welcome to class time your daily classroom for csec and cape students i'm jerome wright and i'll be starting you off with csec biology and the topic for this session is ecology before i move into ecology i want to do a quick recap of last session class next slide all right so when we met first we look at classification and you define classification we also look at the different types of classification and who can remind me of the different types of classification that there are very good you have artificial natural and you have phylogenetic and we said with artificial classification there was some myth of inaccuracies meaning that organisms were classified and the fact that they look alike and so we realized that that's not accurate because as you use the example with the shark and the dolphin they both have fins the swimming water they look alike but dolphins are mammals and sharks are fishes we also look at the hierarchy of grouping organisms and we said that there are mnemonics you can use like king philip came over for good soup so that's kingdom phylum class order family genus species and based on that we look at common names versus scientific names where we said that common names can be confusing because what we call an organism um by in other cultures it's different for example ginep what we call guinea in jamaica they call it aki in barbados and so when you're in a group of scientists and you're referring to an organism we make known by their scientific name which is universal so whether you are from china japan australia uh when you speak of the scientific name which is made up of the genus and species name then there's no confusion we also look at the five kingdoms in which organisms are classified into all right and we say the plantae animalia fungi protists and and we said that virus is no longer a uh sorry monero a leftover one that um viruses are no longer a kingdom due to the fact that they are not considered to be organism now that we have set the foundation and we have recap we can now move on to today's lesson which is according to be slide is ecology now what is ecology right now ecology is simply the study of the interaction of living things with each other and also their physical environment so when defining ecology we have to make sure that we state that it is an interaction between organisms and the organisms and their environment and so as we navigate through today's lesson these are some of the objectives in which i want you to be familiar with um we define ecology as we have done already and we need to differentiate between um some terms that are used in ecology what do you mean by population versus community what do you mean by niche versus habitat and we need to list at least two abiotic and variety factors that may affect living organism you also need to be able to explain how a name biotic and abiotic factor can affect the distribution of species now moving forward if you're doing ecology you need to know the terms that are used in ecology the jargons the different phrases that are used for ecology one of these phrases is population what do we mean by population when we're talking about population in ecology we have talked about all the members of a species i remember i tell you last week that is never specie this is always species inhabiting a given location so a group of cockroaches that's a specie right a group of pigs within an ecosystem that is a population because it's just one species that is occupying that given location so it sees a population now we talk about community we are talking about different population occupying that given area so no you don't have just cockroaches you have pigs you have birds you have fishes so you have different population occupying that area so population we are talking about just one species community we are talking about different population occupying a given location now a species as we defined last class is a group of organisms that can interbreed and not only do they interbreed but they should produce viable fertile offspring and last week we think about the the mule which is a cross between the donkey and the horse and because a duncan horse is of two different species the mule is considered to be infertile now some other terms is niche when we talk about niche we're referring to the job of the organism within the ecosystem for example earthworms they increase soil fertility when they borrow through the soil decomposers their job is to increase soil fertility by returning the nutrients back to the soil plants their role in the ecosystem is that they provide energy and they also provide food for the the other organisms to to feed and so plants are your producers so niche refers to the role of the organism within the ecosystem like for example um shrimp lobsters those are called scavengers so they feed and they make sure that the ecosystem is clean by feeding on dead plants and animal matter habitat is a place where the organism lives right so the difference between niche and habitat and remember it's not habitant is always habitat now biosphere is a portion of the earth where life exists environment refers to anything that's surround the organism it can be biotic and abiotic factors and we'll look into that later on in a lesson no ecosystem involves the interaction between the abiotic and biotic factors within the community and the ecosystem and how they interact to maintain a balance in the ecosystem now we're going to look at abiotic factors because one or one of the objective is to look at abiotic factors and biotic factors and to see how they affect the distribution of species the ability factors are those physical factors or chemical factors which affect the ability of organisms to survive and reproduce now some of the abiotic factors are these light intensity temperature amount of moisture type of sub sub stratum and we're talking about like soil rocks and