APEC Schools Wiki: How Does Earth Support Life? PDF

WIKI: HOW DOES EARTH SUPPORT LIFE? Earth, our home planet, is a world unlike any other. The third planet from the sun, Earth, is the only place in the known universe confirmed to host life. With a radius of 3,959 miles, Earth is the fifth largest planet in our solar system, and it's the only o...

WIKI: HOW DOES EARTH SUPPORT LIFE? Earth, our home planet, is a world unlike any other. The third planet from the sun, Earth, is the only place in the known universe confirmed to host life. With a radius of 3,959 miles, Earth is the fifth largest planet in our solar system, and it's the only one known for sure to have liquid water on its surface. Earth is also unique in terms of monikers. Every other solar system planet was named for a Greek or Roman deity, but for at least a thousand years, some cultures have described our world using the Germanic word “earth,” which means simply “the ground.” Earth is unique because it is the only place in the universe known to host life. Some of the oldest evidence of microbial life suggests that it was already widespread on our planet 3.95 billion years ago. What makes Earth sustainable for life? It is the right distance from the Sun, it is protected from harmful solar radiation by its magnetic field, it is kept warm by an insulating atmosphere, and it has the right chemical ingredients for life, including water and carbon. The processes that shape the Earth and its environment constantly cycle elements through the planet. This cycling sustains life and leads to the formation of the mineral and energy resources that are the foundation of modern technological society. Let’s discuss the factors one by one. a. Moderate Temperature Range The distance of the Earth from the Sun gives the planet the favourable temperature condition. (Image Source: Sharp, T., & Urrutia, D. E. (2022, January 21). How far is Earth from the sun? Space.Com. https://www.space.com/17081-how-far-is-earth-from-the-sun.html) ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 1 of 9  The Earth and the Sun are equally important because the Earth would be a lifeless ball of ice-coated rocks without the Sun's heat and light. It regulates the temperature of water bodies, weather patterns, and provides energy to the growth of plants. The distance of the Earth from the Sun makes it a perfect reason for life because it receives the perfect amount of heat and light to allow life to be created and to support it. b. Presence of Water Water is very important for life because it contains the oxygen needed for life and allows life-providing molecules to move around easily. It continually changes its form through the water cycle. The process by which water continually changes its form and circulates between oceans, atmosphere, and land is known as the water cycle. (Image source: E. (2022, May 12). How Much Water Is on Earth? Earth How. https://earthhow.com/how-much-water-is-on-earth/) Earth's global ocean, which covers nearly 70% of the planet's surface, has an average depth of about 2.5 miles (4 kilometers) and contains 97% of Earth's water, while the 3% is freshwater that consists of ice-cap, groundwater, freshwater lakes, inland, and salt lakes. c. Favorable Atmosphere Near the surface, Earth has an atmosphere that consists of 78% nitrogen, 21% oxygen, and 1% other gases such as argon, carbon dioxide, and neon. ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 2 of 9  It is the layers of gases surrounding the earth that consists of the exosphere, thermosphere, mesosphere, stratosphere, and troposphere. The air content and favorable atmospheric pressure also supported the life of most creatures. The air content of carbon dioxide on the Earth is less than that of planets like Venus and Mars. Hence, the less air content of carbon dioxide helps moderate the Earth's temperature and is absorbed by plants during photosynthesis to produce oxygen. The atmosphere affects Earth's long-term climate and short-term local weather and shields us from much of the harmful radiation coming from the Sun. The ozone layer is a part of Earth's atmosphere situated in an area known as the stratosphere, which protects life on Earth from its potentially harmful effects of shorter wavelengths and highly hazardous ultraviolet radiation (UVR) from the sun. d. Availability and Use of Energy from the Sun Earth is the only planet that uses the Sun’s light as useful as a source of energy. That energy is used to convert elements, by