good afternoon and welcome again to this afternoon's presentation botanical science for beginners thanks for joining us early we've watched you all kind of come in come in the door here and there and thank you for taking some time to sit down with us on an afternoon we can all feel that the weather is getting nicer and all the more reason to go outside and study plants we have a little bit more inspiration to spend some time outside looking closely at things um so thank you for giving up part of this afternoon to join us here for botanical science for beginners i'm james stevenson i'm with the university of florida ifas the institute of food and agricultural sciences we serve our community pinellas county as a resource for research-based information on particular topics of interest and of necessity so you can come to us for free information non-biased uh tested researched all these great things we're a local resource just for you and today our foray will be botany now we're a small but powerful crowd today and therefore i'm gonna go ahead and encourage you now as we go please use the q a to submit any questions you might have or any complaints or any contradictions or anything you'd like i should be able to get to all the q and a's as we go so we'll cover a lot of territory but we'll do this at your pace studying botany or just bringing up the subject of botany uh might be a bit intimidating it is of course one of the sciences one of the biological sciences a course of study um it's possible that people might have had a bad experience studying botany at university or even in high school once you get into the terrifying terrifyingly complex process of photosynthesis and the chemical and the electron transfers and all those things can turn people off and we even have changed the name of this presentation to include the words for beginners our first outing of this presentation was just called biological uh botanical science or you know botany 101 and we wouldn't get anyone to sign up and it's probably because there's this fear factor look at what the oxford dictionary of biology has to say about what botany is it's all these scary words uh anatomy morphology physiology biochemistry taxonomy cytology all these it's okay because today let's redefine that botany a little bit let's take a breath and look at some really cool things about plants they're all around us they're easy to study because they don't run away they can be very fascinating it's a net the plant world is an endless encyclopedia of fantastic things and our lives are intrinsically woven into the botanical world that surrounds us so let's take a step back and see what the plant world has to offer to us now again there's around 400 000 different plants writ large plants writ large there's 400 000 different ones and a humongous variety so how on earth if you're interested in studying plants how in the world do you start with all that diversity with all that variety how am i ever going to make sense of an individual plant and learn anything at all about it well we're going to help you with that now plants exist in all the environments we've got our rain forest with all of its rich diversity and plants are adapted to these almost perfect conditions for plant growth but plants have obviously to all the environments that exist and we even have these vast expanses of coniferous forest that can withstand being completely ice bound for three four months out of the year and they do just fine here in central florida we have our own diversity we have our own forests we have our own plant communities that are perfectly adapted to the natural environments that are created by the non-living components of of our world the weather and the soil and our latitude and all these things that come together to create the conditions that are then favored by the particular plants that have taken up residence there so here's a picture of some of our um oak forest here at brooker creek preserve with the live oak canopy and the palmetto understory but we also have pine flatwood see these ecosystems are named after the plants that are there the oak hammock the pine flatwood the hardwood swamp so here we have a flooded forest and these plants are adapted they didn't just find themselves here and say heck would it all grow here these are plants with adaptations to living in a seasonally flooded forest you can even see in the background the trunks of the trees are swollen at the base to give them a little bit of a little bit of balance a wider a wider stance if you will to give them a little bit better purchase on a saturated soil here at brooker creek preserve we have those upland and fresh water wetland systems this is an aerial shot of our sister preserve whedon island and here the plant community is completely different this is mangrove swamp and so the plants that are living and thriving and perfectly adapted to living in a mangrove swamp are of course adapted to saline conditions um they can ex they can exclude salt from entering their tissues or they can take the salt in and squirt it back out all kind of fantastic adaptations to living in saline conditions so again we'll go back to a terrifying definition of what we're talking about plants any of a kingdom of multicellular multicellular eukaryotic photosynthetic lacking locomotive and blah blah blah let's reword that we're talking about living things multicellular that have the magic power of taking sunlight and atmospheric carbon dioxide and water knocking all these things together to produce sugar and oxygen as a byproduct which is pretty cool in my book making them the center of a food web the bottom of a food chain however you want to look at this plants are the producers they take invisible substances and make them into three-dimensional objects including their own cells they can make from air and water and sunlight they can make physical structures three dimensional objects not fungus fungus is the