availability of inorganic substances such as your minerals supply of gases like oxygen carbon oxygen carbon dioxide sorry and nitrogen as well as ph all those are considered to be abiotic factors they are the non-living factors within the ecosystem now each of the ability factors they can also refer to as limiting factors and these limiting factors they what they mean is that they will detect what type of organism are it takes whatever organism can and will survive in that particular habitat so they are also termed as the limiting factors and on your screen there you can see two different ecosystem and this is what i mean by the abiotic factors being the limiting factor within the ecosystem if you look at the picture on the top you can see it is very lush right a lot of vegetation a lot of plant diversity compared to the picture at the bottom you can see that they're not much plants you know god bless their mother plants you can see you can't even count them all right very scanty now can you tell me two abiotic factors that may be responsible for the difference in both pictures very good you can talk about the availability of water as you can see the top picture right there there must be some amount of rainfall what is available so the plant can actually grow and flourish kind of plants need water for photosynthesis you know so the plants can grow and and look very lovely and nice so you have a dense network of plants yes you have an increase in plant diversity comparing all to the second picture as you can see you can look and see that the ground is very thirsty look at that parched not much water available so only those plants who are able to survive in that conditions will actually thrive in that condition because they're not much water so you see where water availability of water will dictate to the type of plant that will grow within an ecosystem so that's what we mean by abiotic factors can be limiting factors what other ability factors i think can cause this change very good you can look at the soil type from the top picture you can see that the soil type is very fertile so that it can give rise to all these various plants living there while the bottom pitcher you can see that the soil type is not that fertile right not much plant living there so it speaks to the fertility of the soil at the bottom so you see two ability factors availability of water and soil type that can affect um plants living within a given ecosystem and these are some examples of our plants can actually affect our ability factors sorry can actually affect organisms within our ecosystem so low temperature can affect organisms the amount of oxygen dissolved in water can affect the species of fish that lives there a dry environment like the desert will limit the amount of organism living there god not our organism are able to tolerate that harsh condition within the desert so those only those organisms that are able to adapt to that particular environment will survive there process like us will not survive in the desert for very long because our body is not adopted for such harsh conditions now your c6 syllabus asks us to look at soil as a major abiotic factors and we will go into that um just now so soil made up of rocks water air and different components and it's provide water nutrients for our plants as well as it offer encourage for plants it also a home for many organisms like bacteria and fungi welcome back so let's continue so we are on the topic of abiotic factors and we're looking at soil as an abiotic factor that may affect organism living within an ecosystem so there are different types of of soil depends on the textbook that you have it may say three types some so four types but um roughly there are four major types of soil the first one is sandy soil and this soil contains large particles and so they have a lot of air spaces between those particles with that large airspace come the fact that the soil will leash minerals very easily because water tends to drain through very quickly and as water drains through it carries also dissolved minerals with it so those soil particles are very large and so they are not considered to be very fertile because they tend to lose nutrients often as water drains to those soil the advantage with sandy soil however is that they will not water log very easily because they have a very low water holding capacity what that means is that they are the tendency for them to hold on to water is very small so water tends to drain through them very easily then we have silt and silt is basically a midway between sand and clay so they are moderate particles um they're small enough so that they they can have drainage problems but the the particles are water can genes who quite easily compared to clay soil they are normally formed near water bodies and they are also very fertile soil so farmers tend to use them a lot to plant um their crops and that particular soil then we have clay soil and these particles are very very tiny and so what happens is that water tends to be held between these tiny particles by capillarity so they don't drain very readily so those soils tend to be waterlogged very easily because they are poor drainage and so it is not the ideal soil for plants to grow on then we come to the miracle soil which all farmers love or normally call the nickname agricultural soil and that is your loam soil and loam is a mixture of sun silt and clay and so it is a perfect blend for agriculture it drains easily it is very fertile and so on a long soil you'll have a greater diversity of plant and a long soil compared to a sandy soil or a clay soil so a loam soil is a perfect blend we compared all the three different types of soil and you form a miracle soil right there now this picture does give an idea of the particle size for sand silt and clay as you can see for the sun the particles are large and so there are a lot of air spaces