hi there everyone and welcome back to national fire biology mir3 life on Earth today we're moving on to kyria 2 which is distribution of organisms and it's a fairly quick key area we should get really quickly so to start off with we are going to look at two new definitions for you a biotic and biotic factors now these really define where organisms will live a biotic a biotic factors are very very important and we're going to look at what these actually mean so to start off with a biotic factors abiotic factors are known living variables the influence where organisms live so you have some examples here such as light intensity temperature soil pH and the moisture level of soil so the main thing here is that these are not living so light intensity temperature pH moisture they are not a living thing ok so they are a biotic one thing to remember as well is if you're asked to give an example of an e biotic factor you have to use the right terminology so you can just see light you have seen late intensity temperatures fine pH and moisture but late there's one or some people I can get that confused with so these nonliving factors can influence where organisms live for example a plant if the light intensity is not good enough then they cannot live there what you all need to know is how to measure these factors of both abiotic and later on biotic and what you really need to focus on is how to measure these what can go wrong and here you can avoid any mistakes so in order to measure a biotic factors we're going to look at light intensity first basic simply you can use a light meter to measure light intensity so if you've had a good one of these in class you should hope to find that it's just a meter that you you hold oil software as you point in the direction of sunlight and it gives you a reading of life in ten states and now it's a simple measurement of it in rent what I value then has some problems that can occur and how to avoid these so for example quick simply if you're using a light meter do not cast your shadow or anyone else shadow onto the light meter because it will give you an accurate reading so you have to be careful where you stand where other people are standing or in the other shade so you get an accurate reading of light intensity next we're going to look at temperature and all the biotic factor so simply if you were measuring temperature of the ear you can use a thermometer if you mentioned temperature soil you can have a temperature probe which you simply dig into the soil one of the issues you can get with this is if you take out the probe and it has some soil left on it especially dump soil and then you go and take another reading that soil that's been left on the probe can give an incorrect reading so you have to make sure between each probe that you wiped down the probe itself to make sure it's accurate in terms of soil you look at pH and moisture levels and again if you've used these very simple there's simply a soil pH level and a moisture proof that you plunge into the soil this is the exact same issue as the temperature probe you to make sure that you get rid of that leftover soil otherwise you'll get an inaccurate reading so now moving onto biotic factors which are different from a biotic factors so biotic factors are living factors living things so if you think you're studying biology biology or bio means living so think biotic planter's living abiotic nonliving sloan's you get on your head you'll be fine so some examples of these biotic factors are things such as predation disease and competition for resources so if you think of this picture here just now of why a zebra predation is a living thing or eating a nonliving thing it's a living factor competition for resources we looked at interior one again living things and fighting each other effectively the one that people forget about and often think is an abiotic factor is disease you have to think the disease is actually a living thing and therefore is there as a biotic factor the other one that we have look at here which is really the same as competition for resources is food availability fighting for these different resources increasing the same as so again you know how to sample biotic factors which is a bit different from a biotic factors so if we have a look at how to sample living things it's obviously different from just picking up the nonliving things such as light intensity temperature pH and that sort of thing hopefully you've had the chance to use quadrats and pitfall traps during your time in class if you're not we're going to be running through these anyway so a Quadra is effectively a set of squares that you can throw and you have to prove randomly onto an area of grassland and use them at current the abundance of plants in that area once at an accurate mean you can have is if you choose where to throw so often you have a big grassy area and you're there to calculate the abundance of theories you have to throw this random a so that you actually get an accurate result of the abundance so you get a good idea of the abundance of disease because if you go and actively look for a bunch of daisies and place the quadrat on top of it that is not gonna give you an accurate reading so it was very important that you fluor place the quadrats randomly quite a common question that comes up the only issue with quadrats is that if you're trying to catch or measure living things is they can simply walk out with the squares that's quite difficult to do so if you're a ham to catch in sake small bugs I think that you use a pitfall trap very simply pitfall traps are used to sample small invertebrates so you can see in this diagram here and faithfully sold trap you can often use a yogurt pot the shopping to dig