hello again so now we're on to the third episode of the series what we're going to be looking at biodiversity and conservation so now that we've gotten a general idea of what a system is and specifically what a ecosystem is we're going to look at an important feature of ecosystems which is biodiversity so that will be our first task for today to define biodiversity we're then going to look at the origins of biodiversity so a little bit on evolution and natural selection and speciation we're gonna see why it's under threat and we're gonna also talk about way to consider conservation efforts and how that kind of ties in with some things we talked about in topic 1 about your environmental value system and the different ways to value resources so biodiversity is a broad umbrella concept really and it includes three sub components habitat diversity species diversity and genetic diversity and I've included this diagram here because really each kind of causes the next so habitat diversity is the range of different habitats that are available in an ecosystem for species to live in and you can imagine that the more habitats are available the more different the different species will be able to thrive there so because of habitat diversity we get species diversity and species diversity contrary to popular belief is not just the number of different species but also their relative abundance so their evenness and we'll get back to that in the next slide as well and species diversity leads to genetic diversity so the range of different genetic material that is present in a gene pool and again that makes sense because the more different organisms you have the more genes are going to be represented by them so you can see that biodiversity actually describes a range of different things the habitats the species and the genes so let's get back to those two components that I mentioned that make up the definition of species diversity and those are species richness the number of different species and even they are so if you look at the diagram on the right you can see that in the community one we have pretty much exactly even proportions of species between them so you've got 25% of a B C and D whereas community to one species is really dominant dominating in the ecosystem and that species a so eighty percent of the population is species a and you can possibly understand that a community one shows you a more stable ecosystem because the habitat is able to sustainably provide for four different species equally and it doesn't have one species that's so vastly dominating of the area as is the case in community too so it shows that the ecosystem is not able to support a wide variety of organisms so the next thing I want to bring your attention to are about our city hotspots and as the name would suggest these are areas with very very high biodiversity meaning they have a lot of different species which are relatively even and these areas are in need of emergency conservation not only because of their high biodiversity and in fact they are rich in many endemic plant and species that are found nowhere else on earth but also because of the demands that are put in these areas and we'll get back to that in the next slide but we can look at an example being tropical rainforests as his lovely picture below and chopped corn for us are believed to be the home of half of all species on earth so that really shows you how important they are for global biodiversity and how importantly being the home of so many different species biodiversity hotspots are under threat and a statistic to give you an idea of just how bad the threat is approximately a football pitch is lost every four seconds in the tropical rainforest and this is driven by timber demands by soy demands but recently conservation efforts have started to educate people on tropical rainforest value as a carbon store and again we'll get back to this concept of valuing resources and topics but another thing to consider you know ESS is a political subject is that many tropical rainforests and biodiversity hotspots in general are found in less economically developed countries than more economically developed countries or even newly industrialized countries and you met you may consider the fact that in these countries they have different priorities they're focused on development and may not be focused on kind of conserving biodiversity as much as an NEC that's already reached a stage of development so that is something to consider now that we're getting to the more applied versions more applied concepts in ESS so how does diversity exist what brought this around well of course evolution so evolution is the gradual change in the genetic character of a species through many generations and it is based on natural selection which is the fact that there is variation in a species and according to the environmental demands at a certain time some organisms will be better able to survive reproduce pass on their genes than others and the environmental challenges that they face really kind of distinguish the character at that particular time and fitness in this case is a measure of reproductive success and these are the four conditions that are required for evolution so variation as I mentioned that there needs to be different genetic character between the individuals the fact that there's competition so not all individuals will survive and in fact the more adapted the better kind of suit at the environment will be the one that can possibly produce pass on their offspring and overall be selected for in terms of their traits so this you can kind of imagine how this would bring about biodiversity because different species at different times are going to have to be adapted differently to the different environmental demands can process which brings about biodiversity is speciation and speciation is the formation of a new species when populations of the single species get separated in some way and they essentially happens evolved to different environmental demands which means that if they get reintroduced as you can see in the image in this slide they are so genetically different that they're no longer able to reproduce and no longer a species they have separated into two separate species and we can have several types of isolation geographical mechanical behavioral genetic the geographical can be caused by plate activities so movement of the major tectonic plates that are present on earth and the reason that this can either separate or bring together populations is because they can create mountain ranges rift valleys and these can also all isolate gene pools and cause speciation so this is another source of biodiversity now the idea we need to be aware that there have been five mass extinctions in the past all caused by a biotic factors and the evidence for this comes primarily from fossil records which show that successive layers contain different species and this shows us that some change has occurred now the types of extinction can be local where a species is no longer present in one area where it used to be ecological where there are so few members of the species left that it's no longer able to perform its natural ecological role or biological one is completely extinct and isn't found anywhere on earth now these fighting biotech extinctions caused in the past have been due to climatic conditions including ice ages tectonic plate movements volcanic eruptions and you can notice these are all abiotic so they're nonliving not human caused but right now we are experiencing the first-ever biotic mass extinction which is caused by just one species humans the main driving factors are hunt over hunting destruction of habitats including deforestation and the introduction of exotic species which can completely destabilize an ecosystem so below are just five examples of species that have been have gone extinct because of human activity and that brings me to the factors that can make a species more prone to extinction and these are quite intuitive but they are being a smaller size population OUP's populations which are specialists so only a specific type of food like pandas which only eucalyptus the quality of habitat if it's polluted they're less likely to survive large mammals which are a source of meat and therefore targeted by poachers out eristic species who tend to stick together and tend to come to each other's aid when they're being attacked poor competitors so species who evolved without predators and don't have those kind of pre adaptive instincts to kind of fight and also the level of charisma is an interesting one that connects me to my next point which is that Tigers for example which are kind of appealing to the public they look cute for lack of a better word they're more likely to attract funding and attention compared to for example lichen who are equally as important but don't have the same level of charisma and the tiger and when we're talking about conservation efforts and specifically in terms of biodiversity and in general this ties in to what we talked about in topic 1 which are environmental value systems and the way that you apply value to a resource now this image below is really great and I recommend you guys to kind of study it but they show you how as you move from direct use values something that is tangible like food or biomass that you can directly retrieve from an environment it's much easier to quantify and assign an economic value to something like existence value so the the right of a species to exist in and of itself the so the fact that you wouldn't want a species to go endangered or request values so the value for future generations and you can base arguments on conservation of biodiversity on several domains from aesthetic ecological so you know a carbon cycle the nitrogen cycle economic ethical and the social justifications as well so that's all I have to tell you guys about in terms of topic three as always make sure to check out our website to find out how you can knit get some tutoring from us but other than that I will see you in topic four