between them and so water drains easily for silt as i tell a silt is between sand and clay and so there are a little bit of air space more than the the clay but not as much as the sun and so water tends to drain through more easily compared to clay soil and loam soil now would be a mixture of all three clay soil as you can see you can only see the air species between the soil particles all right so so water does not drain readily through clay soil and there's a lab that you'll do in your lessons where you're going to discover or demonstrate the water holding capacity of three different types of soil know the components of soil now soil made up of components and your c6 syllabus advises us that which you should know the at least three components of soil and their function so we have organic matter and those are your dead and decaying plant matter within the soil you know variable term humus which is made from dead and decaying plant matter and what that does is that it helps to increase the fertility of the soil and it also add nutrients um to the soil and helps you get water holding capacity you have the mineral components of the soil which form the skeleton of the soil those are like rock particles right and they what they do is that they they help to anchor the plant within this the soil and they also um provide the area for water to hold onto in terms of water holding capacity so they also help to hold water between the particles within the soil all right and it gives the soil its texture the coarseness or the smoothness of the of the soil then you have living organism yes within the soil they are living organism they have bacteria fungi earthworms all those are living organism within the soil and they are very much important for the soil earthworms for example they helps to increase the fertility of the soil as they borrow through the soil they increase aeration and so improve the soil fertility as well they have decomposers that helps to break down organic matter and so return nutrients to the the soil water is another component of soil and water is important because one it helps plan for photosynthesis without water the plant cannot undergo photosynthesis as you know water is a by-product uh water salt is a raw material for photosynthesis so the plant needs water for photosynthesis water is also needed in that it prevents the desiccation of soil organism for example the earthworms their body are soft so if there's not too much water you learn about osmosis so water will tend to move from the earthworm to the surrounding and so desiccation simply means drying out of the soil organism then we have soil air and in area talking about oxygen all right so the oxygen is within the soil a component of of air so you know is made up of oxygen carbon dioxide etc but we are more interested in the oxygen within the the air and this oxygen is very important because you know the plant roots are living and once it is living it needs oxygen for respiration more importantly also is that within the soil you have soil organism and this organism needs to respire and so it is important for soil to be very aerated in order for this organism to survive that is why when water the soil is water logged it is very detrimental for the plant yes plant needs water but too much water is not good for the plant because what it does is that it clogs up so to speak the air space is within the soil so the plant roots cannot breathe and so the plant roots die and if the plant roots diet the plant will ultimately die now since we're looking at abiotic factors we're also going to look at the fact that organisms have so adapted to live within their ecosystem so they have a way of so-called working around the abiotic factors in order to survive uh you can remember the picture i show you some slides back about it two different ecosystem you can see even the area that was very dry you still have plants living there because those plants have adapted to live in that particular environment and so for plants they can be classified into four groups based on how they the water is within that particular habitant so you have zero fights these are plants that can live in areas where there's limited amount of water and who can give me an example of those areas that have very little amount of water all right for yes like your desert but in the desert you still have plants living there because these plants are adapted to live in that particular area you have halophytes and these are plants that can live in areas where there's a high amount of salt water and so the soil type they were very salty um like your mangroves which are going to look later on hydrophytes these are considered to be water plants so they live actually in water like your water lilies and now the mesophytes these are ordinary tree plants that you see outside look what the windows the mango tree the apple tree those are my supplies so the living areas where water is readily available not too much not too little but just the right amount now for this lesson i'm going to look at mangroves which are considered to be halophytes and there's a program that tbj is running um i think this thursday at 8 30 we're looking at where the mangroves gone that is a very good program for you to stay tuned to because it helps to tell about mangroves and they're important in the ecosystem so i might tell you to go and stay tuned for that program is very much beneficial to you now when it comes down to mangrove mangrove occurs in what is called zonation so at the water's edge you'll find one type of mangrove and then as you move from the watered edge you'll find another type of mangroves and so forth so they occur in zonation so at the water's edge as you can imagine not much soil right so how do these mangroves manage to live in an area where there's not much soil good they have what is called prop roots and as you can see on a diagram