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BLOCK # 2
Do you remember what we learned about the process of forest formation? Well thanks to this, we have plenty of forest en Ecuador, however, these forests depend on the soil to obtain the water and minerals they need to grow and develop and in the same way, the soil depends on the vegetation.
SOIL COMPOSITION
The formation of the soil begins in the moment when the rock is exposed to the environmental conditions. Usually, this process takes a lot of time, maybe thousands of years, because of the hard weather, topography and rocks structure. The rupture of the rocks happens because of the changes between the day and night. This process starts with the physical and chemical rupture of the rocks, named
weathering. The first living things that habit a territory, the lichens, will deposit organic material in the soil. This material will be decomposed by a group of living things called decomposers. 2
SOIL COMPOSITION The soil is considered as a superficial layer of the earth crust. The depth of the soil goes from a few centimeters to 2 meters. The top layer (O) has organic material, and it’s usually found in the forests. The layer (A) has organic material is mixed with the minerals from the soil. Usually it’s darker than O. This layer is fertile.
The layer B has some minerals mixed with water and some clay particles
The deepest layer (C) has inorganic material
Inorganic minerals in the soil On the ground we can find different minerals. They depend on the composition of the rock that originated the soil and its interaction with living things.
INORGANIC MINERALS IN THE SOIL Resulting Minerals
Former Minerals
Quartz
Clay
Feldspar
Carbonates
Sulphate
Organic minerals in the soil The result of the decomposition of the waste produced by living organisms in the forest makes up what is known as Humus. The worms, insects and other organisms are responsible of producing the humus, which consists of organic substances such as sugars, proteins and others.
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SOIL PROPERTIES The soil of each ecosystem has different physical and chemical properties.
PROPERTIES
PHYSICAL
COLOR
POROSITY
WATER RETENTION
CHEMICAL
PERMEABILITY
HEAT
ACIDITY
FERTILITY
Investigate. Complete the chart: COLOR POROSITY WATER RETENTION PERMEABILITY HEAT ACIDITY FERTILITY ACTIVITIES: 1. Why is soil necessary for the environment? 2. What is weathering? 3. What is the job of the decomposers? 4. Draw and label the layers of the soil. Mention the characteristics of each one. 5. Mention the inorganic minerals of the soil. 6. What is humus? 7. Complete the chart. PROPERTIES OF THE SOIL PHYSICAL CHEMICAL
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Materials:
3 samples of the different types of soil (in plastic bags) 3 sheets of napkins A magnifying glass Some water A spoon 3 small cups (resistant to heat) An oven 3 funnels 3 jars A test tube A chronometer
Procedures: -
Place some of the soil on a sheet of napkin. Repeat this step with the other 2 samples. Take a look of the characteristics of each type of soil: color, texture, etc. Use the lens. Remember to label each sample according to the kind of soil. Pour some water on your hands and mix each sample. Make a ball with this mixture (not too big) Press you finger on the ball and check the characteristics.
CONCLUSION Write the consistency of each soil. -
The sandy soil is …………………………………………………
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The clay soil is …………………………………………………
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The slimy soil is ………………………………………..………..
Part 2 -
Add 2 spoons of each of the mixtures in the 3 glasses. Heat them in the oven for 5 minutes Have the 3 funnels ready with the napkins, on the jars. Pour the mixture in each funnel and add 30 ml of water. Make a registration chart to compare the time that passes since the first drop of water falls until all the water has been filtered.
Share your results and tell what you have learned!!
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Soil erosion is a term for soil that is taken away from the land, or very suddenly being washed away or blown away. Water and wind naturally remove soil from the land, but usually at a rate which is the same as soil is formed, so some soil is taken away but this is replaced. When soil erosion is sudden, it has a negative impact on the land. Sudden erosion is caused by extreme rainfall literally washing soil away, rivers overflowing and taking soil with them to the sea or by tsunamis, tornadoes etc. When this happens, the land is less productive, so crops do not grow as well. Soil contains many nutrients which are beneficial to crops, so the land cannot immediately recover after erosion has occurred. There are fears that soil erosion will become much more widespread as a result of extremes of weather caused by global warming. It becomes a problem when human activity causes it to occur much faster than under natural conditions.
CAUSES OF SOIL EROSION Wind and water are the main agents of soil erosion. The amount of soil they can carry away is influenced by two related factors: * speed - the faster either moves, the more soil it can erode; * Plant cover - plants protect the soil and in their absence wind and water can do much more damage.
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THE IMPORTANCE OF PLANTS: Plants provide protective cover on the land and prevent soil erosion for the following reasons: * Plants slow down water as it flows over the land (runoff) and this allows much of the rain to soak into the ground; * Plant roots hold the soil in position and prevent it from being washed away; * Plants break the impact of a raindrop before it hits the soil, thus reducing its ability to erode; * Plants in wetlands and on the banks of rivers are of particular importance as they slow down the flow of the water and their roots bind the soil, thus preventing erosion.
ACTIVITIES 1. Define the word: SOIL EROSION 2. Mention some factors that contribute to soil erosion. 3. What can we do to prevent soil erosion? 4. Why do plants help the environment? 5. Suggest some ideas to prevent the erosion of the soil in the place where you live. 6. What can happen if the soil erosion becomes faster?
DEBATE Should we use the soil for agriculture and development of living things or should we take care of the forests and look for another option to find food and medicines? Make groups and share your opinions. Then expose your ideas with good and bad points of view. 7
What is deposition by Water? 1. Erosion and Deposition Erosion and deposition change the Earth´s surface. Erosion is the process through which sediment and other material are removed. Deposition is the process through which sediment and other material are deposited, or laid down, or dropped in a new place. These processes have been happening throughout Earth´s history. There are several agents that cause erosion and deposition Agents of erosion and deposition include water, gravity, wind, and ice. As these agents interact with Earth´s surface, they wear it away, move it, and deposit it elsewhere changing its shape.
