so some of these don't look anything like what you buy in the store and some of them look like crossed or earth stars stink corns candelabra shaped things right these are these are all mushrooms good evening i mean vonn step and i welcome you to tonight's contemporary science issues and innovations program our guest is david hit it professor of biology at clark university he's here to explain the wonders of the world of fungi especially mushrooms a subject that deserves much more attention fungi as were about to learn are extremely important in nature who knew this year as a grace fellow at radcliffe institute for advanced research dr hit it is writing a book on the subject for the general public but will have the opportunity tonight to become fungi literate ahead of time dr hit is a fellow and past president of the mycological society of mushrooms in general we think of going to the grocery store and getting mushrooms and it's part of a menu but they we understand have a much more important function in nature can you give us a little orientation like what are mushrooms and fungi and so on sure that's actually a fine question because i think everybody has an idea of what mushrooms are but they're actually not necessarily so easy to define so i'll put up this first image which will show you a group of organisms that i think everybody would recognize as mushrooms i have a cap and a stock and they kind of look like the thing that you would buy in the store as so everybody would call these mushrooms but these are also mushrooms so some of these don't look anything like what you buy in the store and some of them look like crossed or earth stars stink corns candelabra shaped things right these are these are all mushrooms this is also a mushroom this crust like thing that's on the underside of a log is a mushroom and the essential definition of what a mushroom is is that it's the reproductive  a fungus so it's not the entire organism ha it's just the part of the organism that is producing spores so we reduce the cap of that cap thing as the mushroom we know that has the spores but this has the spores yeah this is the this is the stuff yes this is producing spores as well so from my perspective it's a mushroom even though most people might not look at this and think that the word and the word mushroom might not come to me right mediately right this is this is also a mushroom this is a cup fungus and so this is also the reproductive structure of a do different group of mushroom aha so what i'm i'm trying to show you with this set of images is that mushrooms are tremendously variable in their form they don't all have a cap and gills and in my work one of the things that i've been particularly interested in is understanding how they change between these wildly different forms through evolution so the last slide i'll show you in this series is a pair of mushrooms that really don't look very much like each other at all what i want to shape like a candelabra one is more of a classic mushroom shape but these two are very closely related and we know that by comparing sequences of of certain genes that we use for doing systematic i see so one thing before you leave that is mushrooms are all says and just people out walking in the woods see the macroscopic reproductive structures produced by certain groups of fungi but there are many many fungi that don't produce macroscopic forms at all so  they're what we would call micro fungi they're very diverse very important and you never see them unless you're looking culturing them from soil or using some kind of technique that would let you see something very small ok so we have that then there are few other little distinctions there a televised still for instance which you know ordinary people like us go as toadstool has no formal scientific they use spores what's the difference spores are a hallmark of fungi yes so fungi reproduce by a spores they're mostly unicellular they can be produced sexually or asexually  and i have a series of images here that give you an idea of how a mushroom produces spores who can pick a mushroom in the field like this yeah bring it into your home or your lab and put the cap upside down on a piece of paper like that like that and make what's called a spore print so that a few hours later you have this collection of dust like material and those are the spores so the fungus is producing these spores for dispersal and for reproduction so these are the spores  fungus a mushroom this is a scanning electron micrograph a volt that produces tremendous numbers of spores asexually releases them into the air and that's why if you leave food out it it will get moldy so they function in a manner that's similar to seeds dispersal and reproduction but seeds are exclusively the production of seed bearing lamb plant yes and they're much more complicated structures so this is a picture of a hind seed and it's several it's well many thousands of cells in the center of this is a little plant embryo yeah it's surrounded by nutritive tissue and that's surrounded by a layer of protective tissue so it's much more complex structure than us then spores as one of the great innovations in the evolution of life and they serve a similar function the spores but they're not they're not the same thing right  in marine viable for a very very long time for most groups of fungi though we don't we don't know how long the last thing there's so much we don't know about fungi like how long how long the spores remain viable even though they have a very long evolutionary history people are working on this reason we don't know how long the spores that are in the soil remain viable yes ok and this is the sort of thing that can only be determined with experimentation i say ok all right so we now we have anyway spores and seeds spores would you say are more primitive than seats or they're just different algae in plants yet have structures that we call spores so there are there are plants that reproduce via not appropriate to say that spores are more primitive than seeds right ok they are what i wanted to know the the the fungi that produce spores are that exist around us today are equally as modern as any seed bearing that's a hard thing to determine as well because the fossil record of fungi although it's it's not absent it's it's thin compared to other organisms but we have we have some very old fossils of fungi and we also now have the ability to perform what are called molecular clock analyses where we use d n a sequence information to estimate how long ago a pair of organisms shared a common ancestor we have to calibrate the clocks with fossils so we're still dependent on the fossil record to some extent but we can estimate the age of fungi and although there's considerable ambiguity because the  methods have large errors associated with them we think fungi are at least seven hundred or eight hundred million years old so they're truly very ancient so they've been evolving alongside plants and animals as long as there have been plants and animals that takes this to the next thing which is they have an extremely important role in nature is that correct sure and i wonder if you could tell us about that fungi