there are roots coming from the the stem all right going down all right normally roots are below the surface of the earth right but with these plants you have the roots coming from the the stem and these are called prop roots and so they help to support the plant because remember one of the function of soil is that it provides anchorage helps to encourage a plant it it you know work in accordance with the roots as well helps to anchor the plants if there is no soil there's no way the plant can actually anchor properly so this prep group serves to keep the plant anchored right and as you know that's the red mangroves and as you go inland you'll have the black mangroves and you can see there are some things growing off the black mangroves and i'm going to go to the the white board to show you um what i'm talking about and for those students who have thought before you know that um leonardo da vinci really has nothing on me when it comes on to join all right so this is my redman grove all right and you have the prop roots so these are what's coming off it so the prop roots now as you go inland you're going to encounter now the black mangroves and as you can see from the diagram you have things coming off from the soil so this is a red and your black now these are called new metaphors all right and it's a quite a big word but what it actually means is just breathing roots and why do they need breathing roots is that as can imagine is close to the water's edge so the soil right there will be very waterlogged all right so what happens that the roots come up in order for the plant to get oxygen and so help the plant to still survive in the waterlogged soil so they have what is called new metaphors or breathing roots further inland you'll encounter the white mangroves right and how the white mangroves manage to survive another condition that particle abiotic factors which is salty water is that they too have breathing roots as well which enables the plants to still allow the plants to get plant roots to get air in the waterlogged soil now how do they overcome the saltiness of the water that they they live in or the saltiness of the the soil because sea water come and wash up so of course the soil is going to be high in salinity what they have is um the red mangroves are what is called a sacrificial root sacrificial leaves sorry and what that means is that with these mangroves what they do is that they the all the excess salt will go into an older leaf does it call sacrificial leaves so all the salt content the excess soil salt that it takes up by the roots will go into an older leaf and these leaves will ultimately fall from the plant and as they fall from the plant they take along with it the excess salt now the black mangroves have what is called salt glands and these salt glands um they excrete actively excrete salt from the the plant so all the excess salt that comes up will be removed from the plant by these salt glands and their leaf and that's for both the the black and white mangroves these are the four type of mangrove it's not mainly mentioned and it's because of the fact that they they live further inland so they are more like our tree um plants so they are not much adaptation for them because they live more inland and those are called button man groves so the mangroves are capable of adapting to the environment in which they're living despite the ability factors which is high salt content within the soil and the fact that there's not much soil and the soil tends to be a water log so they are the prop roots will helps to for the red mangroves help them to anchor in the the water's edge where there's not much soil you have the red mangroves the black and white mangroves sorry have new metaphors that enables them to live in the waterlogged soil they also have salt glands on their leaves to get rid of the excess salt now what about animals animals are also adapted to live in the environment despite the ability factors that might be present for example your fresh and saltwater fish right now the for the freshwater fish they have to contend with a lot of water being um coming into its body by osmosis okay you know there's a lot more the concentration of water outside will be far more than what is inside the organism so they have to contend with a lot of water coming into the body of the organism how do i deal with this is that they excrete dilute urine so a large amount of urine and it is very dilute right so that's how they get rid of most of the water that comes in they also do not drink the the water because already they have to continue with a lot of water moving through the surface of their skin by osmosis salt water fish if they live in salt water they are still fresh you know your grandmother testifies to the lord keep her like like oh jesus keep the fresh freeze in the salt water yes that's very true so if they live in salt water the fish is not salt at all and this is because they actively actively pumped out salt out of their body so they're leaving water that is very salty sea water very salty so they drink they have to drink water because their body constantly lives in water too they see water because the water concentration in their body will be higher than that in the sea and we're talking about water concentration we're talking about water potential the amount of ability for water to move up on a boat right so the water in there but is more dilute than what is in the sea water i should say so water is going to move from their bodies to the sea water and so they have to drink water to compensate for that but their drinking water comes under the problem the sea water is very salty how do they get rid of this excess salt into their body so they actively pumped out salt through their gills and they also um produce very concentrated urine their urine are very salty and that's so they get rid of the excess salt within their body