2. Erosion and deposition by Streams The following conditions produce faster erosion: Faster flow Steeper slopes Greater discharge of water These conditions produce faster deposition: Slowing streams Conditions that have caused higher rates of erosion
3. Formation of Landforms by Streams Some landforms result from stream erosion. Streams erode soil and rock to form channels. Over many years, the erosion of sediment from the bottoms of channels may cause canyons and valleys to form. This is more likely to happen in locations where rock is softer and easily eroded.
4. Erosion and Deposition by Groundwater, Waves, and Currents Groundwater erosion can change the land. Groundwater can erode rock, forming underground caverns or spaces. The roof of a cavern may fail, producing a sinkhole. Waves and currents can cause shoreline changes and land formations. Wave action against coastal rock causes many formations – sea cliffs, sea caves. Beaches, sandbars, and barrier islands are formed and destroyed by erosion and deposition by waves and currents.
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Practice.A. Complete the graphic with the correct information
Erosion and Deposition Erosion
Deposition
___________________ ___________________ ___________________ ___________________ ___________________
___________________ ___________________ ___________________ ___________________ ___________________
Agents that cause erosion and deposition such as: ___________________ ___________________ ___________________ ___________________ ___________________ ___________________ ___________________
B. Critical Thinking 1. You have a rock in your hand. It is very hard. If you compare and contrast water with that rock, which one would u think is stronger in a long period of time. Explain your answer. ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ C. Venn Diagram. Complete the following diagram comparing and contrasting Erosion and Deposition.
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Natural Resources Fusion Unit 4, Lesson 1 What are Earth´s Natural Resources?
1. Natural Resources Natural Resources improve life. A natural resource is any natural material that is used by people to help them survive and improve their lives. Natural resources can come from the Earth´s atmosphere, crust, freshwater, oceans, and living things. Some natural resources are air, soil, freshwater, oil, rocks, minerals, plants, forests, crops, and wildlife.
2. Renewable and Nonrenewable Resources Natural Resources are renewable or nonrenewable Renewable resources are those that can be replaced at the same (or nearly the same) rate at which the resource is used. For example, water is continuously replaced through the water cycle. Trees are considered a renewable resource because cut trees can be replaced planting new trees. Some renewable resources are considered inexhaustible because they cannot be used up. Solar and wind energy are considered inexhaustibly resources. A nonrenewable resource is a natural resource that forms much more slowly than it is used. These resources may take thousands or millions of years to form. Coal, oil, copper, and aluminium are nonrenewable resources. The sustainability of a resource is a function of how quickly the resource is replaced versus how quickly it is consumed. For example, forests are renewable resources because trees can be replaced, but the rate of harvest has a great impact on the sustainability of the resource. The same is true for groundwater and wildlife.
3. Material and Energy Resources Natural resources are used in many ways Natural resources can be categorized as material resources and energy resources according to how they are used. As with all natural resources, material and energy resources also are classified as renewable and nonrenewable. A material resource can be used as food or drink, or to make objects. For example, iron is used to make steel. Wheat is harvested and processed into food. Energy is the ability to do work. An energy resource is any natural resource that humans use to convert energy into a usable form. Energy 10
cannot be created, but it can be converted from one form to another. For example, when coal is burned, the chemical energy in the coal is converted to heat. Energy can also be transferred from one object to another, such as when heat moves from warmer to cooler substances by convection, conduction, or radiation. Trees are a material resource when they are used to make products, such as this guitar
Cedar tree
Practice.A. Fill the following Venn Diagram comparing and contrasting Renewable and Nonrenewable Resources.
B. Critical Thinking.1. If freshwater is a renewable resource, why do we have to be careful with it? ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ 11
Human Impact on Land Fusion Unit 4, Lesson 2 What impact can human activities have on land resources and soil quality?
1. How humans use Land Humans use land in five major ways: for residential use, agricultural use, commercial/industrial use, transportation, and recreational use. Agricultural use occurs mostly in rural areas, which contain few people and have large areas of open space. Rural areas or natural (wild) areas that have been altered very little by people are most likely to be sites for recreation. Urban land is largely covered for the most part by buildings and roads. As cities and towns grow, rural and natural areas are changed, or urbanized. Urban sprawl occurs when natural or rural areas that lie near cities or towns are developed to create roads or housing in response to the expansion of the human population in the urban area. Urbanization is one of the main causes of land degradation.
2. Land Degradation Land degradation is the process by which human activity and natural processes damage land to the point that it can no longer support the local ecosystem. In addition to urbanization, deforestation and poor farming methods can cause degradation. Deforestation is the removal of trees and other plants, which leads to accelerated soil erosion. Surface mining techniques, in which vegetation is removed from the land, may have similar effects. Poor farming methods also leave the soil vulnerable to erosion and land degradation. When cattle or other livestock are kept in one area for too long, they can eat too much vegetation, or overgraze area; as plants and their roots are removed from the soil, erosion increases. Another poor practice involves planting the same crops in the same place year after year, which causes some soil nutrients to be used up. Crop rotation can relieve this pressure on the soil. When cities expand, natural vegetation is removed and land areas are paved; both these actions change the rate of erosion and deposition and reduce the amount of available farmland. All of these factors can lead to the desertification of an area. Desertification is the process by which land becomes more desertlike and unable to support living systems. 12