ES_LECTURE_L1-2.pdf

Lesson 1: Characteristics of the Earth that are Necessary to Support Life Most Essential Learning Competency: Describe the characteristics of the Earth that are...

Lesson 1: Characteristics of the Earth that are Necessary to Support Life Most Essential Learning Competency: Describe the characteristics of the Earth that are necessary to support life Lesson Objectives: 1. Identify the different factors necessary to support life in a planet; 2. Describe the characteristics of the Earth necessary to support life; and 3. Explain how each characteristic affect life on Earth. CHARACTERISTICS OF THE EARTH NECESSARY TO SUPPORT LIFE Earth exists for 4.543 billion years. In its early formation life is not possible because the environment does not permit it. However, as time goes by life flourish from minute microorganism into a more complex organism. The presence of life on Earth was made possible due to the following factors: 1. Temperature. It influences how quickly atoms, molecules or organisms move. Low temperature slows down chemical reaction and produces ice that makes liquid water unavailable. High temperature can cause break down of important biological molecules. In Earth’s condition, temperature is just right to support life. 2. Water. It is one of the important ingredients on the different biological processes. Absence of this will interfere reactions necessary for life. However, solid form of this will also hinder living organisms to use it. Water in earth has different forms. It is solid (ice) in the 2 poles and liquid along the equator which allows living organisms to consume it. 3. Atmosphere. It provides significant insulation or shielding from the sun and impact of small to medium size meteorites. Greenhouse gases like carbon dioxide (CO 2) and methane (CH4) traps heat and avoid our planet from freezing. Moreover, ozone (O 3) layer shields the Earth’s surface from harmful UV radiation. Atmosphere also provides chemicals needed for life, such as nitrogen and carbon dioxide. Size of the planet and its distance from the sun affects its ability to hold significant amount of atmosphere. Earth has a right size and distance from the sun that permits it to have a right amount of atmosphere. The presence of gravity also helps in sustaining its atmosphere. 4. Energy. Earth has available energy- rich sunlight to support life. Living organisms like plants and photosynthetic bacteria use light as the source of their energy. Some chemosynthetic organisms rely on chemical energy to support various biological processes. Earth is at right position from the sun that enables it to harness enough amount of sunlight. 5. Nutrients. It is an essential factor used to build and maintain organism’s body structure. Insufficient or absence of nutrients can impede synthesis of the different biological molecules. In Earth, there are processes that recycle nutrients. Water, carbon and oxygen, phosphate and nitrogen cycles are some of the examples. Volcanism also helps in cycling the nutrients. 6. Magnetic Field. The magnetic field deflects sun’s radiation and other charged particles emitted by the sun that may destroy Earth. 1|EARTH S CIENCE 2|EARTH S CIENCE  Lesson 2: Subsystems of the Earth Most Essential Learning Competency: Explain that the Earth consists of four subsystems, across whose boundaries matter and energy flow Lesson Objectives: 1. Identify the four subsystems of the earth; 2. Distinguish the characteristics of each subsystem; 3. Explain how matter and energy flow in the subsystems; 4. Trace the flow of matter and energy in the subsystems. Earth’s Subsystems and the Flow of Matter and Energy Earth is a complex system of interrelating physical, chemical, and biological processes. It is a system in which sets of interconnected components are interacting to form a unified whole. Earth is comprised of four major smaller systems known as subsystems. These are also called as spheres of the Earth. These are the atmosphere, geosphere, hydrosphere, and biosphere. Atmosphere serves as the Earth’s blanket. Its name rooted from the Greek word atmos which means gas and sphaira which means globe or ball. It is composed of gases in varying amount and its relative abundance is also crucial in different parts of the earth. The air in the atmosphere is generally composed of 78% nitrogen, 21% oxygen, 0.9% argon and the remaining 0.10% is made up of different trace gases and vapor. It serves as the Earth’s protection form harmful UV rays and keeps the planet warm through greenhouse gasses. Atmosphere is affected by the Earth’s gravity, so this is the reason why as the altitude increases the amount of gases in the atmosphere decreases. It is composed of layers namely: troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Troposphere layer of the atmosphere where we live lowest part of the atmosphere has all the weather changes and storms source of air we breathe Stratosphere air is dry and thin storms are absent contains an ozone layer important in the absorption of ultra-violet rays Mesosphere reflects radio waves to the curved surface of the earth part of the atmosphere where meteoroids are found Ionosphere contains several layers of electrically charged or ionized gases reflects and modifies radio waves used for communication and navigation. Thermosphere in the lower part, oxygen absorbs the sun’s ultraviolet rays and releases heat different layers of the ionosphere are found here Exosphere layer of the atmosphere beyond the ionosphere has the elements hydrogen and helium Helps atoms to escape back to the atmosphere 3|EARTH S CIENCE  Geosphere comes from the Greek word geos meaning ground. It pertains to the solid part of the earth. It is divided in to three layers such as the crust, mantle, and the core. It is composed of naturally occurring solid