living things, into a useable form. A plant uses the energy provided by the sun to drive photosynthesis and provide food to grow. As a by-product, oxygen is released, which we then use as an energy source of our own. (Image Source: https://www.researchgate.net/figure/The-annual-average-energy-striking-the-Earth-from-the-sun-is-relatively-constant-at-430_fig2_303370977) ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 3 of 9  e. Nutrients All solid planets & moons have the same general chemical makeup, so nutrients are present. However, only Earth has a water cycle and volcanic activities that can transport and replenish the chemicals required by living organisms. (Image Source: Hadrami, A. E. (2021, November 15). Blog. OMEX Agriculture Inc. https://omexcanada.com/blog/16-essential-elements) f. Magnetic Field The interstellar cloud of gas and dust that gave rise to Earth contained enough radioactive elements to power a churning core for billions of years. This creates a magnetic field that protects the planet from dangers like solar flares. ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 4 of 9  (Image Source: Nickel Is Crucial for Earth’s Magnetic Field. (2022, May 18). (C) 2014. https://www.geologyin.com/2017/07/nickel-is-crucial-for-earths-magnetic.html) The Sun's gravitational pull keeps our planet orbiting the Sun and the Earth firmly holds everything from topography to all life forms through its gravitational pull. The force of gravity doesn’t just keep us anchored to the ground but also affects our biological system. Aside from these conditions, Earth is also comprised of four major subsystems. These are also called the “spheres of the Earth,” namely, the atmosphere, hydrosphere, geosphere, and biosphere. a. Atmosphere The envelope of gas surrounding our planet Earth, known as the atmosphere, is organized into five distinct layers. These layers start at ground level, are measured at sea level, and rise into what we call outer space. ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 5 of 9  (Image Source: Earth's Atmosphere: A Multi-layered Cake. (2019, October 16). Climate Change: Vital Signs of the Planet. https://climate.nasa.gov/news/2919/earths-atmosphere-a-multi-layered-cake/#:) ➔ Troposphere. All life on this planet is affected by the changes that happen in this layer, as all the weather changes take place in the troposphere. It starts from the ground (or sea level) of our planet and expands up to 10 km up in the sky. The higher we go in this layer of the atmosphere, the ‘’thinner’’ the air gets, meaning it is significantly harder for us humans to breathe. ➔ Stratosphere. This layer goes up around 50 km above the Earth’s ground. In this layer, the temperature rises as you go further up, and it has something to do with the ozone layer that is found inside the stratosphere. ➔ Mesosphere. The air in this layer is absolutely not friendly for us, as it would be impossible to breathe in the mesosphere because of too low oxygen levels. Also, this layer of the atmosphere has the lowest temperature of all layers, and they drop down to -90° C. ➔ Thermosphere. This layer is under constant attack from the X-rays and UV radiation coming from the Sun and the space around us. Because of this, the temperatures in this layer can even reach 2,000° C. ➔ Exosphere. It is around 100,000 km, but it can expand up to 190,000 km above sea level. The air here is extremely thin, and the conditions here are more ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 6 of 9  similar to the ones we find when we leave the Earth’s atmosphere entirely. b. Hydrosphere The water on Earth is constantly moving. It moves through the oceans in currents. Warm waters in the tropics move toward the poles, while cold water from the polar regions moves toward the tropics. Water also flows into streams and rivers and through the rocks underground. It can also move from the Earth’s surface to the air by evaporation and then fall back to Earth as precipitation. It even moves into and out of the bodies of organisms. (Image source: E. (2022, May 12). How Much Water Is on Earth? Earth How. https://earthhow.com/how-much-water-is-on-earth/) c. Geosphere Geosphere includes all the soil, rocks, and minerals present in the crust to the core of the Earth. It is divided into three layers, namely crust, mantle, and core. (Image Source: Pascal, L. (2018, April 23). The Layers Of The Earth. ITEN Teacher Resource