wrong branch of the tree of life plants branched off a long time ago and as everything kind of adapted and made use of the world the animals and the fungus kind of developed along the same branch so we've got the animals and the fungus on one branch plants on another branch so we got no fungus for you today that's a separate lecture for a different day back to plants what we're going to look at today we're going to explore what are we going to do with these 400 000 different kinds of plants how are we going to break that 400 000 number down into nice discrete more easily understood groupings of plants and then once we've looked at the big four we'll find out what those big four have in common what was it about that first organism that had all the characteristics that make a plant a plant what was what were those characteristics of the original plant that eventually diversified into into what we knew today and then we'll end up with just a taste of the fascinating world of plant hormones believe it or not there are plant hormones basically answering the question how does something that can't run away react to the environment if it doesn't move it can't run off it can't go into a shell uh it can't put a plaster on a wound how do how do these um beings react to the environment and that can often be done through hormones so we'll finish up with that so what are we going to do with these 400 000 well we're going to classify them we're going to put them into nice easily studied discrete bundles and it's what humans do we do this with everything we sort things out we put like with like and putting like with like can be a subjective exercise to you you might sort things by color someone else might sort things by size someone else might sort things by what they're useful for and those are perfectly acceptable ways of organizing information organizing organisms anything like that and so we've classified plants and we've put them into useful bundles like trees someone who studies trees is going to want to have that circumscription of the plant kingdom carved out for them or they will carve it out for themselves right vegetables are an important group of plants they're economically important they're nutritionally important so that's a nice little collection a nice little bag full of plants the vegetables other economically important groups of plants might be invasive plants because they take a lot of money to get rid of right that's economically important you pay someone and you use products that cost money to deal with invasive plants like weeds um you know invasive plants are kind of like weeds on a bigger scale and of course just ornamental horticulture an important economically important circumscription of plants we put flowers in our garden and like i said these are perfectly acceptable circumscriptions but they're not scientific and of the 400 000 different plants in the world you would probably have that many different opinions about where to put an individual plant in a set of group in a set of bundles like illustrated here so the scientists through studying evolutionary biology have made some pretty tried and true divisions of plants we have for our intents and purposes only for and i am sure that all of you can remember by the end because i'm going to repeat this about 100 times maybe 400 000 times the four big groups so when you look out the window you don't even have to go outside it might it might have gotten a little bit warmer from the comfort of your home you can look out the window and you can break every single plant out there into one of four groups and from there you can go on to learn more about that group and eventually that individual plan the four big groups are the mosses the ferns the gymnosperms and the flowering plants these are scientific categorizations the mosses represent modern species of some of the very first land plants they have a very simple structure they don't have any plumbing they don't have any vascular tissue vascular and plumbing are the same thing so they have no roots or stems or leaves because those tissues require the requisite plumbing the mosses are just sitting on the ground low to the ground where osmosis can provide the water to go through their short little squatty bodies um and they reproduce by specialized cells single cells that they release and hope against hope that that cell that they send into the environment will germinate and grow into the next generation those are the mosses that's what defines moss moving up in a little bit of complexity we have the ferns that have true roots stems leaves but they've hung on to that very ancient way of sending one cell into the world at a time hoping that that one cell will grow into an adult eventually becoming more specialized especially in the reproductive process and not leaving quite so much to chance we have the gymnosperms they do have vascular systems like the ferns root stems leaves but they've got this wonderful invention the seed where an embryo is encased in a nice nutritious coating and then that whole thing that young plant is sent out into the world to grow into the adult and the ultimate in sophistication if you will the flowering plants where all these processes the reproductive process results in the seed but the seed is encased in a structure called a fruit and that fruit in all its permutations is the perfect vessel for getting offspring away into the world to find their fame and fortune but they've got everything they need they've got some food to take with them they've got a mechanism to get them very far away from the parent plant so there won't be any competition so the flowering plants are kind of the apex of plant evolution nothing against these quote-unquote lower plants the system worked millions of years ago it's still working today we still have mosses we still have ferns we still have gymnosperms and so on so taking a closer look at these mosses now there are some things that