aggregate of minerals, organic material or natural glass called rocks. It is also composed of loose particles of rocks that enveloped the surface of Earth called regolith. It contains all the soil, rocks, and minerals present in the crust to the core of the Earth. It comprises the geologic landforms such as mountains and hills. Hydro is a Greek word which means water. Hydrosphere is composed of all the water on Earth in any form. This includes ice, water vapor and liquid water. The permanently frozen part of this subsystem is called cryosphere. Earth is the only planet in the solar system that are known to contain water in all three phases. Water on Earth is constantly and consistently moving because of temperature and salinity. It also plays an important role in absorption and redistribution of solar radiation. Biosphere came from the Greek word bios meaning life. It is composed of all living things and the areas where they are found. It includes all animals, microbes, and plants. It extends to the upper areas of the atmosphere where insects and birds can be found. It also extends to the deep parts of the oceans where marine organisms can still survive. It is also in this zone that the interaction between the different subsystems is most dynamic. In biosphere, each organism plays an important role to the food web. If one is lost the others will be affected. Matter and energy interact and cycle between the four subsystems to sustain and make life on Earth possible. The geosphere is where the rocky part of the earth is in contact with water, air, and life. It is also generally where the spheres intersect and affect each other. The processes that move matter and energy from one sphere to another is called as sphere interactions. Changes in any sphere greatly affect the other spheres as well since all the spheres are interconnected system. The Earth System A system can be described by the way that matter and energy are transferred within the system or to and from other systems. All systems have boundaries, and many systems have matter and energy that flow through them. Even though each system can be described separately, all systems are linked. A large and complex system, such as the Earth system, operates as a result of the combination of smaller, interrelated systems. The operation of the Earth system is a result of interaction between the two most basic components of the universe: matter and energy. Matter is anything that has mass and takes up space. Energy is defined as the ability to do work. Energy can be transferred in a variety of forms, including heat, light, vibrations, or electromagnetic waves. Closed system is a system in which energy, but not matter is exchanged with the surroundings. Open system is a system in which both energy and matter are exchanged with the surroundings. Technically, all systems that make up the Earth system are open. However, the Earth system is a closed system because matter exchange is limited. Energy enters the system in the form of sunlight and is released into space as heat. Only a small amount of dust and rock from space enters the system, and only a fraction of the hydrogen atoms in the atmosphere escape into space. 4|EARTH S CIENCE  The four subsystems are closely linked through the biogeochemical cycles which involves biological, geochemical, and chemical factors. These cycles are alleyways by which substances move through biotic which is the biosphere and abiotic which is the geosphere, atmosphere and hydrosphere, components of Earth. It allows the circulation of important nutrients that form and support life like carbon, oxygen, nitrogen, phosphorus, calcium, and water. It also maintains the balance of substances in the different subsystem of the Earth. Any interference and disturbances in the flow of matter and energy may cause damage to any of the subsystems and its components. The Earth system. (Source: https://www.earthonlinemedia.com) The arrows in the diagram indicate the interaction among the components. Earth system is essentially a closed system. It receives energy from the sun and returns some of this energy to space. A closed system is a system in which there is only an exchange of heat or energy and no exchange of matter. Energy enters the biosphere as sunlight. Plants change this energy into chemical energy through the process of photosynthesis. Then, the energy is passed to organisms that eat the plants. Energy and matter is also passed between organisms when they eat one another. The transfer of energy and matter does not stop when a living thing dies. Dead organisms are consumed by decomposers, such as bacteria and fungi. The decomposers break down the remains into simple materials. These materials, such as carbon dioxide, are used by plants to make food during photosynthesis. Energy in the biosphere is transferred from the sun to plants and then from one organism to another (Abon, 2016). These components are also systems in their own right and they are tightly interconnected. The main components of the earth system are interconnected by flows (also known as pathways or fluxes) of energy and materials. The most important flows in the earth system are those concerned with the transfer of energy and the cycling of key materials in biogeochemical cycles 5|EARTH S CIENCE  How do spheres interact? Balancing the Earth’s Energy Budget What is the source of Earth’s energy? Almost all of Earth’s energy comes from the sun. A tiny fraction of Earth’s energy comes from ocean tides and geothermal sources such as lava and magma. Energy is transferred between Earth’s spheres, but it is not created or destroyed. Any addition of energy to one sphere must be balanced by an equal subtraction of energy from another sphere. The movement of energy through Earth’s system forms an energy budget. 6|EARTH S CIENCE