Center. https://www.oas.org/ext/en/development/teacher-education-resources/Lesson-Plans/Details/ArtMID/2125/ArticleID/1461/The-Layers-Of-The-Earth) ➔ Crust. It is the thinnest layer of the Earth and is the layer we live on. It is made up of a variety of rocks and can reach up to 70km thick in places. The crust ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 7 of 9  itself is divided into large chunks called tectonic plates. There are around 7 large and 12 small plates, which ‘float’ on top of the mantle beneath them. ➔ Mantle. It is the thickest layer of the Earth at 2,900km thick. It makes up nearly 80% of the volume of the Earth. The mantle itself is divided into two layers, the upper and lower mantles, and the heat within these layers drives convection currents. ➔ Outer Core. It is made of liquid iron and nickel and is between 3,500-4,000°C. As the liquid metal swirls around, it induces a current that generates the Earth’s magnetic field. The heat from the core powers the convection currents in the mantle. It is 2,900km thick. ➔ Inner Core. It is the hottest part of the Earth, reaching temperatures between 4,000-4,700°C, which are as hot as the surface of the sun. It is made of solid iron and nickel that are under so much pressure they cannot melt. It is 1,200km thick, and heavy radioactive elements within the core generate the intense heat as they decay. d. Biosphere Bio is a Greek root that means life. The biosphere is comprised of all living things. It includes all microbes, plants, and animals. It extends to the upper areas of the atmosphere where insects and birds can be found. It also reaches the deep parts of the oceans where marine organisms can still survive. (image Source: Which spaces of the earth are part of the biosphere? | Socratic. (n.d.). Socratic.Org. https://socratic.org/questions/which-spaces-of-the-earth-are-part-of-the-biosphere) ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 8 of 9  Organisms interact with the other spheres to survive. Many organisms need oxygen and carbon dioxide from the atmosphere to carry out life processes. Water, which comprises the hydrosphere, is also important to organisms. Finally, the rocks, soil, and minerals that constitute the geosphere also support life. Matter and energy move and cycle between the four different subsystems. These cycles make life on Earth possible. An example of these cycles is the water cycle. Water moves between the different spheres. It absorbs, releases, and transports energy around the world in its different forms. For example, what if water vapor does not fall back to the Earth as rain? Then the bodies of water will be drained, and no life on Earth will exist. Some of the components in the subsystems overlap. The most common example is the soil which can be considered a part of the hydrosphere, geosphere, and even biosphere. Since the soil is a complex material made up of air, soil particles, water, and organisms, it underscores that a clear division among subsystems cannot be drawn. References: Earth's Atmosphere: A Multi-layered Cake. (2019, October 16). Climate Change: Vital Signs of the Planet. https://climate.nasa.gov/news/2919/earths-atmosphere-a-multi-layered-cake/#: Greshko, M. (2021, May 3). Planet Earth, explained. Science. https://www.nationalgeographic.com/science/article/earth In Depth | Earth –. (n.d.). NASA Solar System Exploration. https://solarsystem.nasa.gov/planets/earth/in-depth/ LR Portal. (n.d.). Deped LR Portal. https://lrmds.deped.gov.ph/list/subjects/617 Mann, A. (2022, May 9). Earth: Facts about the Blue Planet. Livescience.Com. https://www.livescience.com/earth.html Moskowitz, C., & Bartels, M. (2021, December 17). What makes Earth unique? Space.Com. https://www.space.com/5595-earth-special-compared-planets.html National Geographic Society. (n.d.). Earth Structure. (C) National Geographic Society. https://www.nationalgeographic.org/topics/resource-library-earth-structure/?q=&page=1&pe r_page=25 Six Things That Make Life on Earth Possible. (n.d.). National Geographic. https://www.nationalgeographic.com/magazine/graphics/one-strange-rock-interactive-earth- solar-system-milky-way-galaxy ______________________________________________________________________________________________ This document contains proprietary and confidential information. Reproduction, redistribution, or forwarding to any third party, in whole or in part, is strictly prohibited unless made with prior written consent from APEC Schools. Violation or noncompliance shall be dealt with according to law. Page 9 of 9