Free Biology NEET Video Lectures for Biodiversity And Its Conservation

00:00:44 Hello dear students, welcome to the IIT PAL series of biology. I am Rikisha Bahomeic PGT Biology at Kendra Vidala sector 2 A Ripuram New Delhi. In continuation with our last session where we covered some of the topics of the chapter biodiversity and conservation of class 12, we will further cover the remaining portions of this chapter in today's session. Before beginning, let us have a quick recap of what we did in the last session. In the last session, we discussed the following topics. Concept

00:01:21 of biodiversity. Biodiversity is a compressed term for biological diversity which was given by Walter G. Rosen and popularized by a sociobiologist Edward Wilson in 1980s. Biod diversity refers to the variations and variability among the living organisms present on this earth. Then we covered the levels of biod diversity. The major levels of biodiversity are genetics, species and ecological biodiversity. There are three levels of biod diversity and we have discussed about them in our le last session. We have also seen the total

00:02:01 number of estimated species which are identified and also the estimate of those which are unidentified. The identified ones have been recorded and published by IUCN International Union for conservation of nature. According to the 2004 statistics, we have slightly more than 1.5 million species on this earth and the unidentified we follow a logical estimate given by a scientist Robert May which puts the estimate about 7 to 8 million of total species present on this earth. Then we have also seen about the

00:02:39 trends in global biodiversity. We have seen that tropics are more biodiverse as compared to temperates. And if you followed the last session, you must be knowing the reasons why tropics are more biodiverse than temperate. Then we have also covered the biod diversity present in our country. India is among the 17 mega diverse countries of the world because of its rich flora and fauna. Then we looked into the latitudinal gradients in pattern of biod diversity. The latitudes are the imaginary lines

00:03:15 which are on the earth and uh it helps in locating a place properly. So as we move away from the equator we see that the biodiversity or the species diversity keeps on decreasing. Then we have also learned about the species area relationship which was given by Alexander van Hanold. And in this uh he plotted a graph to show the relationship between species richness with the area which is explored. The curve come to uh come out to be a rectangular hyperbola. And lastly we studied about the importance of species diversity. If

00:03:54 we follow certain analogy as given by rivet popper analogy we can uh compare or we can generate a perspective on what importance the species or species diversity hold for us on this planet. So now let us begin with today's topics. So what will we study today? Today we will study about loss of biod diversity. Causes for loss of biod diversity. Why should we conserve biod diversity? What are the reasons and methods for biodiversity conservation? How can we conserve it? So these are the four topics which we will be dealing in

00:04:34 detail in this session of biodiversity and conservation. And also one more thing which we will cover is the international and national concern for biodiversity conservation. What are the various conventions which are held all around the globe to conserve and protect our biodiversity? So starting with biodiversity loss. Loss is always painful. Usually it is painful and so is the loss of biodiversity. The rich biodiversity which got accumulated over a period of millions of years. If we are losing this biod diversity, it is

00:05:16 detrimental to our sustenance. There is no doubt about continuing loss of species. Although it may be doubtful whether new species are being added or not on this earth's surface by the process of speciation. But there is no doubt about the loss of species. We are losing species each day, each minute. And that is a matter of grave concern for us because the biological wealth of our planet is rapidly declining. Uh for example, the human activities basically they are uh they are accelerating this decline in

00:05:54 biodiversity. One of the example is colonization of tropical Pacific islands by humans which led to extinction of more than 2,000 species of the native birds. the birds which used to live there it got extinct because of the colonization of these islands. So the matter of biodiversity loss is uh is of great concern to us and we need to do something to protect this rich biodiversity. uh at the international level as I have mentioned in my earlier session that there is an organization international

00:06:29 union for conservation of nature IUCN it publishes a red list uh of threatened species red refers to danger any kind of danger and this red uh conotes that these animals are under danger or they are under threat of extinction. So this is the cover page of the book cataloged by them IUC and red list of threatened species and it is uh brought out on a regular basis. The IUCN red list of threatened species is also known as the IUCN red list or red data book or red data list. It was founded in 1964 and since then it