you may have heard referred to moss moss is a word that is in the vernacular we talk about moss growing on things you know normal people even talk about mosses growing here and there but there's a lit there might be a little bit of confusion and application of the word moss as it applies scientifically now remember scientifically these a true moss is a plant with no root stems leaves and reproduces by spores the stuff hanging in the trees that's referred to as hanging in the trees that gray stuff hanging in the trees is not moss it's a flowering plant it's at the far other end true mosses remember have no vascular tissue they reproduce by spores they have to be very low growing or they have to grow relatively close to the surface where they're attached because they depend on that layer of water to get the to get there to get to have access to the water that they need uh and to move their bits around that they need i'll show you about that a little bit later but this would be a nice example of a mossy habitat it's damp it's cool it's humid it's kind of shady there's not a lot of worry about these tiny little plants drying out but you have to hand it to these little things i mean here's moss for scale this is what we're talking about these itty-bitty little individual plants that form these colonies they still do that much better at not drying out than aquatic plants do so the mosses represent the plants that came out of the water and managed to avoid becoming desiccated they don't have breed stems or leaves but they do have a little bit of waterproofing so they can survive on land and they took advantage of the fact that nothing else had crawled out yet and the mosses set the stage and they grew where they could and they reproduced where they could and the system worked because they're still around today still very small because of that lack of vascular tissue they can't move water over great distances so they stay very small here's a pine needle for scale and these plants are producing their reproductive structures a long stalk with a little knob little bulb on the end and that bulb at the tip so all these structures are growing out of an individual moss plant and at the tip we have this capsule that contains the spores and spores are specialized cells individual cells that this plant that produced this structure is going to toss out a couple dozen of these spores hoping against hope that one of these it's only one cell so it's going to drift in the wind hoping that at least one is going to land somewhere where the conditions are just perfect for it to germinate and grow the moss life cycle you've got here's that capsule a little cap comes off and a little lid comes off it's quite a complex little system that capsule and the spores kind of shake out like a salt shaker pepper shaker again it's just one cell and they drift somewhere and one spore is going to grow into this plant by cellular division and this plant these are not true leaves remember these are just scales but it's photosynthetic this little single plant here that grew from a spore is what's referred to as female at the tip of this plant there are some specialized cells that enclose the most important plant cell ever the egg cell another spore is going to grow into you guessed it a male plant that plant produces a capsule full of sperm cells and with conditions being just perfect with a layer of water washing over the surface of these adult plants once the spores have matured a layer of water is going to wash over the surface of these adult plants the sperm is released into the water and is going to swim and find its way down the neck of this structure which happens to be called an archegonium but you don't need to know that the sperm is going to find the egg cell we all know what happens when sperm meets egg you end up with botanically or early developmental biology you end up with a zygote that becomes the embryo that is then going to grow into an adult the adult in this case is represented by the stalk and the capsule so literally we have two different plants in one we have the plant that grew from a spore right this is a plant that grew from a spore the plant the plants that grow from spores produce sperm cells or egg cells and the egg cell then develops into another plant an embryo of another plant the sporophyte the adult that's going to then grow up looking very different and still attached still attached it's going to grow up into being just just a stalk and just a capsule to reproduce this whole thing and that is this bizarre alternation of generations we'll see it again in the ferns but we can forget the mosses for now that's it that's all that's really all you need to know they're non-vascular that's as big as they're gonna get they represent an ancient way of life that has survived to today and they are one of four groups of plants today moving up in complexity we have the ferns and i bet a lot of you could identify ferns i bet a lot of you have grown ferns a bit of a lot of i bet a lot of you are growing friends unintentionally because we have quite a few native ferns that come up where you least expect them and we even have some non-native exotic and invasive ferns whose success at reproduction in this part of florida has meant that they kind of come up everywhere quite on their own technically speaking all the ferns which is a scientific grouping of plants they do have vascular systems so they do have real roots they have real stems and they have real leaves but they've hung on to that weird reproductive method of using a single cell throwing a single cell out into the environment that single cell developing into a separate plant that then forms an embryo the embryo becoming the adult plant now this is the underside of a golden polypoty or golden foot polypotie golden because of the color of the scales on the stem also golden because of the color of these structures underneath the leaf and many folks know that if