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hello this is mr. Noland and in the previous video I kind of walked you through the first five indexes that we could possibly look at in order to calculate for our River project I want to show you now which in this video I just want to talk to you about one of them it's the Shannon miner diversity index the Shannon wino diversity index is almost magic it's a really really cool calculation it's mathematically simple but it's a little bit owner us to put together I'll show you a link in this video where you can go to a website that will kind of show you how to do this shorthand but on what this calculation does is it shows us how diverse the ecosystem is and if an ecosystem is diverse that is a good thing that means it's more stable there's more organisms out there there's more species you know if maybe if we lose one then there are other species that can kind of make up for it so you want a diverse ecosystem that's going to be better all things considered that's gonna be better than in ecosystem which is not diverse so the thing about the Shannon miner diversity index is that we can't use these feeding groups that we used for the other indexes these won't work so instead we actually have to use data from individual species and we have to set up a table now in this date this even if we want to use the the website that I'm going to show you we still have to set up a table at least to do the to write out the species and their number just to keep that organized and and then we can go from there so here's our numbers of some organisms now these are made-up numbers these aren't from a certain year or anything these are just kind of made-up numbers and we are going to pretend that we found 23 non-biting midges 27 viviparous snails and then 12 water boatmen now which species they are doesn't really matter as long as you recognized each one's different species and here's the numbers for them so this is how we need to set this table is with the species a column for number and then four more columns after it and I'll talk about what each of these columns means so in this table what these things mean here's our species this little pie means that percent as a decimal that's what this P I means so we're actually going to calculate the percent as a decimal and then do the rest of this table so let's talk about that first so we have to take all of our organisms and find what are they as decimals now in order to do that we need to figure out what the total is you can't calculate a percent without the total so the total here 23 and 27 and 12 is 62 so that's my total number of organisms so I need to know that in order to calculate any of the rest of this I need to get the total number of organisms and now pi is just the Dement decimal so here's what we mean the percent decimal in this case is going to be 23 divided by 62 23 divided by 62 is going to give us a number that decimal although it's not a percent is a decimal so that decimal is 0.37 1 if we route it to the nearest thousand so that's what our decimal is right there and we can do that for the other ones 27 divided by 62 it's going to give us zero point 4 3 5 and finally 12 divided by 62 it's going to give us zero point one nine ah let's round that to 4 so this is the first step in the Shannon wider diversity index is just to calculate what are the percent decimals of each of these and if we do it right these should add up to one and you'll notice that they actually do they add up to one point zero zero zero so that's the first step is to just find the species the number of each based on the total what is the percent decimal of each one we want around other thousandths so this is where we run into kind of weird spot this Ln is a function it's called natural log the reason why it's Ln is because it was invented by it by a French person and in French the the verb comes or the noun comes first and then the adjective comes after so this is the logarithm of natural so Ln that's why is Ln instead of Ln L but its natural log and it's a function you should find it either on a scientific calculator or on your phone now a good way to test whether or not you're using it properly is to determine the natural log of 0.5 so the way that you would set this up is like this you would say ln natural log of 0.5 equals and then you would actually have to do that so in my calculator what it gives me is negative 0.693 now this number doesn't really mean anything all that this number is is a test to figure out whether or not you're doing it right if you but do this calculation properly you should find that the natural log of 0.5 is negative 0.693 now don't worry about too much what that means this number doesn't mean anything at all it's just a test but what we need to be able to do is to use natural log in order to apply it to these other numbers and where it's gonna spit out a number at the end of this table that numbers gonna tell us how diverse our ecosystem is on a scale from basically zero to around three the higher the number is the better off that is so in order for this to work I have to take the natural log of point three seven one put that here find the natural log of point four three five put that here find the natural log of point one ninety four and put that here so I'm gonna go ahead and sort of pause the video and fill those in so you can see what would it look like for each of those if I used the natural log for that number okay so what I did was for each of these numbers I took point three seven one found the natural log of that number and here's what I get these give us these really weird ugly decimals so negative point zero I'm sorry negative zero point nine and two negative zero point eight three two and negative one point six four zero and these are all rounded to the nearest thousandth once we've done that this is the part that kind of loses people sometimes we're gonna multiply these two numbers together in order to get this one so the way that we can remember how to do that is to just take those symbols just put times that equals so I'm gonna do that for each one I'm just gonna multiply this number by that number and it's gonna get me this number so I'm going to go ahead and pause and we'll do that so there we go I just multiplied 37 1 times negative 0.99 - and I got that number I did the same thing all the way over I just multiplied that by that and I got this number so now this column is filled up this is the easy part I just have to find they're opposites so if I have negative 0.368 I'm just got to turn that into positives over here and then I'm going to add them up and that total is going to be my Shannon Winer diversity index so I'll add those up and we'll talk about what that numbers supposed to mean okay success so what I did was I turned all these into positives and then I added them up and I end up with just a little bit over one so I got one point zero four eight now the way that the Shannon whiner diversity index works is that if it's less than one point five that's a very low diversity if it's between one point five and two point five that's sort of a medium diversity and if it's greater than two point five then that's a high diversity so since I'm sitting at one point zero four eight that's less than this one point five so pretty low diversity so this is the idea behind how to calculate a Shannon Minor diversity index it's not as difficult as it looks but let me show you that the link to this website and that way you can kind of see how you can do this a little bit easier so let me show you that okay so this is that website I'll also send this to you and make this available it's gonna save you a lot of time because instead of having to set up this whole big complicated table we just take our numbers plug them in and I'll show you which one we want to look at that gives us our biodiversity Shannon Winer so we still have to know these numbers 23 27 and 12 but I'll show you how to use this website when you go to this website it's going to give you show you this screen it's gonna ask for the number of species in the sample well we know that that number is 3 1 2 3 species so that's why I'm gonna tell it I'm gonna say 3 submit now it's going to ask for what these things are I don't think you really have to type in the names but the numbers are what you have to type in so if I type in 23 27 and 12 23 712 let's see what happens let's let's the decimal accuracy - let's take that to three digits that way it will give us out to the thousandths so when I do this it's going to give me this this really sort of difficult complicated screen the one that we're gonna look for is we're gonna find Shannon index and we're going to look for the second one that it gives us one point zero five let's see how that compared to the one previously I think that's pretty darn close I think it was one point zero four eight or something like that so this middle one this middle Shannon index right there is the one that we would look for if we were going to use this calculator in order to calculate the Shannon why no diversity index you see how painless that was I just went ahead and punched in my numbers and it gave me the number right there so this is really useful it's going to save you a lot of time so I hope that now you don't feel very scared about the Shannon miner diversity index it's a really excellent piece of work to use and it tells you what the diversity of your ecosystem is