00:07:10 has been regularly publishing the list of those animals, those plants, those species which are facing constant threat of extinction. It is the world's most comprehensive inventory of the global conservation status of biological species. And these are the categories which you can see extinct, EX for extinct, EW for extinct in the wild. Under threatened you can see CR critically endangered, endangered, vulnerable and then nearthreatened and least concerned. So these are the categories which uh are

00:07:46 labeled on the different species of organisms to classify them as per their abundance in the nature. Extinction of species. The IUCN red list documents extinction of 784 species in last 500 years. Earlier also I told you that it is the sixth episode of mass extinction. There has been already five such episodes of extinction. But this one is the most important. And this is most important because it is taking place at a greater pace and this pace is about 1,000 to 10,000 times more as compared to the earlier episode of

00:08:32 extinction and the blame for all this goes to yes you are right to the human activities. In the last 500 years, we have seen so much development and the consequences of development which have led to a detrimental effect on the other species which share this planet with us. This include 338 vertebbrates which have got extinct, 359 invertebrates and 87 plant species which got extinct in the last 500 years. Since 1900 95% of Asia's wild tigers have disappeared. So tigers and lions these are also under threat of

00:09:17 extinction. The number is declining day by day and we need to do something regarding this. Uh in India project tiger was launched in 1973 to conserve the tigers which are present and it has considerably uh helped in reducing the number of their extinction. In 1900 there were about one lakh wild tigers and today there are only 3,200 wild tigers in the world all over. Here you can see the pictures of those species which got extinct in the last 500 years. For example, this one you see is the steeler sea cow which was found in

00:09:58 Russia. This is thyloine which which was found in Australia but it has got extinct. Similarly, the bird dodo which uh which was found in Mauricius, it has also become extinct. This is the Pinta island tortoise which is also a subspecies of the Galipe giant tortoises. It has also became extinct. The next one you can see is a zebra-like animal which is known as kuaga. It was found in Africa but it is no more found because it is totally extinct from our earth. And this one is the tiger. This one is the Caspian tiger. And this one

00:10:33 is the Java tiger. They have also completely disappeared from the face of earth. This you see is the Caribbean monk seal and this is the Beiji river dolphin. And these are also under these are also extinct. So you can see there there are lot number of such animals which have got extinct and this extinction is much more in the last 500 years because of the human activities. Now coming to threatened species. After uh after having a glimpse of the species which have gone extinct, let us understand about the threatened species

00:11:10 because we cannot do anything about those species which have gone extinct. But we can surely do something for those species which are under threat. So here you can see that under the threatened category there are three subcategories critically endangered, endangered and vulnerable. And there are three criteria which makes them into this which puts them into their respective categories. What are those three criteria? Number one, it should have a projected population decline of greater than 80% over the next 10 years or three

00:11:44 generation in the case of critically endangered, 50% in the case of endangered and 30% in the case of vulnerable. Similarly, a global range of less than 100 kilome square for critically endangered, 5,000 kilome square for endangered and 20,000 kilome square for vulnerable. A stable global population size of less than 50 individual in case of critically endangered, 250 in case of endangered and thousand in case of vulnerable. So these are the species which are under threat and we need to conserve them. We

00:12:22 need to protect them. Uh the examples being mountain gorilla, blue whale, polar bear, black rhino, brown kiwi, African elephant, lion, green sea turtle, California uh condor. These are the examples of the threatened species and there are many more such threatened species. More than 15,500 species worldwide are facing the threat of extinction. Among them, 12% are the bird species, 23% are the mammal species and 32% are the amphibian species and 31% are of gymnosperms. So this indeed is quite clear that we

00:13:05 are losing our rich biod diversity at quite a high rate and the one who is responsible for it is the human beings. So what are the causes of biodiversity loss. You must try to remember you must try to see and analyze what are the reasons for biodiversity loss. If we see since the time we started developing the humans they have engaged in so many activities like deforestation, over consumption of resources, pollution, agriculture, plantation and all these have adversely affected the rest of the species. So the causes of biodiversity

