G18: Geomorphic Processes, Endogenic & Exogenic Forces, Geomorphic Agents | Class 11 Geography

0:00 Jai Hind. We were talking about the Fundamentals of Physical Geography. Although it has been some time since our last session. Because I got busy in between and the sessions could not be recorded regularly. But from today once again we are resuming our sessions of Fundamentals of Physical Geography. We have already read about four chapters. From today we are starting a new chapter, Chapter Fifth. And chapter fifth is titled Geomorphic Processes. Although this is the latest edition of NCERT. If you look at the older edition of NCERT, there used to be a chapter fifth which was titled Minerals and Rocks.

0:45 This used to be a chapter called Minerals and Rocks. This has been deleted from the new edition. has been removed. But this chapter named Minerals and Rocks is also very important in itself from the point of view of UPSC. So, what do we do? These two-three chapters have been deleted from this new edition. We will cover these. But we will cover these at the very end. I will not leave anything. But we will cover these chapters at the very end. For now we are following the latest edition of NCERT. And from today we are starting a new chapter, Chapter Fifth. Which is titled Geomorphic Processes.

1:31 What are geomorphic processes? And what are the impacts of geomorphic processes ? We will read and talk about all this in this chapter. Look, let's begin. We have understood this much till now. We have already discussed this much about how this meaning of ours came into existence. How the Earth Was Born. We have also understood how the crust of our Earth has evolved. We have also talked about what has been the story of the inner layers of the Earth. We have also read about how our crystal plates, these tectonic plates, have been moving in the past and how they are

2:17 moving today. And we have also understood that this movement of crystal plates , its impact is seen on earthquakes and on volcanoes. If we talk broadly, then we have understood how the meaning on whose surface we live came into existence? How did the Christ of that meaning evolve? What has been the story of the inner layers of that meaning ? How have the crystal plates of that meaning been moving in the past ? And how are you moving in today's date.

3:03 We have read about all these things in detail in the previous sessions and previous chapters. I have had the conversation. In this Chapter Fifth, Geomorphic Processes, we will discuss another question. We will discuss another question. And what is that question? Why is the surface of the Earth uneven? Why is this surface of the earth uneven? Above the surface of the Earth, at some places we can see mountains, at some places we can see plains, and at some places we can see plateaus. Above the surface of this earth, elevations are seen at some places and depressions are seen at other places. The question arises that why is the surface of the Earth so uneven

3:52 ? This question has been discussed in this chapter. And from all the conversations we've had so far, we have come to know that this crust of our Earth is dynamic. This crust of our Earth is not static. This is dynamic. This crust of our Earth has been moving vertically and horizontally in the past and is moving even today. In fact, we also know that this movement of the Earth's crust used to happen at a faster rate in the past. Today, movement is not seen at that rate. This is a very simple and easy conversation.

4:37 We have already read about all this. We know. We know that the Earth's crust is dynamic. It is not static. We know that the Earth's crust has seen movement both vertically and horizontally in the past. And the movement can be seen even today. But the big question is that this unevenness which we see on the surface of the Earth. Variations can be seen. Which forces are responsible for this unevenness? And there are primarily

5:25 two types of forces responsible for the unevenness seen on the surface of the Earth. Which two types of force are responsible ? An exogenous forces. Exogenic forces or also called exogenetic forces. and other endogenic forces. Endogenic forces or also called endogenetic forces. The question arises, what are exogenic forces ? And what are endogenic forces ? Exogenic Forces Big Simple. What are those external forces called which are operating above the surface of the Earth and outside the surface of the Earth? These are

6:11 called exogenic forces. And the others are endogenic forces. What are endogenic forces? What are the internal forces operating inside the Earth's interior, within the Earth's surface, called? Those internal forces are called endogenic forces. A very simple conversation. This unevenness is visible on the surface of the earth. Primary two forces are responsible for this. Which ones? A Exogenic Forces. All the external forces operating outside the surface of the Earth.

6:57 What are those external forces called? These are called exogenic forces. And the others are androgenic forces. What are the internal forces operating inside the Earth's interior, within the Earth's surface, called ? These are called endogenic forces. What are these exogenic forces? And what are endogenic forces? We will read and discuss about all these in detail in this chapter. And we also understand a little bit that there are differences in the internal forces that are operating, in the endogenic forces that are operating.

