Lesson 1-Character of Earth that supports life and the Earth's Subsystems.pdf

What is Earth? Planet Earth is the 3rd planet from the sun. We live in a unique planet which may be the only one in our solar system that has life in it. What do you think? Are we alone? What are the characteristics that enable Earth to support life? JONNA FE MARIE T. SUMINGUIT Habitable Planets...

What is Earth? Planet Earth is the 3rd planet from the sun. We live in a unique planet which may be the only one in our solar system that has life in it. What do you think? Are we alone? What are the characteristics that enable Earth to support life? JONNA FE MARIE T. SUMINGUIT Habitable Planets A habitable planet has abiotic factors and characteristics that are just right for allowing life to exist. Life is limited to a temperature range of -15oC to 115oC. Because of its distance from the sun, Earth has a temperature of 0oC to 100oC which allows life to exist. The length of the day and night also contributes to temperature that can sustain life. There are a number of factors that enable life to exist on Earth: 1 Presence of Liquid Water Organisms mostly need water. Nutrients need to be dissolved in water to be used. Most chemical activities occur in water. 2 Atmosphere The presence of an atmosphere makes Earth livable. If Earth had no atmosphere, it would not have maintained the temperature and gases necessary for our survival and sustenance. Earth has the right density to keep its atmosphere. If it had lesser density, the atmosphere would have escaped. 3 Sun All energy comes from the sun. Animals use oxygen to carry out the process of respiration to make energy. Plants use carbon dioxide to carry out the process of photosynthesis to make energy from sunlight. Do plants need oxygen to make energy? Why or why not? Earth's Subsystems Everything in the Earth can be placed into one of four major subsystems: land, water, living things, or air. Earth as a system is composed of numerous interacting parts or subsystems. These four subsystems are called "spheres." Specifically, they are the "lithosphere" (land), "hydrosphere" (water), "biosphere" (living things), and "atmosphere" (air). The Lithosphere The lithosphere is the rigid, rocky outer layer of the Earth, consisting of the crust and the solid outermost layer of the upper mantle. It extends to a depth of about 60 miles (100 km). It is broken into about a dozen separate, rigid blocks or plates. The Hydrosphere The hydrosphere is the total amount of water in a planet. The hydrosphere includes water that is on the surface of the planet, underground, and in the air. A planet’s hydrosphere can be liquid, vapor, or ice. On Earth, liquid water exists on the surface in the form of oceans, lakes, and rivers. It also exists below the ground- as groundwater, in well and aquifers. Water vapor is most visible as clouds and fog. The frozen part of Earth's hydrosphere is made of ice: glaciers, ice caps and icebergs. The frozen part of the hydrosphere has its own name, the cryosphere. The Water Cycle Water moves through the hydrosphere in a cycle. Water collects in clouds then falls to Earth in the form of rain or snow. This water collects in rivers, lakes, and oceans then it evaporates into the atmosphere to start the cycle all over again. The Biosphere It contains all the planet's living things. This sphere includes all the microorganisms, plants, and animals of Earth. Within the biosphere, living things form ecological communities based on the physical surroundings of an area. These communities are referred to as biomes. Deserts, grasslands, and tropical rainforests are three of the many types of biomes that exist within the biosphere. The Atmosphere It is a very shallow layer. One half lies below an altitude of 5.6km, 90% occurs within 16km of the Earth’s surface. This thin blanket of air provides us with air that we breathe. It also protects us from the sun’s dangerous ultraviolet radiation. The energy exchanges that continually occur between the atmosphere and Earth’s surface and between the atmosphere and space produce our weather and climate. Earth's Subsystems: A Summary Subsystem Description Lithosphere Rigid, rocky outer layer of the Earth, consisting of the crust and the solid outermost layer of the upper mantle. Hydrosphere The total amount of water in a planet, including water on the surface, underground, and in the air. Biosphere Contains all the planet's living things, including microorganisms, plants, and animals. Atmosphere A thin blanket of air that provides us with air to breathe and protects us from the sun's dangerous ultraviolet radiation. Earth: A Complex System Each of these four spheres can be further divided into sub-spheres. The interactions between these subsystems create a complex and dynamic system that supports life on Earth.