are absolutely central in the carbon cycle they fungi are like us they they can't do photosynthesis so they can't make their own food they can't make sugar from sunlight air and water lng plants can so they need to eat they need to they need to ingest organic compounds produced by other organisms and that's a characteristic that they share with us with animals fungi have a different mode of nutrition than animals they don't ingest their  food rather they absorb it from the environment but they nonetheless they are heterotrophic they have to consume organic compounds to get their nutrition they do that the source of all of those w have to get their nutrition from other organisms and those other organisms can be alive or dead if the organisms that they're feeding on are dead then those are the decompose or fall fungi the decay or and fungi are the master  this is a picture of some mushrooms that are leaf litter to carriers you can see these these are tiny little mushrooms but they're in the woods all over the place around here so how does look for them you'll see them and these are feeding on leaves small twigs etc which is actually very difficult material to digest so you and i can't digest that because we don't have we don't produce the enzymes that would make that possible so leaf litter to carriers are very important this is a wood decay fungus wood is a tremendously recalcitrant material it's very tough that's why we build houses and furniture out of it at last and yes it last but if your house if your house gets damp you know that you're going to have problems with rot and that rot is caused by fungi that have an symes that are that enable them to break down the plant material so these are the decomposer find they're tremendously important in recycling carbon and have the nutrients but then the beneficial symbiotes we call those mutual isms and in those cases we perceive that the fungus is providing some benefit to the living organism from which it's obtaining its nutrition insists like the another living source and the living source that is getting its carbon from is a tree lined tree on the left is providing sugars to the mushroom and the interface which is on the lower left there is you know the micro rise of which means fungus root so this is a fungus that is getting getting its nutrition from the plant and it's reciprocating by helping the plant acquire mineral nutrients from the soil and maybe water and other benefits so we perceive this to be a mutual isn't because there's mutual benefit but there's also conflict of interest here as well each one of these partners is trying to maximize its fitness at the expense of the other so  edibles as well as some poisonous things or they're very conspicuous but there's a much more widespread group of my cries of mutual isms which are called our bus killer mike arises and these are representatives of those kinds of fungi that don't produce a mushroom so these are spores of our bus killer micro rise of our bus killer micros all fungi on the screen here and you will never see a mushroom produced by these by these fungi but they form associations with we think roughly eighty percent of all land plants because they're tremendously diverse tremendously important in contemporary ecosystems and we also think there's a suggestion that's been made that these organisms and the symbiosis that they facilitate was was critical for letting lamb plants colonize the earth to move from aquatic systems on to the lessons that interesting now these are underground these are underground right so they're associated with plant roots the spores are produced underground there's no above ground structure at all they're all around us all the time they're tremendously important and you will never see them right and i just want to get this clear very very clear that the plants that they associate with they the plants depend on them for some kind of nutrients that they are vide the in the process the chemical  made of the body of a fungus is made of tiny filaments called hyphy they radiate out into the soil they have a very high surface area so they're very good at absorb we're being materials from the environment because that's what they do they have absor nutrition and so because they have this high surface area they amplify the surface area effectively of the plant roots and so they're able to absorb mineral nutrients from the soil that are limiting for the plant and and provide those to the plant and in return they're getting carbon hot carbohydrates plant i say so these are these are the happy symbiosis these you have a symbiosis where we perceive that there's mutual benefit yeah but there are also other where it's clearly antagonistic so there are many plant plant and animal pathogens so this is an example of a of a plant pathogenic fungus that's common around here it's called the cedar apple gal and in the spring time you will see these these gooey gelatinous structures formed on juniper trees around here so this is an example of one of the very many plant pathogenic fungi which are  carbon by digesting wood which as i said is a very heartening to do wood turns out to be a very loaded nitrogen environments and nitrogen is limiting for these fungi so if you look if you culture these things in the lab on special a they'll produce hifi these filaments on the auger plate and this fungus you can see here this is one of the fungal filaments one of the fungal hifi this is actually producing a little droplet and this is another example this is something called courtis up this is growing out of the body of an insect so this is the you could call this a mushroom i suppose it's the reproductive structure of the fungus growing out of the body of an insect that this is i n that background is an insect this is an insect here this is the i say up of an insect that was underground and if you're crawling on your hands and knees in the woods you might see these little orange this is on the very tip of of my jack knife  it's a carbon source or a fungus i already it waiting waited but i see dandruff and use infections are annoying but they're generally not very serious but there are fungi that are very serious pathogens for humans this is one called his still plasma that isn't inhaled and if it becomes systemic if it goes through your body it can kill you and there are a number of fungal diseases of humans that are relationship and their crucial importance in maintaining the balance in nature is that the way we should see them i think you should see them as being absolutely critical in a couple ways one is that they are  main mediator of the carbon cycle yes so fungi are are digesting carbon compounds and releasing carbon dioxide to the atmosphere so they're a critical link in in in the carbon cycle which as we all know is is very important because atmospheric balance of of c o two is so important to the wrath of the planet so they're important in the carbon cycle they're important as decomposers they release nutrients into the environment they make nutrients available to c fungi play very important roles in regulating the populations of other of our other organisms they have huge economic impacts we had a big gypsy