you turn a fern leaf often referred to as a frond if you take a fern leaf and flip it over you might often see this pattern on the reverse and many people would say those you know stan holding it at maybe books length saying those are the spores which is technically not wrong but i'm going to teach you what's even more right so we're looking at the underside of this fern frond right these are not bugs these are not insects this is not a disease this is the fern undergoing its reproductive process so on the underside of the fern leaf we have these crazy dots so the ferns have evolved leaves and they have put their reproductive structures on their leaves and ferns could look very ferny or they could look like this uh this is an adder's tongue fern not looking as ferny as the others with just the one kind of paddle shaped leaf here and then another leaf that's more modified to have those reproductive structures on more diversity in ferns the bird's nest fern probably not what you would draw if you were asked to draw a fern but because it has vascular tissue it has real roots stems leaves and reproduces by spores that informs the scientific community that this individual organism belongs within the group of plants that are known as ferns you might grow the staghorn fern this is another plant that has modified leaves in this case modified for life attached to the trunk of a tree with one set of leaves that are flat and adhesive they can actually adhere to the trunk of a tree and then they have the other leaves that kind of stick out into the air and and those leaves are the ones that release the spores those crazy single cells that are going to grow into another plant so we have sterile and fertile leaves on this fern but going back to our original our golden polypoty looking a little bit more fern-like than the previous examples that is not a spore it is a reproductive structure and it does have something to do with spores but let's zoom in on this one structure that's being circled here what we see if we zoom in on that is a little island on the back side of a leaf and each island is made up of these spherical structures with a zipper so you can see the structure that's being circled here is repeated over and over and over again excuse me you can even see if you look down some kind of unripened structures that have yet to develop and turn brown and unzip these structures are called sporangia like gymnasia sporangia it's where the spores come from it's the housing for the spores so the spores are actually inside the sporangia as far as remember they're just one cell so on the back of this fern frond we have this dot if we zoom in on the dot you can see that it's a cluster of these smaller structures called sporangia and if we take one sporangium here's a side view of that one sporangium with the zipper just along here you can now see the individual spores inside that structure so incredibly small spores are incredibly small microscopic they're one single specialized cell and depending on the species depending on the group you know even within the ferns you can break them down into nice discreet bundles they're all still ferns but some are more related to themselves than others inside that sporangia there might be 24 or 36 consistently inside one sporangium there could be 24 or 36 individual spores so when conditions are right the sporangium singular will open that zipper will kind of unzip it doesn't really unzip it kind of pops open it's kind of a um an explosive event there's two of these cells side by side maybe this one and this one that are very weakly linked together and they'll actually release and this part is under a little bit of tension so it pulls the sporangium open releasing the spores inside and things get really weird once the spores are released you can watch this happen you can take a 10x magnifying glass up to a fern frond shine a bright light on it so you can see what you're doing and the bright light is going to dry things out a little bit and you can watch these little things just poop pop open and cough out the spores so here we have a drawing of one of those spores being released i don't think it actually does a corkscrew spin but i thought that was quite fun as an illustration let's assume that it does it gets caught in a little eddy of breeze and gets flown over there that spore just like our moss spores is going to germinate and grow and divide it's a single cell so it's going to begin to divide divide divide and it becomes um exponentially larger and larger and the cells differentiate and they form their own plant so the spore lands germinates divides differentiates into a separate plant a little heart-shaped plant and that heart-shaped plant contains the same the analogous structures to the moss they have the little sperm-bearing structures and little egg-bearing structures and with water and thyme the sperm is going to swim over to the egg bearing structure and literally swim they have little tails they're going to swim down the archegonium and find that egg cell and fertilize the egg cell resulting in remember a zygote embryo brand new plant brand new embryo union of egg and cell is a new individual right this new individual then grows and becomes the adult that we can see most of this other stuff happens out of sight on a very small scale but then we get the grown-up fern produces the sporangia on the underside of the leaf sporangia ripen release the spores and there we go again it's called an alternation of generations there's two generations there's the spore producing generation that we can see and then there's this this gamete the egg and sperm plant so two different plants and here's that gametophyte this is what spores grow into spores don't grow into ferns spores grow into these things these things these prophali these gametophytes they produce eggs and sperms and once the eggs and sperms get together that embryo grows in to the fern you can see these you