UNIT 2, Atmosphere.pptx,c ourese half scholaree of hte jfgj

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1. UNIT 2. STRUCTURE OF THE EARTH Objectives Discuss Outer layers like: Atmosphere Hydrosphere Biosphere Describe all inner layers like inner core, outer core, sial, sima and mantle. Analyze components of all layers of earth.

2. 2.1.External Earth Layers The outer layers are: Atmosphere Hydrosphere Biosphere

3. 2.1.1. Atmosphere The atmosphere is the envelope of gases surrounding the earth. It contains the gases that support all forms of life on earth. This envelope of air is dense at the sea level. It thins out with increase in altitude. Atmosphere is the layer of gases surrounding the earth. It is composed different gases. It is about 360 km thickness.

4. Composition of Atmosphere Atmosphere composes: Gases exist as mixtures. Nitrogen (78%) Oxygen (21%) Other gases (1%), Argon, Carbon dioxide, Helium, Methane etc. Dust particles. These are dust particles from the ground. Smoke particles Ash Particles Water Vopour ( Moistures)

5. Cont..

6. The structure of the atmosphere The atmosphere is a mixture of various gases surrounding the earth. It provides all gases that are essential for sustaining all life forms on the earth. Based on temperature variation, the atmosphere is made up of four layers: the troposphere, the stratosphere, the mesosphere and the thermosphere.

7. Layers of Atmosphere Troposphere . This is the lowest layer of atmosphere. It is up to 15 km depth. It comprises majority of water Vopour in the atmosphere. It is where all dust particles, ash and smokes are concentrated.

8. Cont... Atmosphere

9. Cont.. Climatically, the troposphere is the most important because all the elements of weather and weather phenomena occur in this layer (e.g. evaporation, condensation, and precipitation of different forms like fog, cloud, dew, frost, rainfall, snowfall, thunder, lightning, atmosphere storms, etc.). This layer contains about 75% of gaseous mass of the atmosphere, most of water vapour , aerosols and pollutants.

10. Cont... It is characterized by the following: It is the lowest layer of the atmosphere. The upper limit of the troposphere is called the tropopause. The temperature decreases with altitude at the rate of 6.5°C per km or 3.6°F/1000ft. The atmospheric pressure decreases also with altitude and reaches to 100 millibars and 250 millibars over the equator and poles respectively at tropopause. It lies 15km above the sea level.

11. Cont.. All weather phenomena occur in this layer. These are evaporation, condensation and precipitation. Condensation is the conversion of Vopour or gas into a liquid of different forms. Precipitation is water that falls to the ground as rainfall, snow or hail. The height of tropopause is 17 km over Equator and 9 to 10 km over the poles.

12. Stratosphere : The stratosphere is the layer which is extending from 16 to 50 km above the sea level. It is characterized by the following: There is increase of temperature due to absorption of ultraviolet solar radiation by ozone layer and lesser density of air. There is nearly absence of weather phenomena because of dry air and rare occurrence of clouds.

13. Cont.. The lower portion of the stratosphere having maximum concentration of ozone is called ozonosphere, which is confined between the heights of 15 to 35 km from sea level. Depletion of ozone would result in the rise of temperature of the ground surface and lower atmosphere. The main causes of ozone destruction are halogenated gases called chlorofluorocarbons (CFCs: chlorine, fluorine and carbon). This results to global warming, acid rain, melting of continental glaciers and rise in sea level, skin cancer, poisonous smoke, decrease in photosynthesis, ecological disaster and ecosystem instability. The upper limit of the stratosphere is known as stratopause .

14. Mesosphere The mesosphere extends between 50 km and 80 km. Temperature decreases as height increases. In fact, the rise of temperature with increasing height in the stratosphere stops at the stratopause. At the uppermost limit of the mesosphere (80 km), the temperature drops at -80° C and may go down as low as - 100° C to -133° Celsius at mesopause. This layer is characterized by very low air pressure ranging between 1.0 millibars at 50 km altitude representing stratopause, and 0.01 millibars at the mesopause (between 90 and 100 km).

15. Thermosphere It extends from 80 km to 360 km. It is composed of Ionosphere and Exosphere. Its second name is The ionosphere . thermosphere is a  layer of Earth's atmosphere  that is directly above the  mesosphere  and below the  exosphere . It extends from about 80 km to between 360-800 km above Earth's surface. It is very hot layer Temperatures rise as the altitude increases because the solar radiation heats upper parts of thermosphere.

16. Cont... The boundary between the thermosphere and the exosphere above it is called the thermopause. At the bottom of the thermosphere is the mesopause, the boundary between the thermosphere and the mesosphere below. Although the thermosphere is considered part of Earth's atmosphere, the air density is so low in this layer that most of the thermosphere is what we normally think of as outer space. In fact, the most common definition says that space begins at an altitude of 100 km (62 miles), slightly above the mesopause at the bottom of the thermosphere.