moth outbreak this year yeah and one of the things that we were hoping for was that if there was a cool damp spring there's a fungus that can limit the populations of gypsy mobs oh for goodness and so that's just one small example of how fungi have very large ecological impacts right to i do when you have peculiar weather like the spring that's very hot or dry or something or other are there fun that then say attack a lot of trees fungi that can take advantage of that i do we see large scale destruction then i think the most famous example of that would be not with fungi but with a fungus like organism this is phytophthora infest downs which is the  late blight of potato and in the mid nineteenth century there was a period in ireland where you had several several particularly cool wet summers and that facilitated the spread of this fungus like organism we thought it was not i'm just like well it's it's it's filamentous it's a plant pathogen so in in those regards it looks like a fungus we call these things oh my seeds and the my seed part tells you that we used to think it was a fungus but that's the most famous example i think of a circumstance where environmental conditions had a very large impact on ultimately human economies because because of the growth of this this one fungus like or great right before we close up i'd like to ask at some point like how did you ever get into this think it's there or not a lot of people  fascinating well i am i went to u mass amherst as an undergraduate and i majored in botany and i took all the botanical courses i could including one mycology course and then when i went to graduate school i also was studying botany and i was in a in a program that had lots of different botanical subjects one of which was mycology and i just i had always been interested in fungi and even though i didn't go to graduate school for the purpose of study g enjoy i just sort of fell into it but i've always been interested in nature and and plants and plant like organisms algae fungi etc and so that's how that's  how i got into the head you would think this would be that it would spread the interested this and i hope spreads because it plays it's such a vital role and i guess one of the reasons why maybe people are getting more interested in is that there has been a lot of destruction of the soil often as a result of factory farming in the industrial type farming which is a really upsetting this soil and these things are essential to the health of the soil do you know anything do you think that that is true that that's going to be a problem i think with most fungi we don't we don't necessarily know what we've got there are about one hundred thirty five thousand describe species of fungi and that's a very large number yes but the actual number is a matter of of conjecture there was for a long time there was an estimate of one and a half million species more recently people are talking about five million species there was recently a very serious analysis published where somebody suggested that there could be one hundred sixty million species of fungi and so we we really have no idea what the diversity of fun i is on the planet particularly these micro fungi that don't make mushrooms so i think it's likely that there is massive extinction of fungi taking place i suspect that it's mostly due to habitat destruction and that sort of thing but most of the species that we're losing we assume that we assume we're losing have probably never been described at all and that's that's a great tragedy what it is but the gap between the described diversity of fungi and the estimated total diversity of hundred is so vast and it's one of the things that i think is really wonderful about being in my college together so many discoveries to be made yes so i think it's a very rich area i think there are lots of college and it's not it's not a huge professional area the mycological society of america the professional society i belong to has about a thousand members which is not that many it has six or seven writers just but i think the group  but there's a huge interest in my college among the public so there are lots of amateur mycologist snout who are getting interested their work with them i do i do it's of it's a wonderful group of people and here in massachusetts we're very fortunate to have the oldest mushroom club in the country is that the boston mycological club and the amateur mycology scene is really active there's a lot of really interesting people they're passionate about nature and i think that this is a group that needs lots of support from professionals like me and this is these are pictures here from a mushroom for a of the boston mycological club our local group that i'm involved with and they're tremendous fun and you can go out and see the huge diversity of fungi much more than you would see if you're just out walking in the woods by yourself this is the website the important role that these fungi play but anybody can check out and maybe go on one of these field trips in the cambridge massachusetts area massachusetts southern new england but there are there are clubs in new hampshire their cl there's a north american michael tical association that's the network an umbrella organization for all the regional clubs and the people that come to these for it is their very diverse in their backgrounds and their interests some people some people just want to collect information with us and we'll make sure that we you know we try to make this available to the public before we stop i'm fraid we're running out of time is there anything else that you'd like to cover  well one small pet peeve of mine when you go to restaurants and people and you see on the menu this is a this is a pet peeve that i and other mycologist share you'll frequently see items listed as containing wild mushrooms store and we grow them on compost this is she talking which is a wood to care we can grow it on logs are on sort of they deliberately grow absolutely ok so these are cultivated non wild mushrooms the wild mushrooms and because they're getting their sugars not don't label them as wild mushrooms because that the few mycologist that come to your restaurant will be will be very very yes ok that's great information and course when you write your book then we all i hope there will be a chapter about hibbett for joining us and giving us all this fabulous information tonight when you go i know you're writing your book this year are do you have any idea like when you will be publishing this so we can watch while i have a deadline that my my pub there are many excellent feel the gods will feel guys but they're getting better and they're getting better because we have this amateur community that is really quite sophisticated and they're demanding literature that describes the incredible diversity of mushrooms around so we know there's a we're sorry but also the role of pressure on this and i think what's what's missing is a book that is that in the book i am trying to  is just we don't see it we don't see it ever so we'll look forward to that book i hope you enjoy radcliffe this year very much i am we're delighted that you're of vailable and again thank you