7:42 These internal forces have their own different intensities. They have their own different rates. And these differences in the internal forces are responsible for the variations in the outer surface of the crust. The variations that are seen on the outer surface are mountains, plateaus, plains, elevations and depressions. The variations that are observed are primarily attributable to the differences in the internal forces. But just now we talked about how not only internal

8:27 forces operate. External forces also play a major role in the unevenness seen on the surface of the Earth. These external forces, these exogenic forces are also operating consciously and continuously. These exogenic and endogenic forces, these external and internal forces, keep operating constantly. And what is its resultant? This results in unevenness on the surface of the earth. It is a very simple and easy

9:13 conversation. Hopefully you must have understood. What are two things you need to remember from now on? That one is exogenic forces. What are all the external forces called? These are called exogenic forces. And the others are endogenic forces. What are all the internal forces called? They are called endogenic forces. If we talk broadly, then these exogenic forces, these external forces, impact the Earth's surface and the relief variations seen on the Earth's surface primarily in two ways. External

9:58 Forces Exogenic forces impact the Earth's surface primarily in two ways. What are the two methods? One is the wearing down of relief and elevations. The relief features that are seen on the surface of the Earth , the elevations that are seen , the raised parts that are seen , the wear down that is seen in them , the breakdown that is seen in them , the particles that break into smaller pieces , they break because of the exogenic forces. For example, let's assume it is some elevation above the Earth's surface. What will be over the period of time

10:44 ? From this elevation, small particles will start breaking off. Breakdowns will begin to occur. The wear down will begin. So, firstly these exogenic forces are responsible for the wearing down of relief and elevations. And secondly, these small particles that are breaking will not remain here here. Now the wind will come, water will come. Agents like wind and water will carry away these particles with them, blow them away. And now these particles will fill up the basins and depressions on the surface of the Earth.

11:32 So, the second thing that is happening because of exogenic forces is that the depressions, bases and pits on the surface of the Earth are getting filled up. If we talk about the primary, broadly speaking, then due to exogenic forces external forces, primarily two things are seen on the surface of the earth. Firstly, the reliefs and elevations wear down. And what is the term used for this wearing down ? Degradation. What term is used ? Degradation. And on the other hand, the base and the depressions on the surface of the earth get filled up. And what is the term used for this filling up ? Agradation. What term is used ? Agradation. Please keep these terms

12:20 in mind as well. Because when you quote these terms in your answer, the answer looks a little more beautiful. Looks a little more beautiful. In general, if we talk about all the relief variations that are seen on the surface of the earth, pay attention to the reason behind erosion in these relief variations. What is the wear down observed in these relief variations due to erosion called ? That's called gradation. what is it called? It is called gradation. The phenomenon of wearing down of relief variations of the surface of the earth through erosion is known as age gradation.

13:06 Broadly, I understood two things, firstly, two forces are responsible for the unevenness seen on the surface of the earth. Exogenic forces and the other is endogenic forces. External forces are called exogenic forces. And the internal forces are called endogenic forces. These exogenic forces primarily change the Earth's surface in two ways: they impact. Firstly, wearing down or degradation of relief and elevations is visible. And secondly, due to these, filling up or aggradation of basins and depressions is seen. What is the name given to the wearing down of relief variations that occurs due to erosion

13:53 ? That is called gradation. This was about exogenic forces, external forces. But there are endogenic forces too. There are also internal forces and these internal forces constantly elevate the surface of the Earth. Let's do the build up. And here let's understand things a little. What is happening on one side? There are internal forces. And these internal forces are constantly elevating the Earth's surface , building it up. But on the other hand, the external forces are wearing down these elevations and causing them to break down. They are

14:38 breaking into small particles. Meaning these two forces are operating in opposite directions. Opposite actions are giving results. The external forces are wearing down the relief features. He is wearing down the elevations. Their particles are being broken into smaller pieces. And the internal forces are elevating these relief features, these variations. doing a build up. And because of this opposing action of exogenic and endogenic forces, variations are seen. In general terms, the

15:26 endogenic forces are mainly land building forces. The endogenic forces, the internal forces, are mainly responsible for building land, for elevating the earth's surface, for building up. And the exogenic forces, which are external forces, are mainly responsible for wearing down the land and wearing down the elevations above the land. Hopefully you have understood that endogenic forces are primarily

16:11 responsible for land building. They are mainly land building forces. And the exogenic forces are primarily responsible for the wearing of the land. They are land wearing forces. And we know that human life or life in general depends on the surface of this earth. On top of the things that this surface of meaning is providing us. And it is very important to understand that this surface of the Earth, this environment of the Earth , this is our nature, we should use it in such a way that we do not disturb its balance and do