so that's how the fish is uh able to adapt to their their environment despite the abiotic factors that's there all right now you also have biotic factors so biotic factor speaks to the living components of the environment so abiotic non-living like salinity soil type ph temperature right all those are abiotic factors and they or they play a part in the diversity are the distribution of species within an ecosystem but we also have biotic factors which are living factors and these living factors also plays a role in the distribution of species within an ecosystem some of these variety factors are listed but are not limited to you have competition for environmental resources so there's competition between species all right so you have your fighting going on you have availability of food you have diseases caused by pathogens and you also have decomposers all right so these are some of the acidities that are limited to these there are a lot more but for our time you just want to look at at these fuel so talk about availability of food you know everybody needs to eat right living in an ecosystem um nothing much food not much food going around so they're going to be fighting competition for for food so animals require food and food is not um infinite there's there's finite amount that that is available so if you have a large amount of persons in an ear and there's limited food there's going to be fighting that that is going to take place so organisms are going to compete with each other memorial ecology is the interaction between organisms and also organisms and their environment right so species are going to um compete for for food and if there's not enough food to to accommodate everybody then they're going to be migration from that particular um habitat all right if there's a lot of food for everybody they're going to find out there a lot of organism or the diversity of species will increase because there's food for everybody but if there's not enough food then only those organisms are the alpha organism those that can fight and able to defend or whatever will stay those others will migrate to areas where they can find food decomposers are very much vital to the ecosystem in that they recycle nutrients within the ecosystem so they are responsible for returning nutrients to the the soil so an organism dies these decomposers act upon them and return the nutrient to the the cycles and later on when we look at carbon and nitrogen cycle we're gonna see the importance of some of these decomposers so if there's not enough decomposers within an ecosystem of course the soil is not going to be as fertile and so you'll not see as much diversity in terms of plant growing in that air and competition between individuals right as i said with the food organisms are going to compete they're going to compete for water then compete for space all right so a lot of competition will be going on between organism and only this this fitness will survive all right and later on in grade 11 when they do natural selection you're going to learn about the survival of the fetus so those organisms that can be able to survive will move on are reproduced but those organisms that can't really manage that particular environment of course is going to to leave all right so competition between individuals will exist within an ecosystem and finally we have predation so within an ecosystem if an ecosystem is heavily predated of course you're going to have not much organism living there because nobody wants to be eaten right so if if a prey knows that listen over there you know there's a lot of lion and tiger living over there no of course they're not going to congregate there you know because nobody wants to be eaten and of course with predation comes also are listening in terms of the species diversity so the praise will increase and the predators increase and sometimes when it reaches to a point where they the predators can no longer find food they will also migrate so a reduction in predators can lead to an increase in prey and with an increase in prey will also comes an increase in predators because predators are looking for food and freeze don't want to be eaten so they are not going to stay around all right they're not going to stay around and wait for the land to come and eat them they're going to disperse uh so if our air is heavily predated then of course you're not going to find a lot of um praise living there and so the the animal diversity right will decrease right so before i i recap we have homework the last demo was here um students termina they didn't get any homework so i'm here to please the the masses so now i have homer all right so for the homework i wanted to list three methods used by ecologists to should be trapped organism for study all right and you need to list two methods of sampling and and distribution of organism you also need to state two pros and cons for using any one of the methods listed above so you're going to list the method used by ecologists to study or to sample two sampling methods used by ecologists within the environment are in an ecosystem and you need to to state two pros and cons for any one of the method that you have chosen right and so you need to go and do your research so so much a bit of independent learning going up on right there so to recap we look at ecology define ecology we look at different terms in ecology we look at some biotic and abiotic factors and how these abiotic factors affect the distribution of organism within an ecosystem also we look at how biotic factors as well will affect organism living within an ecosystem and both abiotic and biotic factors can be termed as limiting factors meaning that they play a role and will determine or dictate to the type of organism that will live in a given area all right so you can go and review your notes and make sure that you study all right now that's it for today's lesson