17. Significances of Atmosphere Earth’s atmosphere is a thin blanket of gases and tiny particles: together called air. We are most aware of air when it moves and creates wind. All living things need some of the gases in air for life support. Without an atmosphere, Earth would likely be just another lifeless rock. Earth’s atmosphere, along with the abundant liquid water at Earth’s surface, are the keys to our planet’s unique place in the solar system. Much of what makes Earth exceptional depends on the atmosphere. Let’s consider some of the reasons we are lucky to have an atmosphere.

18. a) Indispensable for Life of Earth Without the atmosphere, Earth would look a lot more like the Moon. Atmospheric gases, especially carbon dioxide (CO 2 ) and oxygen (O 2 ), are extremely important for living organisms. How does the atmosphere make life possible? How does life alter the atmosphere? In  photosynthesis  plants use CO 2  and create O 2 . Photosynthesis is responsible for nearly all of the oxygen currently found in the atmosphere. By creating oxygen and food, plants have made an environment that is favorable for animals. In respiration, animals use oxygen to convert sugar into food energy they can use. Plants also go through respiration and consume some of the sugars they produce.

19. b) Crucial Part of the Water Cycle As part of the  hydrologic cycle , which was detailed in the Earth’s Fresh Water chapter, water spends a lot of time in the atmosphere, mostly as water vapor. All  weather  takes place in the atmosphere, virtually all of it in the lower atmosphere. Weather describes what the atmosphere is like at a specific time and place, and may include temperature, wind, and precipitation. Weather is the change we experience from day to day. Climate is the long-term average of weather in a particular spot. Although the weather for a particular winter day in Tucson, Arizona, may include snow, the climate of Tucson is generally warm and dry.

20. c) Ozone Layer Makes Life Possible Ozone  is a molecule composed of three oxygen atoms, (O3). Ozone in the upper atmosphere absorbs high-energy  ultraviolet (UV) radiation  coming from the Sun. This protects living things on Earth’s surface from the Sun’s most harmful rays. Without ozone for protection, only the simplest life forms would be able to live on Earth.

21. d) Moderates Earth’s Temperature Along with the oceans, the  atmosphere  keeps Earth’s temperatures within an acceptable range.  Greenhouse gases  trap heat in the atmosphere so they help to moderate global temperatures. Without an atmosphere with greenhouse gases, Earth’s temperatures would be frigid at night and scorching during the day. Important greenhouse gases include carbon dioxide, methane, water vapor, and ozone.

22. 2.1.2. Hydrosphere Hydrosphere is the layer of water that covering the earth. It is the total amount of water on a planet. It covers or occupies about 360 million on the earth's total surface area which is 510 million . Water covers up to 71% on the earth’s surface. It includes water on the surface of the planet, underground, and in the air. This layer is habitat for huge number of living organisms or aquatic life. The salt water occupies on the earth’s surface is estimated to be 97.5% of surface water. Fresh water is only 2.5% which small amount of them can be accessible for human use.  

23. Cont.… It is a layer composed the masses of water bodies like: Oceans including Pacific, Atlantic, Indian, Southern(Ant-arctic), Arctic Oceans. Seas including Mediterranean, Red Sea, Dead sea, Baltic sea, Okhotsk sea etc. Lakes including Lake Superior and Lake victoria. Rivers like River Amazon, River Nile and yellow river.

24. Importance of Hydrosphere The major importance of the hydrosphere is that water sustains various life forms and plays an important role in ecosystems and regulating the atmosphere.  The following are the functions of a hydrosphere. Water is the most important part of living cells Every cell in a living organism is built up of about 75% of water, hence allowing the cell to function appropriately. Cells would not be able to carry out normal functions and life cannot exist without water. b) Human needs Humans use water in many ways. Drinking water is the most obvious use, but it is also used for domestic purposes like washing and cleaning and in industries.

25. Cont.. c) Water provides habitat Hydrosphere provides a place for many plants and animals to live in. Many gasses like CO 2 , O 2 , nutrients like ammonium and nitrite(NO – 2 ) as well as other ions are dissolved in water. The presence of these substances is essential for life to exist in water. d) Regulate Climate The water’s specific heat is its unique characteristic. This indicates that water takes a lot of time to heat up and a lot of time to cool down. It helps in regulating temperatures on earth as they stay in a range that is acceptable for life on earth to exist.