16:59 not diminish its future potential. All organisms seen on the surface of the Earth contribute positively to the Earth's environment. They have their own sense within this environment of meaning. But we human beings have damaged the environment of this Earth, the surface of this Earth very extensively. Because due to our needs and our greed we have overused the resources without thinking. And due to this overuse, damage is seen in the environment. Because of this, there is a danger that

17:52 we may not leave enough for the future potential of our earth and for our coming generations. Maybe we shouldn't leave a better environment for them. Whatever this surface of the Earth is, the way it is visible to us today , it has taken a very long time to come into its today's shape, to be formed. But due to our use and misuse, its potential is diminishing at a very fast rate and we need to pay attention. We need to read and understand these things that are happening above the surface of the Earth. There is a need to take precautions so that

18:37 we can minimize the negative effects that may occur and we can leave enough and proper things for our future generations. Look, this is basic conversation. This is the environmental aspect. This is why we should focus on sustainable development. But what is the important thing ? What are exogenic forces ? What are endogenic forces ? What do exogenic forces primarily do? Wearing down of relief and elevations and filling up of basins and depressions. And secondly, these exogenic and endogenic forces are operating simultaneously. It is not that we are operating separately. These endogenic forces are

19:22 primarily land building forces. And these exogenic forces are primarily land wearing forces. If you understand this then the base of this chapter is yours. Before we proceed further, hit the like button on the video. Pressing like is a must. Because that's how YouTube functions. When you press the like button on a video, YouTube considers the video and gives it a slight push. So hit the like button. Share it on your social media platforms, WhatsApp etc. with your friends. Share it with all those who are interested in this and are studying related things. If you have not subscribed to the channel then for sure subscribe to the channel. And if you are capable and want to help, you can help us by clicking on the join button or you can contribute by

20:08 scanning the QR code. Well, now the question arises that what does this term 'Geomorphic Processes' mean? Look, we just talked about it. That endogenic forces are also operating and exogenic forces are also operating. And because of these endogenic and exogenic forces, physical stress is seen on the Earth's materials and chemical reactions are observed. Due to endogenic and exogenic forces, physical stress is seen on the earth's materials and chemical actions are also observed. And because of these physical stresses and chemical

20:54 reactions, changes are observed in the configuration of the Earth's surface. Variations can be seen in it. This whole process, what is this whole process called? These are called geomorphic processes. The endogenic and exogenic forces causing physical stresses and chemical actions on earth materials and bringing about changes in the configuration of the surface of the Earth are known as geomorphic processes. Hopefully you must have understood. The processes that cause changes and variations to be seen on the Earth's surface.

21:45 Who is primarily responsible for this? Physical stress and chemical reactions created by endogenic and exogenic forces. What are those processes called? Those processes are called geomorphic processes. For example, there is a term called diastrophism, there is a term called volcanism. Both of these are examples of endogenic geomorphic processes. Look, the forces that are responsible for geomorphic processes will be called geomorphic forces. Now if we talk about endogenic geomorphic processes. So what do we call the forces responsible for endogenic geomorphic processes? Endogenic Forces. And what will we call those forces that are responsible for those processes, those

22:33 exogenic processes ? Exogenic forces will speak. It is a very simple thing. Hopefully you will understand. So if we talk about endogenic geomorphic processes, what is an example? There is volcanism. What is the second example? There is diastrophism. What is diastrophism? We will understand and read further. We already know about the volcano. Certain forces operate in the interior of the Earth. And the volcano erupts. So what is this volcanism? This is an endogenic geomorphic process. What is this? It is an endogenic geomorphic process. What are geomorphic processes? Hopefully you must have understood. Good. One is endogenic geomorphic processes. What do we call the geomorphic processes that occur due to internal forces

23:21 ? Endogenic Geomorphic Processes. But then there are some processes which occur due to exogenic forces. And they are called exogenic geomorphic processes. As is weathering. Like there is mass wasting, like there is erosion, like there is deposition. You will already know the meaning of these terms if you have read all the NCERT from class six till now. Weathering. Breakdown into smaller particles, wearing down , breaking. Mass wasting: suddenly, due to some reason, a huge amount of material is coming down and flowing. Movement of erosion particles from one place to another; transportation. Deposition: The

24:07 particle that is moving is going to a particular basin, to a particular place, and getting deposited in a depression. Why are all these processes happening? This is happening due to external forces. These are caused by exogenic forces and so what are they called? This is called exogenic geomorphic process. Very simple. The processes that are taking place due to endogenic forces, internal forces, for example diastrophism, for example volcanism, they are called endogenic geomorphic processes. And those processes which are exogenic, that is, those which are happening due to external forces. They are called exogenic

