made up of individual plates that are broken into over a dozen large and small pieces of solid rock. The fragments ride next to each other on top of the Earth’s lower mantle that has more fluid. It creates different types of plate boundaries that haves shaped the Earth’s landscape over millions of years. Wegener believed the continents gradually began to drift apart about 300 million years ago. This theory became known as Continental drift. (PBS online 1997) On December 26, 2004 a 9.0 magnitude quake struck under the Indian Ocean near West Coast of the Indonesian Island of Sumatra affecting as many as 150,000 dead or missing people and leaving millions homeless. The vast speeds caused by the violent movement of sections in the Earth’s crust known as Tectonic Plates. This deadly quake sent an...
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...Old-Earth Geology and its Ramifications for Life in the 21st Century” by Dr. Terry Mortenson. Overview In Dr. Terry Mortenson’s article, “The Origin of Old-Earth Geology and its Ramifications for Life in the 21st Century”, the subject of Earth’s creation and age is briefly discussed. Several contributors to the theories behind the history of earth are introduced, along with their respective backgrounds. Dr. Mortenson explains the geological findings and resulting theories of each contributor regarding: the age of the earth, evolution, catastrophic events and their relationship of science to Christianity. (Mortenson, 2003) Strengths The importance of the history of science, especially relating to Christianity, is expressed early in the reading. Readers are also cautioned regarding views on evolution and creation and the consequences of those views (social, moral, spiritual) (Mortenson, 2003). Dr. Mortenson expresses the Christian mindset towards the creation of earth and mankind in a series of six 24 hour days, along with a detrimental flood accompanying Noah around 1600 years later. The author further presents that in the late 1700’s the non-Biblical history of earth began to theorized and become popular. The developing field of geology in early 19th century is introduced, along with those whose research became important through its study. Dr. Mortenson makes note of earlier French works (Epochs of Nature (1778), Exposition of the System of the Universe (1796), and Zoological...
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...What is the most significant set of theories that explain the evolutionary history of our natural world and ongoing environmental change? The origin of life and earth is still one of the greatest mysteries scientists have yet to solve. Modern day science and technology allow us to make theoretically correct assumptions about the past. According to research, it is evident that the earth’s environment and life have been evolving since the beginning of time, which is still evident today as ecosystems and environments continue to change. Three theories that help explain the evolutionary history of our natural world and ongoing environmental change include natural selection, neutral theory of molecular evolution, and the transition into the Anthropocene epoch. Natural selection theory argues that life forms evolve in response to the changes in the environment. Neutral theory of molecular change argues that changes occur in organisms at a constant rate over time without the influence of the environment. Anthropocene is a relatively new term that suggests we have transitioned from the Holocene era to the Anthropocene, which is characterized human dominated activity. These theories are presented in various works, but this paper will focus on Life and the Evolution of Earth’s Atmosphere by Stephen J. Mojzsis, The Anthropocene: a new epoch of geological time? by Jan Zalasiewicz, Mark Williams, Alan Haywood, and Michael Ellis, and The Modern Molecular Clock by Lindell Bromham and David...
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...A massive explosion with more energy than the atomic bombs dropped in World War II ripped through the sky as a huge chunk of rock traveling close to fifty-thousand miles per hour was overpowered by the sheer force of aerodynamics and exploded into oblivion (Tagliaferri, 1998). This explosion was an asteroid from space that was on a collision course with the earth; in February of 1994 the asteroid struck. “The asteroid actually broke into several pieces, with one large piece detonating about 34 km above the surface, and a second, much larger piece detonating at an altitude of approximately 21 km” (Tagliaferri, 1998). Scientists were lucky to record this data via satellite to study the force an asteroid can have when impacting firsthand. There is evidence of asteroid impacts covering the surface of the earth and other surrounding planets in space. There are also many theories involving asteroid impacts causing mass extinctions on Earth, the most common being the extinction of the dinosaurs 65 million years ago (deGrasse Tyson, 2005). Most of the impact evidence shows that the earth has been attacked by these asteroids since its formation billions of years ago. Evidence all around us tells us that the Earth will be struck, and another major asteroid impact will occur. The most common and highly argued impact event is the one that may have wiped out the dinosaurs. This event in itself has many theories, but the one common element in most sound dinosaur extinction theories is that...
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...Telescopes in Astronomy Cary Lingle PHY 107 June 25, 2013 Professor Worek Telescopes in Astronomy Peering out beyond the confines of the Earth was a daydream for early scientists. Staring into the heavens from the Earth limited the scientific community’s ability to study the cosmic bodies above the Earth’s surface. As curiosity grew to explore the Sun, moon, stars and far-reaching corners of the universe, creativity was sparked leading to the development of tools like a telescope to assist scientists with examining outer space and its contents. The development of the telescope began in the hands of a Dutch lens maker, Hans Lippershey. Lippershey developed a device consisting of a tube and a lens allowing the user to view objects up close. Galileo Galilei expanded upon Lippershey’s design creating the modern day telescope using a concave lens. Galileo used his telescope view the items in the night sky including the Milky Way. Galileo revealed that the Earth was not at the center of the universe that was a contrasting view from previous scholars. The development of the telescope has lead to significant discoveries including the moon's effect on weather patterns on Earth and in space black holes, stars' lifecycles and galaxies beyond the Milky Way to name a few. The ability to study the Sun has given scholars the ability to determine the age of the Sun, planets and stars in the night sky. The first telescope's original design, consisting of a tube and lens, gave the viewer...