00:13:46 loss actually can be categorized into four and so it is also referred to as the evil quartate. What does this evil quartetate comprise of? It comprises of number one habitat loss and fragmentation, number two over exploitation, number three co-extinction and number four alien species invasion. Here the picture also gives you some idea about these things. Habitat loss and fragmentation. As you know that habitat is the dwelling place of an organism and by many activities such as agriculture, plantation or deforestation

00:14:26 for establishing uh settlements or for establishing industries, we are actually destroying the habitat of the organism. Secondly, this picture shows that how people are feeling proud to uh kill a tiger and they are taking photographs. This is the height of overexploitation. We are exploiting, we are consuming them or we are killing them for our entertainment, for our use or overexploitation and this is one of the major reason for biodiversity loss. The next one is co-extinction. You can see a picture of a butterfly and it helps in

00:15:06 pollination. There are some plants which are intricately linked linked with certain species of the organisms of the animals or insects which will help in their pollination and if that pollinator is not present the uh plant will also automatically die off. Similarly the alien species invasion here is the photograph of the water heisent which is usually seen whenever we move across uh in buses or in trains. We can see the water bodies they are covered with so many water highend. It is actually an

00:15:38 example of alien species invasion. So let us look uh let us look at them one by one. Number one, habitat loss and fragmentation. It is the most important cause for extinction of plants and animals because the forest for example is the habitat of so many species of plants and animals and if that forest is cut where will these plants and animals go? Certainly they will die they will perish. The area covered by tropical rainforest have drastically reduced from 14% of the earth's surface to less than

00:16:17 6%. The tropical rainforest which are so biodiverse they are also reducing earlier it was 14% of the earth's surface and now we are left with only less than 6% of the forest the Amazon rainforest which I mentioned in the earlier session that these are known as the lungs of our planet they are being cut and cleared for cultivating soya beans or for conversion to grasslands for raising beef cattle these are the petty reasons because of which we are destroying the biodiversity of such rich forests. Human activities again

00:16:54 contribute to this habitat loss and fragmentation, pollution, contaminating the area, agriculture, settlement, we certainly need land and we will clear the forest for that. These all are degrading many habitats and breaking them into smaller fragments. Fragmentation means when we are breaking down a particular land into smaller areas for our uh benefit for our use like in agriculture or in cultivation or for setting up of industries. This fragmentation is particularly detrimental to organisms which are migratory inhabit migratory

00:17:32 birds and those animals which require large territories. For example, the top carnivores like tigers, lions, they require a large area and if the area is divided into smaller areas and used for some other purposes, they will suffer. The next one is overexploitation. Overexploitation. This I would begin with a quote given by Mahatma Gandhi. Earth provides enough to satisfy every man's need but not every man's greed. So the nature has a carrying capacity. The carrying capacity is the capacity of

00:18:10 nature along with its resources to sustain a particular number of species. But if we are exceeding that carrying capacity, we are overusing it, we are over consuming it just for our own selfish motives, then it converts into greed and it will lead to overexloitation. So there are many detrimental human activities which we have discussed which we see in our daily lives. The increased human population basically the population is increasing day by day especially so in India and more population means more burden on the

00:18:46 resources and more burden on the resources will automatically lead to overexloitation. Secondly we are wasting the resources and we are also polluting the resources. We are overh harvesting marine fishes. We are doing agriculture, poaching, hunting. All these activities, mining and burning of fossil fuels, they are adding up and contributing in loss of our biodiversity. Moreover, the science and technology the developments made in the field of science and technology has also added up to this by adding artificial

00:19:25 non-biodegradable materials which remain in the environment for a very long time. So these are the uh detrimental human activities which is leading to overexploitation. Next moving on to the third reason which is the alien species invasion. Alien means uh something some organism which is which does not belong to a particular area. So if alien species invasion refers to an organism which has been brought from some other land into our land and it has started invading that particular area. Why should it start

