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OUTCOMES By the end of this topic you should be able to:  Describe the interacting subsystems of Earth that together produce a unique biome  Explain.

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Presentation on theme: "OUTCOMES By the end of this topic you should be able to:  Describe the interacting subsystems of Earth that together produce a unique biome  Explain."— Presentation transcript:

1 OUTCOMES By the end of this topic you should be able to:  Describe the interacting subsystems of Earth that together produce a unique biome  Explain why water is an essential ingredient in the maintenance of the Australian environment  Describe how water plays an important part in weathering and the subsequent production of soils  Outline water resources, past and present Water Issues

2 Topic Overview There are 5 parts to this topic 1. Spheres of the Earth 2. The importance of water as a solvent in Biological Systems 3. The hydrologic cycle 4. Australia’s Aquatic Past

3 Spheres of the Earth Part 1-Lesson 1

4 Introduction Three quarters of Earth is covered by water. This liquid water which we have so much of is what makes us unique from different planets. It’s very rare in our solar system.

5 Introduction Water is one of the key reasons why Earth is able to sustain life. Water is often what scientists are looking for on other planets in the search for other forms of life in our solar system.

6 Introduction The rocks that form the skeleton of our planet have been slowly eroded away by the actions of water over time. This has resulted in soils in which we depend upon to grow food.

7 Introduction Of the abundant water on Earth, very little of it is fresh. The distribution of this fresh water is what determines types of habitats. All Australian environments reflect the quality and amount of water they receive each year.

8 Introduction Human activities have altered the quality and distribution of water in this country and countries around the world. Governments are now struggling to protect this resource which is one of our most important. In this section we will look at water on our planet and why it’s so important.

9 Spheres of the Earth Scientists refer to the Earth in different spheres. These spheres are a zone in which a particular feature is found. Atmosphere Lithosphere Hydrosphere Biosphere

10 Atmosphere This is the zone of gases that extend from the surface upwards until outerspace. There is a gradual thinning of gasses and no clear boundary between the atmosphere and space.

11 Atmosphere Air particles have been detected at heights of 1000km. The space shuttle orbits the Earth at about 300km! According to NASA, they define space at an altitude of 85km. About 80% of the atmosphere’s mass is in the bottom 12 kilometres.

12 Lithosphere This is the zone of rigid rock that extends from the surface down to the mantle where the rock becomes partially molten. The depth of the lithosphere varies from 5-100 kilometres. It’s average is around 70km.

13 Hydrosphere This is the zone of water which extends from within the lithosphere and possibly mantle to about 12 kilometres into the atmosphere. Water in the hydrosphere can occur as ice, vapour and liquid.

14 Biosphere This is the zone of which life can be found. The biosphere can be has high as 12km above ground and deep within the Earth. The depth is uncertain however scientists have estimated this to be between 5-10km.

15 Natural Events That Impact on These Spheres We are very familiar with the effects of floods, fire and drought in Australia. These events can affect the atmosphere, lithosphere, hydrosphere and biosphere in a number of ways.

16 Natural Events That Impact on These Spheres Other less common events which impact on these spheres include volcanic eruptions, earthquakes, ice ages and meteorite collisions. See the table on page 85 Prelim Spotlight Text to examine some natural events and their frequency.

17 Review Three quarters of Earth is covered by water. This liquid water which we have so much of is what makes us unique from different planets. It’s very rare in our solar system. Scientists refer to the Earth in different spheres. These spheres are a zone in which a particular feature is found. Atmosphere Lithosphere Hydrosphere Biosphere Natural events can affect the atmosphere, lithosphere, hydrosphere and biosphere in a number of ways.

18 Homework Read pages 82-85 Prelim Spotlight Text Start new electronic vocabulary list for this module

19 Spheres of the Earth Part 1-Lesson 2

20 Review Three quarters of Earth is covered by water. This liquid water which we have so much of is what makes us unique from different planets. It’s very rare in our solar system. Scientists refer to the Earth in different spheres. These spheres are a zone in which a particular feature is found. Atmosphere Lithosphere Hydrosphere Biosphere Natural events can affect the atmosphere, lithosphere, hydrosphere and biosphere in a number of ways.

21 Global Water Budget The GWB refers to the total distribution of water in all its forms and reservoirs on Earth. This distribution is uneven due to the following reasons: Topography Latitude Climate

22 Topography This refers to the slope of the Earth’s surface. Since the Earth’s surface is uneven, water naturally accumulates in areas with the lowest elevation. If the Earth was perfectly smooth and spherical, the entire planet would be by water 1km deep!

23 Topography Mountains can also have a great effect on where rain falls. When moist air is pushed upwards as it travels over mountains it will condense and rain on one side of the mountain. As the air moves over the mountain and down the opposite side, the air sinks and warms resulting in dry air on the other side of the mountain. This is called fohn wind. How do you think this affects environments?

24 Topography Australia’s Great Dividing Range has this effect which is partly why areas to the East of the range tend to be much wetter than those to the west.

25 Latitude Many of the worlds deserts are located on or near the Tropics of Cancer and Capricorn and areas along the equator receive some of the highest rainfall. This is because of the convection of air in the atmosphere.

26 Latitude The air along the equator is hot all year and rises by convection. As the air rises it cools, creates clouds and high levels of rainfall. This air is then moved north or south and sinks as it cools. As it sinks, it’s warmed again and because its dry air clouds do not form. This is the reason why most deserts occur near the tropics.

27 Climate Climate is an areas long term weather patterns and determines how much precipitation an area receives. Climate is influenced by latitude, topography, altitude, wind directions, ocean currents and proximity to oceans.

28 Interrelationships Earth’s systems are very complex and interconnected. A change to one system can impact others. For example, ocean currents are the main factor in the redistribution of heat around the world. This is called the great ocean conveyor belt.

29 Interrelationships Disruptions to this cycle could prevent the transfer of heat to higher latitudes. This would drop temperatures and build up ice around the poles. As a result sea levels would drop, and salinity of ocean water would increase. This would have a dramatic effect on coastlines. See Figure 3.10 page 88 Prelim Spotlight Text

30 Interrelationships Changes in one system can act as a trigger for changes in others. These can be positive or negative. Positive feedback amplifies a change to a system and cause it to increase in a snowball effect. Negative feedback cancels out changes in a system and promotes stable conditions. Read the scenario’s on page 89 Prelim Spotlight Text

31 Activity Complete Activity 3.2 Prelim Spotlight Text page 89 together.

32 Review The GWB refers to the total distribution of water in all its forms and reservoirs on Earth. This distribution is uneven due to the following reasons: Topography Latitude Climate Earth’s systems are very complex and interconnected. A change to one system can impact others. Positive feedback amplifies a change to a system and cause it to increase in a snowball effect. Negative feedback cancels out changes in a system and promotes stable conditions.

33 Homework Read pages 86-89 Prelim Spotlight Text Update electronic vocabulary Complete ‘To Think About’ page 89 Prelim Spotlight Text Complete DOT Points 1.1-1,3


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