 Now we come on the next level population organisms of same kind same species Living in an area are called a population for example here in the picture Precisely you can see different deers which are living in a particular area all of these deers in this area The same species will be called a population because the population of Pakistan for example is about 17 crores about 173 millions All of the people which are living in Pakistan People the human beings even you may it may interest you In the Germany people usually have their their cats and dogs as their pets When they calculate their population they look at the this many people This number of cats and this number of dogs So cats and dogs all of those cats and dogs living in Germany are like one population All the cats one all the dogs one the human beings maybe the lions maybe the deers Maybe the plants of a specific type and so on Now biologists have to study the populations That is they have to look at the interactions between population with different organisms Which are making that population for example interactions between males and males Interactions between the females and females between males and females Between child and adult and so on Because when they have when they are studying these interactions They get to know that what could be the next behavior of a particular part of population That can affect the same population that can also affect the other populations So study of population is also a very important part Now we look at next level which is called community Various populations living in the same area at the same time are called community For example here in the picture you can see there are various plants There are various large huge trees there are a lot many buffalos there are lions Now every part of these this particular area the lions makes one population The buffaloes makes other the small plants the grasses makes other and the trees make another population But because all of these populations are living in the same area They have to interact with each other when they are interacting with each other Maybe communicating maybe as you know that lions will eat the buffalos And if there are deers they will eat the deers these deers will eat the grasses Maybe they will eat the leaves of different plants they are interacting with each other Their interaction is also very important For example if in a particular area in which we are growing crops not like this But an area where human beings are also living and we are growing crops In that area if rats are increased in number they may eat up various parts of our crops And with the result because of the increase in the number of rats human beings will be affected because their food will be reduced And also if there are lot many other birds which are also eating those foods But in lesser quantity they will also not get their food and their number will also be reduced Means that the interactions between community are need to be studied Because if we don't do it the result may be sometimes in a disaster There is an example from China if I am not wrong they have to control their pests For controlling their pests they introduced sparrows that pest was actually a dragonfly And they decided to introduce sparrows in their feeds When they introduced sparrows the number of sparrows was increased They eaten up all the dragonflies and their crops were temporarily protected from the attack of the dragonflies But what was the result? The sparrows increased in so enormous amount that they eaten up all their crops And crops were destroyed even more So interaction between the communities is also important when we are handling with the real life problems We were talking about the population Populations makes communities In communities various populations interact with each other If we look at lot many communities they also have to interact with the abiotic factors Those factors which are not living For example if the lions they are living inside an environment Various plants which are living in a forest They also have to interact with the soil in that particular area They also have to interact with the they have to deal with the temperature of that area If temperature increases their functions will be affected They also have to interact with the waters in the water bodies They have to deal with the humidity If this is increased or decreased their function may be disturbed, may be changed This interaction of biotic factors, the living organisms, the living factors With the abiotic factors in an area is called an ecosystem There are different types of ecosystems present in the body There is an ecosystem in which communities are interacting with their abiotic factors There are different types of ecosystems in the world Like the forest ecosystems in as you know maybe you have seen the National Geographic Which shows you different types of forests in which there are lot many trees There are lot many small plants, there are large plants There are very very small animals like shrews and say reptiles There are very very huge and large animals like elephants There are different types of animals which are predators like lions Which actually eat upon other organisms They also deal with the abiotic factor, temperature increase, decrease In daylight for example temperature is increased And they may have to stay for some time inside the dens somewhere else Just like that if we have rats and they are living in a desert ecosystem Desert is a specific ecosystem which is very hot when sun comes in the day And they become very cold when sun goes down in the evening So rats have to deal with very high temperature in the day They deal with it by say hiding themselves under the rocks So they are interacting with the temperature, they are interacting with the rocks This makes the ecosystem, now there are very complicated ecosystems Like a lake or a pound in a lake There are different types of organisms which are living Because on the upper layer of lake there is very high temperature in comparison to the others Because this is directly exposed to sunlight In the second layer there is less temperature In the third layer there is cold temperature So in different regions of a lake different types of organisms can live, can manage living there Just like that ocean itself is a very complicated ecosystem In which different organisms are living at different levels At very cold temperature with minimum amount of oxygen Sometimes with maximum amount of oxygen There are few oceans even which have a very high rate of salinity That is for example the Dead Sea, Dead Sea have very high salts Somewhere even up to 20% in which most of the organisms cannot survive but few can survive So there are different types of ecosystems, different types of abiotic factors With which the biotech factors have to deal with And those biotech factors that is the living organisms Are specific for their specific ecosystems Because their structures allow them to deal with that particular ecosystem Now comes the last level That is the biosphere, bio, life, sphere, the globe, globe of the earth Because you know, we know that earth is rounded We call it a sphere, biosphere is the living part of the world All the living organisms, all the ecosystem Anywhere where the life can exist Collectively called the biosphere Life even exist in the Antarctic region Where there is too much cold Life may sustain itself in the deserts Where there is too high temperature, too high humidity Life may sustain itself in the oceans Which are very deep At their depth there is a very high pressure But life sustains here Because living organisms have certain which are living in those environments Have specific characteristics to deal with When we collectively study all of these relationships Of this living world All consist of all the organisms, living organisms present on the planet earth We call them biosphere And they have to interact with their environments So this is the reason that we have to study the interactions of Or we can say we have to collect the interactions of All the organisms with their abiotic factors So this is about the levels of organizations in life From atom to biosphere