00:20:04 invading? Yes, you are right. it starts invading or it starts growing or multiplying rapidly because of the absence of any natural predator over them. This is the basic reason. Uh introduction of alien species leads to decline or extinction of indigenous species. So, so they start competing with the indigenous species and it leads to their decline and extinction as well. Example, let us uh have a glimpse of the examples of such examples of alien species invasion. Number one, invasive weeds like parthenium, the commonly

00:20:43 found carrot grass, lantenna, water heisen. These has posed threat to our native species. Some of these species were indeliberately exported with the uh items which we ex which we imported from other countries and some of them we have deliberately introduced for example water heisenth as an ornamental plant because of its mauve colored flowers. So these weeds actually they do not have any predator and they start competing with our indigenous species. our indigenous species are unable to compete

00:21:16 and it start showing decline in their numbers. Secondly, the Nile perch introduced into Lake Victoria in East Africa led to extinction of more than 200 species of cichlid fishes. The Nile perch was a predatory fish which was introduced into Lake Victoria and it led to extinction of so many cichlid fishes the smaller fishes. Similarly, illegal introduction of African catfish clarius gallopinus for aquaculture is also posing threat to indigenous catfishes. The indigenous catfishes are again facing competition

00:21:52 with the African catfish. The farmers prefer them because they easily grow and they grow rapidly and they are cheap. So they are using these fishes, they are introducing them into their lakes, into their ponds illegally and this is posing threat to our indigenous catfishes. So these are the some examples of alien species invasion how it is leading to loss of biodiversity. Uh the next one is co-extinction. Co-extinction. Co- means mutual. If an organism if two organism are in a relationship which is mutual

00:22:28 and they are totally dependent on each other obviously if one species is extinct the other one also will get extinct. This is what is known as co-extinction. Species interaction in some organisms are tight onetoone relationship that is they have co-evolved with time and their interaction is of such that they will not live if any one of them is not present. For example, a given fixed species can be pollinated only by its partner wasp species. The female wasp uses the fruit for ovosition and also

00:23:05 nourishes its larvae by developing seeds within the fruit and in turn it gets pollinated. The fixed species in turn gets pollinated. So this kind of plant pollinator mutualism is also vulnerable to co-extinction. If the vast species somehow becomes extinct, the fixed species will also start declining. This is what is referred to as co-extinction. So we have studied about four causes of biodiversity loss. Number one habitat loss and fragmentation. Number two is alien species invasion. Number three is

00:23:41 co-extinction and number four is overexploitation. So these are the four reasons of biodiversity loss. In order to find out a solution we should know what are the causes of that particular problem. So when we know the causes of these uh problem of the problem biodiversity loss, we should be in a better position to introspect and find out the solution of how to conserve our rich biodiversity. But again why should we conserve biodiversity? Again I would uh like you to recall the question which we discussed in our last

00:24:21 session that what is the importance of a species in an ecosystem? A species in an ecosystem can be of importance of great importance. Such species are the keystone species on whose survival the survival of other species also depend. But it does not mean that only the keystone species are important. There are other species also. All of them are equally important. Initially they may not uh they may not leave any impact any significant impact on the ecosystem but with continuous removal of those species

00:24:58 from the ecosystem it will eventually lead to destruction of that habitat or ecosystem. This we also tried to understand with the help of private popper hypothesis in which we took the example of an aeroplane and how the passenger if start uh popping up a rivet would lead to the destruction of the aeroplane. So uh why should we conserve biod diversity? Biod diversity should be conserved because of many reasons and these reasons can also be categorized into three broad groups. First is narrowly utilitarian. The second one is

00:25:39 broadly utilitarian and the third one is ethical. So what do we mean by narrowly utilitarian? narrowly. If we are narrow-minded and if we want to see only our uh motives, if we want to see only our gains and benefit, then also we can see that biodiversity is very important for us because it gives us a lot many direct tangible or economic benefits. We get food from the different plants and animals. We get cereals, pulses, fruits, vegetables, spices. We get wood, firewood, timber for construction and