can find these uh they like well wherever you see a fern growing this probably happened so it's not a hundred percent by chance right it actually is effective and efficient and it does work but of course boars need to be produced by the billions for one to reach maturity you can actually grow profally if you can collect the spores off a mature plant and put them in some damp soil people keep a lid on it so it's nice and humid eventually the little gametophytes are gonna grow and if a sperm meets an egg in the archegonium of this gametophyte that embryo will then begin to grow out of the gametophyte and here comes the next sporophyte generation those are the ferns that's how the ferns work pretty crazy i know is everyone all right i'm going to insist that we all take a little two-minute break look away from the screen look down think about a question put your question in q a get a drink of water hold on there we'll take two minutes for a little bit of a breather and process what we just thought about how about that and i'll have a look at the q and a angela got in very early what's a good place locally to study plants excellent question and is there an app that i recommend for identifying plants plants because they don't run away you can study them anywhere they grow any park or parking lot always consider botanic botanical gardens you've got the opportunity at botanical gardens to have plants labeled and you can get a lot of information about the label its common name its scientific name which can be very descriptive what family of plants it belongs to is often there if you're interested in cultivating plants sometimes the cultivate the cultivation notes are included on the label so botanic gardens there's one at the university of south florida there's a botanical garden in largo but otherwise a good field guide and a and a public park are good places to go as long as you remember the rules that you don't collect things you don't pick things unless you've got permission that sort of thing and as far as an up an app um i naturalist uh we'll put perhaps we could put a link to i naturalist there are a lot of plant identification apps and services but we prefer inaturalist because inaturalist is citizen science by using the app you add to the knowledge that that application contains you can you make a contribution and i naturalist doesn't just give you a suggestion it gives you a suggestion and then you need to double check and if you make a claim like i saw a ivory billed woodpecker and you put your picture up because that's what was suggested you'll have 10 people come in [Music] who's gonna they're going to see that post and they're going to say actually what you saw was and you'll you'll get agreement you'll get consensus of what it actually was and by being incorrect in your assessment you nonetheless have um contributed to the scientific discourse and you've added a photograph of an individual organism that was then identified by experts as what it's claimed to be so i naturalist is the one that we use uh now how many sporangia in one of those things let's see if we can back up i don't sure do i still have controls an excellent question we're sitting here looking at this spot on the back of a fern frond it actually the spot has a name it's called a saurus s-o-r-u-s [Music] a collection of these things are called sore eye and how many sporangia are going to be found in one particular spot it could depend on the species or it could be indeterminate this particular source that we've zoomed in on here is continually producing these sporangia and it could feasibly continue producing sporangia until the leaf is severed from the plant so it could be a finite number it could be an indefinite number just based on the amount of time that the plant is going to live that could be a distinguishing characteristic for a particular species there it's very likely that some ferns only produce x number and no more so i'm sorry there's not an easy answer to your question it could be it could be some it could be all many infinite i hope that's a good enough answer wendy thank you for the question um rebecca has an interesting question rebecca actually brings up a little bit of a fib that i've been kind of stitching through this presentation that there's only four different kinds of plants there's more there are nuances but for those of us who just want to leisurely study the plant world there's basically these four now there's another group that are called the liverworts and the lycophytes there's others but they're kind of at the tail end of their experiment of living on earth whereas these four that we're studying today have become dominant today there are other groups that have been experimenting and are kind of fizzling out including some plants that are called liverworts and they are very similar they look very similar to this gametophyte this fern gametophyte and how would you tell that how would you know well the gametophytes the fern gametophytes are individuals whereas the liverworts are branching plants so you would see a structure like this looking very similar constructed very similarly but it would be continually growing the gametophyte is a finite individual plant it gets to be a certain size and it stops growing whereas the liver wart continues to grow so you would you would find great mats of liver wart whereas you would find individual gametophytes here and there jay wants to know if plants sleep at night and it photosynthesis does photosynthesis stop at night two excellent questions um photosynthesis does not stop at night um some plants actually will wait until nighttime desert plants in particular but not exclusively wait until night time to open open their doors to the air they don't even you know how plants take in carbon dioxide we'll get to that later desert plants they don't want to open the doors because they're going to dehydrate so they wait until the sun goes down to open their