24:53 geomorphic processes. For example, there is weathering, mass wasting, erosion, deposition. If we talk about exogenic elements of nature. So there is water, ice, wind, all these are exogenic elements. Brother, look. Who is applying those external forces ? There is some particle and it is breaking. He might be feeling a little down with himself. Someone or the other is responsible behind it. Let us assume that there is an elevation here and water is continuously coming and hitting it. It keeps coming and hitting me. Eventually, small pieces from this elevation will start breaking off. So what is water? Water

25:40 is an exogenic element. Or there is wind, the wind is continuously hitting ahead, it is hitting at a high speed and has been hitting for years. So what will ultimately happen is that small particles will start breaking off from this elevation. So, what is this wind? This is an exogenic element. He is an agent. There is ice. Let's assume there is an ice cube or a slab. It is flowing like this downwards into some glacier. And next to it, let's assume there is elevation or any other material. Now when this slab of ice hits this elevation, will it erode some material or not ? But it is obvious that he will do it. So what is this ice? This egg is an exogenous element. These are exogenic elements.

26:26 They are capable of acquiring and transporting earth materials. And what are these exogenous elements called in geographical language ? called geomorphic agents. what is it called? called geomorphic agents. So the processes that occur due to those external forces are called exogenic geomorphic processes. For example, there is weathering, mass wasting, erosion, deposition. What is all this? These are all exogenic geomorphic processes. But the elements responsible for these exogenic geomorphic processes.

27:15 Which are generating the force. Like water, like ice, like wind. What are these exogenic elements called ? These are called geomorphic agents. And when these elements are mobile. When these elements are moving. Like the water is moving. The wind is moving. The ice is moving. When these elements are moving. There are mobiles. So they remove these materials. They transport them and deposit them from a higher level to a lower level. So what generally happens is that both the terms geomorphic processes and geomorphic agents are

28:02 used together. In the context of external forces, these geomorphic processes occur due to geomorphic agents. In the external environment. So, until there is a need to specify , both these terms geomorphic processes and geomorphic agents are used together in the exogenous sense. Very simple, you should understand what these Geomorphic Agents are ? Geomorphic agents are that mobile medium. It is a mobile medium that removes, transports, and deposits material.

28:50 For example is running water. For example is ground water. Ground water also erodes the material. You must have read about it. For example are glaciers. For example, there is wind, for example, there are waves, for example, there are currents. What are all these? These are geomorphic agents. This is a very simple conversation. Hopefully you must have understood. Well, these geomorphic agents move because of the gradient. Gradient means because of slope. Brother, it is water, it originated from the mountain. If there is a slope it will flow downwards. When it flows downwards, it will remove and transport a lot of material with it. So, because of the gradient, this

29:37 removal, this transportation, this deposition of materials can be seen. These are geomorphic agents , they perform these functions. Secondly, gravity also plays a very important role. We know that gravity is a directional force. And gravity tends to take everything towards down slope movement. It pulls it downwards. And because of this gravitational stress, indirectly waves are activated, tides are activated , winds are activated. So if we look broadly, one is gradient, one is slope and the other is gravity, both of these are responsible. These are geomorphic agents, for their mobility, for their

30:24 movement. If there is no gravity and gradient then mobility cannot be seen. And if mobility is not seen, this wind, this water, this ice , these waves, these currents, if they are not mobile, then erosion will also not be seen, transportation will also not be seen, deposition will also not be seen. So, gravity and gradient play a very important role in the mobility of these geomorphic agents. And when these geomorphic agents are mobile, erosion is observed. Only then can transportation be seen and only then can ultimately deposition be seen. So gravitational stresses are as important as the other geomorphic

31:10 processes. Gravity is the force that is keeping us in contact with the surface and it is the force that switches on the movement of all surface materials on Earth. All movements either within the Earth or on the surface of the Earth occur due to gradients. All the movements seen above the Earth's surface or inside the Earth's surface are ultimately caused by gradients. The gradient is primary. Gravity has its own role. Like wind will flow from high pressure to low pressure areas. Water will flow from higher levels to lower levels or a glacier will be visible.

31:57 So this gradient and gravity play a very important role in the mobility of geomorphic agents like wind, water, ice, wave, current and their movement and when there is mobility in them, only then erosion is seen. Only then can transportation be seen. Only then can deposition be seen. If these geomorphic agents are not mobile then there will be no erosion, no transportation and no deposition. After this, we talk about the endogenic processes. We will talk about endogenic processes in the next session. Till now, you should understand these basic things, this basic structure. If you have any doubt, ask by commenting.

32:45 Thank you very much.