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...University of Phoenix Material Environmental Movement Matrix Choose five items from the following list and identify their significance during the 1970s: |Cuyahoga River, OH (Cleveland) fire 1969 |Conservationism vs. environmentalism | |Love Canal |Acid rain | |Silent Spring |Ozone layer | |Population Bomb |Rainforests | |Endangered Species Act (1966, 1969, & 1973) |Depletion of fossil fuels | |Clean Water Act (1972, 1977) |Climate change | |Event |Significance | |Silent Spring |Written by Rachel Carson, Silent Spring was a book that had a huge influence on the decision to ban DDT in the | | |United States in 1972 (Brinkley, 2012). Unlike most pesticides, whose effectiveness is limited to destroying | | |one or two...
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...Global Warming Global warming has been one of the most fervently debated and scientifically challenging topics of the 21st century. According to NASA, as early as 1904, Swedish scientist, Svante Arrhenius, was among the “first persons acknowledged to investigate the effects of doubling atmospheric carbon dioxide and how this would affect the global climate”. (1) As technology and scientific studies progressed throughout the 1900’s and into the 21st century, the effect of human civilizations on climate change was thrust into public spotlight. While fluctuations in the earth’s climate is a natural phenomenon, the vast amount of greenhouse gases expelled into the environment due to anthropogenic influence likely enhances, or acts as a catalyst, for overall climate change. Numerous studies exist that show increases in carbon dioxide levels throughout history via direct sampling as well as ice core analysis. In 1957, “Charles Keeling began measurements of atmospheric carbon dioxide from an observatory on the Mauna Loa volcano in Hawaii. He soon identified what became known as the ‘Keeling Curve’ – a graph that showed atmospheric concentrations of carbon dioxide increasing year by year.” (2) A quick view of the Keeling Curve, even by the untrained eye, shows a strong correlation between human industrialization and the sudden increase in greenhouse gases, See Figure 1. While the increases in CO2 alone does not point to human intervention, the clearly recognizable rise in...
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...The author of the article " When Did Photosynthesis Emerge on Earth?” is David J. Des Marais. The author examines the period when photosynthesis emerged and the issues surrounding its emergence in our biosphere. The author looks at the historical and evolutionary evidence to advance the topic of the emergence of photosynthesis. The article is majorly based on the biosphere changes and the changes in the oxygen levels and the metamorphosis of sedimentary rocks to illustrate the sequence of biochemical records and trends. In the early Earth’s history photosynthesis has highly evolved. Also through the rapidity of its emergence has suggested that there was no existence of flukes and it could also on other worlds also (Des Marais, 2000). The question on when did photosynthesis take its place in the place Earth is an issue which has been researched widely in order to unearth the many unknown mysteries. Probably life is thought to have begun early the history of the Earth, perhaps more than 3800 years ago and through the years it has received a lot of sophistication in terms of metabolism. Great developments of biomolecules and key pathways reveal a great deal of evolutional innovations in the field of photosynthesis. A sequence of genes’ information has been used in the analysis of the major photosynthetic bacteria. Also the molecular origins of the major photosynthetic bacteria has been clarified to a great extent (Des Marais, 2000). There is a vast base of evidence defending the...
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...1 Online vs. Traditional Education COM/156 June 3, 2012 2 Climate Cylcles Inexplicable weather changes, devastating tsunamis, earthquakes in unusual places, seasons seemingly being skipped or prolonged, floods amongst several other abnormalities in the way the world we know have been occurring more frequently, more powerfully and more frighteningly. As humans, naturally we question, fear and seek to explain all of these deadly and destructive anomalies. Some claim an apocalypse is coming, some say we are heading toward an ice age, some believe we have accelerated a change in the Earth’s climate cycles by our own actions. Any view taken, is one of fear and trepidation. As a factual and unbiased paper, we will not take the Apocalypse theory into account for the fact that there are concrete facts or evidence. Regardless of why we believe something is wrong or changing, it is undeniably fact that the world is changing on many levels. The purpose of this paper is explore and attempt to find the reasons why this is happening, and what we, as mankind, can do to be prepared, and to attempt to mitigate any effect we may have on the acceleration of these changes Pollution and human consumption of fossil fuels, trees and other natural resources have been the scapegoat for “global warming” for several years now. How is it that, specifically, carbon emissions from vehicles allegedly has caused or sped the rate of global warming? Carbon emissions have been in existence since...
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