00:26:17 other construction materials. We get fiber, cotton, linen, hemp, jude. We get so many industrial products which are used in industries for producing different items, tannins, lubricants, dyes, raisins, perfumes. We get medicines and drugs. All these are the direct benefits which we can see. These are the material benefits which we directly use from the biodiversity we have. So these are put under narrowly utilitarian. The other one is broadly utilitarian. If we have a broader vision and if we try to analyze the use of

00:26:55 biodiversity then we see that there are innumerable indirect or non-tangible ecosystem services which are provided by this biodiversity to us. For example, production of oxygen by trees in a forest. Pollination, seed dispersal, forest act as carbon sink to reduce the air pollution. Whatever carbon emission is there in the air, all gets absorbed by these forest. We have clean drinking water. The nutrient cycle which operates in the nature which is helping us in the in getting that mineral element or

00:27:32 nutrients from them. Uh and uh lastly the cultural and aesthetic pleasure which we derive after looking at the at the rich biod diversity. Walking through a lane green lane uh watching these stars watching the birds singing all these are the aesthetic pleasure which we are getting. We we are we are able to do recreation because of this. So these are the broadly utilitarian uh things which we are getting from our biodiversity and if we start putting a tag on them we will not be able to afford any of them. Be it production of

00:28:11 oxygen be it pollination seed disposal be it absorption of the carbon emission of the pollutants or be the provision of clean drinking water. It will actually cost us a lot and it will not be within the reach of everyone to afford these resources. So we should value these resources for the intangible benefits which we are deriving from them. Coming to the ethical one, man is a thinking being and being thinking he also has a system of values, norms and ethics. uh and these ethics guide us that the

00:28:52 organisms which uh which share this planet with us also have an intrinsic value. So uh there is an intrinsic value to all living organism they also have a right to live like us. So as for morals and ethics also we should not overexploit them for our petty gains. We being a part of nature also owe something to all the fellow species which are present on the earth. It is our moral duty to care for their well-being. And we should also pass on this biological legacy to future generation. This is what is referred to

00:29:29 as sustainable development. We cannot undermine development but we should wisely use our resources so that it can be handed over to the next generation. There should not be a scenario where our children are not able to see tigers or lions just because they are becoming extinct and we are not in a position to conserve them. We should not deprive them of the nature's beauty of the recreation which they renders to us. Uh similarly nature worship as is also a part of our culture and religion and

00:30:05 which mandates us to worship the nature rather destroy it. So these are the reasons because of which we should conserve biod diversity. Next moving on to the methods of biodiversity conservation. So let us recapulate again. First we discussed about the loss of species on the earth. We enumerated the facts of IUCN and then we moved on to the causes of biodiversity loss and then we discussed what are the importance of the conservation of biodiversity. Why should we conserve biodiversity? What do we get

00:30:44 out of it? Now what should we do or what steps are being taken? How do we conserve biodiversity? Biodiversity conservation can be further classified into two types. Insitue conservation and exitu conservation. In situ conservation again as you can see in this table that biodiversity hotspot, biosphere reserves, national parks, wildlife centuries, sacred groups all these are included in the insitue conservation of biodiversity. The exitu conservation it enlist zoological parks botanical gardens wildlife safari parks again the

00:31:27 newer methods like invitro fertilization tissue culture cryopreservation of gameamtes seeds in poland banks and seed banks so what can you make out of this chart can you guess what is the meaning of insitue conservation by the names which have been listed here and what is the meaning of exitu conservation Let us see them in more detail. In situ conservation, when we conserve and protect the whole ecosystem, its biodiversity at all levels, genetics, species and ecological will be protected automatically. This is

