hi and here is a quick tutorial about biodiversity and calculating the diversity of an area using Simpsons uh index now there's a couple different types of uh formulas to calculate so I'm going to push play on this tutorial slideshow and we'll get started all right so before we get into it what is diversity well if you go into an area and you see um a small area and you see just one or two spe PES in there obviously that means it has a low diversity however if you go into an area and you see many different kinds and here's the key many of each of those kinds of species um maybe 50 red ants 60 black ants 50 spiders 70 snakes sounds like Indiana Jones doesn't it a lot of each species that is what diversity is referring to so let's go through and and do a couple examples uh before I go any further let's just quickly point out that there are several different ways to calculate Simpsons index uh the IB in their syllabus for biology they'll put this uh equation here on the upper left and this shows simpsons's reciprocal index I personally prefer using simpsons's index of diversity on the upper right um because the result will give you an answer between uh zero and one which is a lot easier to make sense of in my opinion all right just do a quick Google search of the other um ultimately you are getting to uh the bigger the number the more diverse the lower the number the less diverse the both they're both similar in that sense now so D is diversity n let's quickly make sense of these variables n talks about the total number of species that you're sorry total number of everything that you will find in that area so those snake those spiders those red ants that I mentioned earlier you count everything that's your big n your little n lowercase n will refer to the number of each individual species so how many red ants that's one number that you'll keep how many black ends so that's another little n that you'll keep now let's go through and do a quick example so here's four three different quadrats a quadrant is just a square sample area so one is filling up with little alien faces um and then we have two others the right is filling up with a lot of different types of faces and the middle Square the middle quadrant is filling up with three different species so you have the red the purple and the yellow with the shades on three different species six of each of those species all right now let's go through and calculate one at a time and you might want to pause here and try to just get a guesstimate on what you think is the least diverse and which is the most diverse based on the big n and the little n that we have in our equation so let's move on here we'll calculate the uh one with all the alien faces first so just going through the equation you'll see that I have 36 alien faces and so 36 times itself another lowercase n so 36 time 36 minus one I'll explain the minus one in a second then we go to the next face and the next one there are two yellow faces so 2times itself 2 minus one and then we go to the next face the purple which is one 1 times itself minus one now you might look at that last uh part of the equation there and you might say well 1 * 1 - 1 which is 0 so 1 * 0 is 0 right perfect you're correct um this is why we see the minus1 in the original equation at the top the minus one is a bit of a fail safe to say that if we find just one species out there in a in a quadrant um we're assuming that that's uh random and it's won't count uh it's it's some somewhat of just an odity that came into our sample and is probably my migrating or moving through so we won't count it in this diversity sample and that's the way that we erase that one let's go through the math now U by the way the 39 was 39 total faces in there so 39 * 39 minus 1 we do the calculation and we end up with something like this and don't forget to do the one minus a lot of people forget that at the bottom we have to still have that one minus at the beginning of the equation and I end up with d equal 0.15 okay so what what does that tell me well that's actually a probability this is very low diversity by the way and probability says that if I were to pick two randomly out of this square and I picked any two well there would be a 15% chance that I would pick different ones okay sounds a little weird but think about it in terms of the lower the number the less diversity and that's because one of these species dominates you can see the alien phases really dominates and there's not a lot of anything else so that starts to maybe make sense let's go through one in the middle here now I'll go through the math we have six of each species and we have 18 total species so that's how we put it into our equation and we do the math and I just use some very simple calculator on the side of my computer here to do this this I hope I did it right we'll see maybe someone will comment if it's wrong and I end up with 0.71 which is 71% chance that if I were to pick any two of those it'd be different so that's pretty high diversity now let's go to the last one and here we go you can push pause and give this one a try if you'd like um I'll go through the math now and I found seven of one speci seven of another species six of another species six of another and three of those aliens um 29 total in there and I go through and I calculate that out and I subtract it from the original one and I end up with 82 that's very high that's a very high diversity so 82% chance that they would be different if I picked any two now what you could end up doing is you could actually start to draft these um maybe doing a transac away from Human Habitat and you lay down quadrats as you go down that Transit and you could see how the biodiversity changes as you move away from a human habitat that would be a nice uh very quick experiment you could do with really good results probably and just to finish we just quickly compare the different diversity uh indexes here indices here of these different examples and you see that zero is low one is high and maybe you can visualize what that might look like all right so we have a lot of different kinds and a lot of each kind in the highest number I hope that helps someone and send me a comment if you need any support with this hopefully I can help thanks