doors and that's when they collect up their carbon dioxide from the atmosphere so they have to perform certain functions overnight so they can close shock up during the day i hope sylvia's comment that the process is so complicated i hope we're explaining it uh even though it's complicated i hope that we're getting some clarity for you and thanks for joining us all right hope we all got a drink got to stretch your eyes we'll carry on and we'll move on to number three the gymnosperms the conifers they're often referred to roots stems leaves and they've got this wonderful invitation invitation they've got this wonderful invention the seed so we're gonna leave the chance of spores behind and make an investment into the next generation by sending an embryo into the world almost fully formed with a little bit with a lunchbox to take with it away from the parent plants for lack of competition and hopes for the best the gymnosperms so these arrived on scene and their efficiency and their ability to get very tall gave them an extra presence on land so we had the mosses kind of setting the stage and then the ferns came in and they started getting better at things and they were looking out for themselves and then along come the conifers and they figured out wood and trunks and bark so they got big and everything changed forests of conifers coniferous forests became dominant land vegetation but not all gymnosperms are conifers the biggest living thing ever in the history of anything is was a conifer like giant redwood is a conifer right it's a gymnosperm look it's even bigger than a mountain they're huge um but there are weird remnant conifer experiments i mean conifers differentiated experimented we have conifers out in the deserts of namibia that are basically just two long leaves that get longer and longer like your hair when if you have it longer and longer and the desert winds break the ends off and they just keep growing longer and occasionally they'll produce these cones hoping against hope that someday there will be conditions that will be right for the seeds that are the seeds that are contained within these cones to grow into another one of these weird things this is well wichia conifers are also represented by the cycads cycads are an old old old experiment in um land plants a lot of people think these are palms because they have the trunk and the crown but they're not they're conifers they're ancient these are known in the fossil record um a lot of cycads are still um dependent on insects for pollination because you know insects were around when conifers first arrived and they tried to form um some sort of agreement the insects and the conifers but didn't really didn't really work out so the conifers kind of stuck with being wind pollinated um and the insects eventually had a much better relationship with the flowering plants once they arrived but a lot of cycads still need some insects they need some of those early evolving insects like beetles that are still around and have been around to visit their male and female cones the cone the female cones of course being the the structures that that produce these wonderful things called seeds most of us know conifers and evergreens um from the more familial familiar temperate landscape conifers or landscape evergreens they're often called the christmas trees right so we know them we know they're represented but let's take a look at how they work i mean we we peaked under the skirt of the mosses and the fern so let's just see what's going on with these gymnosperms they're conif they they produce these structures called cones or strobili strobe meaning a repeating pattern and we've given again male and female to the two different um gametophyte types so we have what are referred to as the male cones and the female cones the male cones of course being where pollen is produced so a pollen grain is kind of all that's left of that gametophyte that was a separate plant in the mosses and was a separate plant in the ferns that's all been um simple not simplified but streamlined specialized and now the gametophyte is just represented by the little pollen grain contained within a nail cone now you might have seen these they're temporary the male cones are temporary they have one job to do produce pollen release it okay that's two jobs produce pollen and release it and then they're done they're dropped off the tree they're not green they don't photosynthesize they're empty of pollen they're just jettisoned and you can see these are the male cones their job is done so they fall into the ground you can see where this the individual scales of the cone have broken off here so you can actually see these scales let's zoom in on one of these scales here's one of those scales in cross section and what it's full of are the pollen grains all that's left of a entire gametophyte in one special pollen grain with a couple of nucleus it's like one cell with several nucleus nuclei and two wings there's a wing there there's a wing there here here's that cell that's full of nuclei the wings are to get airborne so when the pollen is ripened the male cone each one of these little scales is going to open up and release all these guys out into the world we all know what happens next when the conifers are releasing their pollen it goes everywhere the wind is the pollinator the wind takes the pollen from the male cones into the breeze and over to another tree of the same species which is producing the female cones and the female cones are small and sticky sticky because they have to grab pollen out of the air they even have special little droplets of sap that can get can get covered in um covered in pollen they're very sticky little sticky um sap droplets that they can then suck back in pulling the pollen inside the cone once inside the cone the female cone let's back up so here we have the female cone and we're going to look at each one of these scales and each one of these scales