00:32:07 the principle behind in situ conservation that we are conserving the entire ecosystem so that whatever organisms are present in that ecosystem gets protected. It is also known as on the site conservation. The approach is in situ or on the site conservation where species are facing the threat of extinction. Once we identify the particular area where there is a threat of extinction, we can declare it as a as an area which needs protection on the side. Conserving all the biological wealth seems unrealistic and

00:32:47 uneconomical to many nations faced with the conflict of development. So development we are at the crossroads where we are we want development and we also want to restore our environment. So it becomes very unrealistic and uneconomical for many countries to do or to create a fine balance between them. But the development will be of no use to us if we are not able to conserve the nature. If there is no environment, if there is no organism, we will not be there. our sustenance will also come under danger. So we need to strike a

00:33:25 fine balance between development and conservation of nature. There are number of species which are waiting to be conserved and this far exceeds the conservation resources which are available with us. Eminent conservationist so have addressed this problem by identifying biodiversity hotspots. Hotspot again hotspots are certain areas which require immediate attention or immediate protection. So let us understand what is a biodiversity hotspot. Biodiversity hotspot is characterized by certain features.

00:34:05 Number one, it should have high level of species richness. There should be species richness means different type of species are present in that particular region. It should have high degree of endemism. What do you mean by endemism? Endmism refers to the uh animals which are present animals or the plants or any species for that matter which resides in that particular region which is found only in that particular region and nowhere else. So high degree of endemism is also a characteristic of a hot

00:34:41 spot. And thirdly they are facing enormous threat of destruction. So these are the three basic criterias for classifying or characterizing a region as a biodiversity hotspot. Number one, it should be rich in species. It should have high degree of endemism and it should be under enormous threat of destruction. Initially 25 biodiversity hotspots were identified but later 10 more have been added and bringing it to a total of 35 hotspots currently. So currently we are having 35 biodiversity hotspots all over the world. Uh one more

00:35:24 important feature about these hotspots are that these hotspots put together cover less than 2% of the earth's land area. But if we strictly protect these areas, it can reduce the ongoing mass extinction of species by about 30%. Which is a great figure indeed. So these hot spots since they are so rich in diversity, they are so rich in species and that to endemic species, if we are able to conserve them, we can reduce the ongoing mass extinction by 30%. India is a mega diverse country and it also has many number of hot spot. At

00:36:08 least four biodiversity hotspot have been identified in India according to the present data. Eastern Himalayas, Indo-urma, western gads and the sunda land in Indian malayan archipilago. These are the four biodiversity hotspot. India is bestowed with rich diversity and these regions are the most rich in diversity and they are harboring the endemic species within them. So these regions is eastern Himalayas, Indobma, western gard and sundaland in India, Malaya archipelago. These are the four biodiversity hotspots of

00:36:50 India. Uh so let us understand the institute conservation method. One is the biodiversity hotspot which we have discussed. Uh the rest involves uh the protection of natural habitats which are known as protected areas. Protected area network include biosphere reserves, national parks, wildlife centuries and sacred groups. India has 18 biosphere reserves, 102 national parks and 515 wildlife centuries. So let us try to understand what is the uh what are these biosphere reserve. Biosphere reserves were

00:37:35 actually established under UNESCO's man and the biosphere program. These are a series of protected areas linked through a global network intended to uh demonstrate relationship between conservation and development. So bas reserve is actually uh an area which is labeled so and this include the conservation of the species as well as developmental activities like educational activities, research is also done in the biosphere reserve and the tribal people also live there. There is a settlement also. So it is like

00:38:13 connecting the nature with the man. So if we see the diagram, the biosphere reserve can be categorized into three regions. We can uh demonstrate uh what a biosphere reserve comprises of with the help of these concentric circle. This is the core area. This is the buffer area and this is the manipulation zone. The core area is strictly for the preservation and conservation of the animals and the plants and all the species of that particular area. The buffer zone is for educational and research purposes in order to find