26. Cont. e) Water are solvents which dissolves soluble substances like rock minerals. f) Water is a source of electricity. Water is also utilized in generating electricity through hydropower. g) Irrigation. Water is used for irrigation of agriculture and domestic animals. h) Transportation. Some water bodies like Oceans, Seas, Lakes and even rivers are used for transportation of people and goods from one location to another. i) Minerals. Some water bodies are source of minerals like salts, Crude oil, natural gas, limestone manufactured for cements and others. j) Atmospheric moisture absorbs terrestrial heat and radiates it back to the earth’s surface keeping lower atmosphere warm.

27. 3.1.3. Biosphere Biosphere is the layer of earth where life can exists. This is the zone where all living organisms live together. It consists the lithosphere, lower atmosphere and hydrosphere. The biosphere, which includes the ground and the air, is characterized as the region of the planet where organisms live. The biosphere is defined as the region on, above, and below the Earth’s surface where life exists. The biosphere is a narrow zone on the surface of the earth where soil, water, and air combine to sustain life. Life can only occur in this zone. From fungi and bacteria to large animals, there are several different types of life.

28. Cont.… The biosphere is related to the lithosphere, hydrosphere, and atmosphere, which are all spheres of the physical world. The lithosphere is the Earth’s solid outer layer, which contains rocks, sand, and soil. The biosphere is characterized as an environment that contains all living organisms and the products of their activities. As a result, it plays a vital role in the conservation of ecosystems, i.e., the life of species and their reciprocal interactions. And the biosphere is critical for climate regulation. Any of the main greenhouse gases, such as methane, carbon dioxide, and nitrous oxide, are affected by the biosphere.

29. Cont.. Various environmental conditions, such as favorable temperature and moisture, are needed for organisms to live on Earth. Energy and nutrients are also needed by the species. The biosphere of the Earth contains all of the mineral and animal nutrients needed for life.

30. Components of Biosphere The components of the biosphere are categorized as biotic, abiotic, and energy components. Abiotic components include non-living elements such as the lithosphere, atmosphere, and hydrosphere, while biotic components include plants, animals, and microorganisms.

31. Cont.. Abiotic components of Biosphere I. Lithosphere (Geosphere) It forms the terrestrial portion of the biosphere. It is the stiff, rocky outer layer of the Earth which is made up of the crust (the rocks that make up the continents and the ocean floor) and the upper mantle’s solid outer layer. These layers support life by giving shelter and sustenance from tiny bacteria to big mammals and lofty trees. It also stretches to a depth of almost 60 kilometers, and its lower mantle and core are the only parts that do not support life and are not a part of the biosphere.

32. Cont.. II. Atmosphere It is the region that contains different gases like oxygen, carbon dioxide, and other gases. This gaseous envelope makes it possible to see insects, birds, and other creatures soar high or fly above 2000 meters in the sky. With the increase in height, the concentration of oxygen level goes on decreasing, which limits the availability of organisms in the atmosphere. The region in the atmosphere up to which animals or other forms survive or sustain makes up the biosphere.  Besides providing oxygen for respiration, the ozone layer of the atmosphere plays a crucial role in protecting living forms from the sun’s harmful ultraviolet rays.

33. Conti..  Hydrosphere It forms the aquatic portion of the biosphere as all the water components of the Earth, such as waterways, ponds, oceans, etc., are included in it. However, several solid forms, such as glaciers, are also included under the hydrosphere. It maintains the ecosystem by temperature regulation on Earth and supplying water to all living things. Every component of the hydrosphere is responsible for the existence of living forms .

34. Biotic components of Biosphere Biotic components of Biosphere Plants:  These are autotrophic organisms that manufacture their food themselves through a process called photosynthesis. These are the primary producers, becoming the only primary source for all living organisms. Animals:  These are heterotrophic organisms that depend on primary producers or other animals for their food, release energy and reserve it for future purposes. Thus, they are known as consumers. Microorganisms:  They serve as decomposers that obtain their nutrition through the breakdown of waste or dead and decayed bodies. Fungi, bacteria, algae, viruses, etc., are under this category. 

35. Energy components of Biosphere It is the third and most important part of the biosphere, without which life on this planet would not have been conceivable. All biological forms on this planet depend on it for generation and reproduction. Every living thing functions like a machine that transforms one form of energy into another while also using it to do work. Sun is the ultimate source of energy for all living organisms in the biosphere for existence.

36. Biosphere boundaries and interactions between components The boundaries of the biosphere are not fixed and can vary. The relationships between the atmosphere, lithosphere, hydrosphere, and living organisms are complex and interrelated. For example, the atmosphere plays a crucial role by providing gases and regulating the climate necessary for supporting life. The lithosphere provides physical habitats and vital nutrients for organisms. Similarly, the hydrosphere contributes water and aquatic ecosystems to the biosphere. These components involve nutrient cycling, energy flow, and gas exchange, affecting ecosystems’ distribution and functioning within the biosphere.