into the soil have a lid on top of it and small invertebrates will fall into it and you can count them later on to have a a good idea of the abundance of interest in that area one of the things that must happen all in order to keep this hribal key this accurate is that the tracks must be covered to stop ring getting in and also to be disguised because if you have a pot full of bugs and there's not been covered up either the ring can get and can kill everything or birds can go and eat old bugs or they if these birds can leave the box then you have no results you think there's nothing there there could have been quite a lot so this is one thing again common question how you can ensure that such hribal cover up the trap camouflage it to make sure that the box they're vertebrates are not eaten once you've you've used a pitfall trap or if use your quadrant your identifying any sort of organism we need to look at how you can figure it have more organism this's so we look at identification keys as one of these things there are two forms of keys that you could be asked in nitrified biology to use to identify organisms they can be called a branching key or a Pyrrhic stealing key and we'll look at some examples here this would be an example of a normal branching key where you can just see questions going branches and ups I have the answer yes or no or somewhere for a binary answer to each question today and find out what's going on so for example if you're holding a bit of the plant and the first question is is it an animal you'd say no it gives you know what selection says can it be seen by the naked eye maybe say yes and followed these questions and I'll eventually tell you what the organism is all from the exam they will give you some blank questions or blank answers and you have to fill them it's a bit more of a problem-solving take question you'll be given an organism and you break it down into different questions so you can identify them the other foreign key is a speared statement key which comes up very often as well it's effectively the same thing that starts the branching structure you're just getting the question you answer the question and go on to another question so for example here if you have fly if it said body with legs or body without legs you can see work dancers there and then move on to your next question once you go down them you will find out what dorkness and as the you're trying to identify to actually show you what this is is like and what's up questions you can get this is a passed paper question here where you're getting set questions on the physical appearance of an unnamed organism and you have to use these questions as pure state Mickey to get a correct answer so if you were given this organism here and you have to use as pure statement key use the questions and answer the questions to find out what is if you pause I will then go through the answer so you would find that this on the end organism must be a chillip order the reason for that is the first question you look at it and it clearly has more than six likes so you go to question two question two it still has more than eight legs so you go to question four and four you have to choose between one pair of legs parabolic segments or two pairs of likes purple this segment when you eat segments there is one pair of legs on each one so it must be teleporter have a practice of these sorts of questions because they're not too difficult just as long as you're paying attention to what the organism is finally in ask area we're going to look at something called indicator species and what these are are these are different species indicate environmental quality or pollution levels by either being present or absence in the area so often we have a vertebrates and freshwater and lichens for air pollution and we'll look at these in a second so for example wine comes lichens are really good indicator of air pollution levels if you have a very nice clean atmosphere then you tend find a large variation different species of lichen if you have not great level of air quality if you have quite high air pollution you'll find less lichens so this would be an example of an indicator species if you have more lichens there is less air pollution if you look at this diagram here secondly in water there's a couple ones we can look at here you can use fresh water invertebrates in order to indicate what the water pollution levels are like so for example if the water is very clean those fair honey quality and hi oxygen concentration you will find nymphs such as me flying and stone flying however if the river has she had quite a lot of surge or there's been something else going on there's a lot of pollution the billow option concentration aisle contains species such as sludge forms that identikit high pollution again and indicator species a good way of remembering us is sludge one sense horrific so it must be an affiliate part or a pure quality area so that is clear to distribution of organisms so again there's a few things for you to be memorizing definitions if you think of abiotic and biotic and examples of them for the measuring of abiotic and biotic factors you really just need to look at what can go wrong and how you fix them with your pure statement keys and your branch keys have a look at how you can you know construct them or use them to identify anarchism and for the indicator species just think of what an indication pieces is and examples of them in both air quality and fresh water quality so thanks so much for listening folks the next one is going to be photosynthesis and I will get us up fairly soon I will be pouring a bit less for prelims so we're trying to get these uploaded as quickly as possible thanks so much for less