00:39:12 out more measures for their conservation and this one is the manipulation zone where the tribal peoples and people who participate in the conservation of biosphere reserve reside. So this is how the biosphere reserve is like a relationship between conservation and development. Secondly, national park is also an area which is having adequate ecological, faal, floral, natural or zoological significance. Wildlife centuries are also like national parks but there are certain rights of people which are

00:39:47 granted here. There is some freedom or autonomy to the humans who can go and who can live there. Sacred groups. Again the concept of sacred group is related to our culture to the religion to to our religious practices. These are certain trackcts of forest which are venerated which are woripped and given total protection by a community because of religious or cultural connotation. Examples of them are Kasi and Gentia hills in Megalia, Arai Hills of Rajasthan, Western Gat regions of Karnatak and Maharashtra,

00:40:24 Sguja, Bastar and Chanda regions of Madhya Pradesh and there are many such innumerable number of sacred roofs all over India because Indians they used to believe in nature and they used to worship nature which is a part of their uh culture and their religion. Next coming to exitu conservation. This is a picture of the Delhi zoo. So the zoos uh are uh classified under the exitu conservation. What do we do in this approach? The threatened species they are taken out from their natural habitat and placed in special

00:41:03 sitting setting where they can be protected and given special gear. So those species which are threatened they can no longer be protected in the environment in which they are currently living. So they are taken out of that particular area and they are they are protected under certain special settings where they can be u they can be given the resources which are required for their survival. Examples of exit conservation are zoological parks, botanical gardens and wildlife safari parks which you all are

00:41:37 uh well familiar with. Uh exitu conservation recently has also advanced beyond keeping threatened species in enclosures. Earlier exit conservation uh referred only to keeping them in enclosure in cages or in places where there were restrictions imposed on them. But now with the advances in technology we have developed certain newer methods for their protection. For example, gameamtes they can be preserved by cryopreservation. Cryopreservation is a technique by which the gameamtes can be uh preserved in under very low

00:42:17 temperature. of about minus 193° CC under liquid nitrogen and uh these gamts can be later used under under viable conditions. These gamts can be later used even after many years. We have invitro fertilization under laboratory condition of those animals whose numbers are declining. We can do tissue culture for propagation of plant species. Uh the meristematic tissues they can be taken and they can be kept in a nutrient medium. They can be provided with such a medium which will help in their growth and small

00:42:56 plantage can come out of it. In this way we can do micropagation of plants. Then there are seed banks and polen banks which again uh like the game can be preserved and kept uh so that they can be used in future. Then there are captive breeding for the animals uh so that uh the they can their population can increase. So these are the methods of exitu conservation uh which includes the zoolological parks, botanical gardens, wildlife safari parks and the latest method of invitro fertilization, cryopreservation,

00:43:34 seed bank, poland banks and captive breeding. Now next moving on to our next topic which is concern for biodiversity conservation at national level. Actually, India has been a pioneer in uh showing its commitment towards protection of nature because India is home to world's largest wild tigers population. It has got unique assemblage of globally important endangered species. We have so many endangered species present here like Asiatic lion, Asian elephant, onehorn rhinosaurus, gangic river dolphin, snow leopard,

00:44:14 Kashmiri stag, dugong, gial, great Indian bustard, lion tailed macau. Uh so we have many uh protection act for them in place. Wildlife protection act 1972 which has been modified from time to time. It is further complemented by other such acts for Indian forest act 1927, forest conservation act 1980, environment protection act 1986 and biological diversity act 2002 along with the scheduleul tribe and other traditional forest dwellers act 2006. So India has been taking initiatives for conservation

00:44:53 of nature and conservation of all species alike. Let us look at the biodiversity conservation efforts at international level. Biodiversity conservation is of great concern to everyone around the world and so many conventions are organized every year. Some of the prominent conventions I have mentioned here in this table. Ramsar convention it is also known as convention for the wetlands. Wetlands are the areas which are completely saturated with water and so the conditions there are which is feasible

00:45:25 for the growth of biodiversity. But these wetlands are also under threat and so is the biodiversity within them. Then sites is the convention of international trade in endangered species. It was endorsed by 118 countries in 1973 to ensure that the international trade in the plants and animals does not threaten their survival. The third one is the earth summit. It is known as the convention on biological diversity which was held in Rio de Janeiro in 1992 and it called upon all the nations to take

00:46:01 appropriate measures for the conservation of biodiversity and also sustainable development. It is because of the earth summit that we celebrate 5th June as the world environment day every year. Then recently in 2002 a world summit on sustainable development was held in Jonasburg South Africa where 190 countries pledged their commitment to achieve significant reduction in current rate of biodiversity loss. With this let us discuss some of the questions which I gave you in the last session. Number one, primary

00:46:38 productivity varies from ecosystem to ecosystem. explain. So primary productivity is the productivity which is related to the plant biomass production in plants and if there are more plants they will be able to photosynthesize more and there will be more productivity. So obviously it depends on the plants number of plants which are present in the different ecosystem. Primary productivity depends on the plant species inhabiting the area and their photosynthetic activity as well. apart from various other environmental factors

00:47:11 which you will study in the photosynthesis topic. Uh the next question was to find out what is a tree line. What is a tree line? Actually when we go up an altitude beyond a particular height you will find no trees uh except the shrubs and herbs and that particular point is known as the tree line. the altitude beyond which there is no tree seen. Next question was uh can you give any one example based on your day-to-day observations showing how loss of one species may lead to extinction of others? Uh in today's session we have

00:47:52 covered co-extinction and you will be most probably able to answer this. The most common example is of the plant pollinator relationship which is seen between a fig tree and wasp. Next question. Do you think that more biod diversity enhances the chances of a community to remain stable or resilient under changing environment situations? How? Obviously we have seen this that more is the biodiversity more is the chance of a particular community to show resilience or to show stability. So uh this has been verified by David

00:48:31 Tilman's experiment who used outdoor plots and gave evidence uh to show that more species diversity there will be less fluctuation in productivity per year and he also showed that uh they will show more resilience and there will be more biomass generation if there is more species present in that particular community. What are the major causes of species loss in a geographical region? This also we have covered today that there are the evil quartetate. There are four major reasons for biodiversity loss. Number

00:49:08 one is habitat loss and fragmentation. Number two is overexploitation. Number three is alien species invasion. And number four is co-extinction. How is biodiversity important for ecosystem functioning? Biodiversity is important for ecosystem functioning because it renders stability. It renders productivity. It me it ensures ecosystem health and it also provide resilience to that particular community. Among the ecosystem services are control of floods and soil erosion. How is this achieved by the a by the

00:49:51 biotic component of the ecosystem? Uh control of flood. So the question is that the ecosystem services uh also give there are so many ecosystem services but here the question is focusing on control of flood and soil erosion. We know that flood uh control of flood is carried out by the uh by retaining water and preventing runoff of the rainwater. The litter and the humus of the plant the top soil if it is rich if it is full of humus it can retain the water and it will percolate down. So the probability of floods will decrease.

00:50:26 Similarly soil erosion the roots of the plant they hold the soil and they also reduce the probability of soil erosion. Next question. Can you think of a situation where we deliberately want to make a species extinct? How would you justify it? In the recent years, we have been fighting with many disease-causing organism and in that attempt, we are also leading to decline of their numbers. So, we are trying to eradicate the disease-causing organism like smallox, virus and polio etc. And as these organism on justifying them

00:51:04 we will say that as these organisms are not essential component of any ecosystem losing one or few such organism would not affect the functioning of an ecosystem much. Uh with this uh I would uh lastly summarize what we have done. We have learned about the loss of biod diversity. We have learned about the causes responsible for the loss of biodiversity. We have also learned how to conserve biod diversity. We saw the two methods in situ conservation and exitu conservation. And then we have discussed the question answers from the

00:51:42 NCERT and the questions which was given in the last session. Uh here I would like to end this chapter with a quote that don't like don't let species go extinct because in this world we are we are all linked. Thank you so much. [Music]