contains an egg an egg cell within this structure way down in here so the pollen is going to land whoops the pollen is going to land and it's going to grow down this hollow tube and it's going to grow through all this tissue until it finds the one special egg cell to fertilize to grow into the embryo and for three years that female cone is going to sit developing that embryo and that seed providing that embryo and that seed with nutrition get the embryo nice and well developed get the seed nice and full of carbohydrates for the road it's gonna differentiate some cells into a long wing and eventually from each one of the scales of the female pine cone after three years the scales are going to peel back and the seeds are going to slip off the seeds are going to slip off and they'll fly away they're naked they're just seeds these are seeds that have been like they're these are seeds with a piece of what is that not fiber what am i trying to say fill uh tissue i don't know wings stuck to the seed the the dispersal mechanism is the wind just like with the pollen forget the insects forget the animals let's just send the children off on little whirly gigs that's the conifers seed lands grows seed germinates the embryo the fully formed embryo the baby tree is inside the seed and if that seed lands someplace good it's going to germinate and here comes a new tree it's not a different plant like we had in the mosses and the ferns what the seed germinates into is going to be just a baby version of the plant that released the seeds and the circles unbroken i'm gonna let y'all go again let's take another two minutes for a bio break i imagine we've been at this for an hour we should be at the half hour mark so i imagine we need to stand up again so again okay stop talking let the people go for one oh [Music] all right time's up we're halfway there hope everyone's doing okay we'll pick it up and move on to the big one the major of the 400 000 different kinds of plants that have been described out there about 300 000 of them are flowering plants so you can look out your window you can rule out mosses because you probably can't see them from your window you can rule out ferns if you're not obviously looking at a fern you are probably fully aware of the two or three or four different native species of of conifer of genus sperm and a couple others like kunti a popular native plant everything else is a flowering plant believe it or not the oak trees the grasses the palms everything the the weeds the forbs the spanish moss flowering plants and the majority of the plants that we have are the flowering plants the magic of flowering plants is that they put their seeds inside of a fruit yes all flowering plants produce fruit fruit botanically speaking not nutritionally speaking not cookbook speaking botanically speaking fruit is the ripened ovary of a flowering plant containing fertilized eggs which are the seeds remember when our egg cell got fertilized on the cone we're still fertilizing eggs we're still making seeds but in flowering plants we're putting those seeds inside of a fruit whether you can eat it or not doesn't matter it's called a fruit a ripened ovary is called a fruit and that fruit facilitates the dispersal of that seed remember how the conifers depend on the wind the flowering plants have been around more or less alongside the animals and so many flowering plants have kind of engaged the animals as a means of dispersing their seeds by way of fruit but there's some there's some tricks there's some tricks with fries so a very basic flowering plant land uh layout a very basic flowering plant blueprint would be petals stamens pistol the petals attract the pollinator here comes the pollinator the pollinator is there for the nectar the reward so the flower has to have petals to attract the pollinator nectar it has to produce the sugar water that does no benefit to the plant whatsoever it has to produce this sugar water this nectar as a reward to entice this insect to come to the flower once the insect in this case to be is at the flower taking that nectar reward the plant is going to sneak or force or hide pollen onto that insect so that when that insect then goes to another flower looking for a new reward the pollen is going to be transferred so it's a little bit of trickery and it can get quite insidious there are a lot of tricks that plants play on their pollinators and there are a lot of insects that outwit the plants tricks and can actually outwit the system sneak around the back side of the flower steal the nectar not get covered in that dirty pollen it's all going on out there but basically speaking here we have a pretty typical flower layout you have the petals that are attracting the pollinator the pollen in between the pollinator and the reward so the pollinator has to get covered in the stuff from the payoff the pollinator gets the nectar reward the plant then forces the insect to transfer that pollen when it visits a flower of the same species this is how the flowering plants flowers are put together this is basics this is basic flower anatomy a side view where you've got the little modified leaves that form the flower bud once the flower is ready the bud peels back the petals this next layer also peel back the little pollen bearing structures are then exposed to the environment and pollinators and the most essential part in the middle this organ called the pistol and the pistol includes an organ called an ovary and that might be familiar to you with the eggs inside the ovary basic flower structure now those parts those basic flower parts that are the same across all flowering plants can be different shapes and sizes a myriad a world of different shapes and sizes but they're the same parts in the same order here we have the flower of one of our native bromeliads and we have the petals not flared open but rather conformed configured into a tubular structure and the stamens are all the polybearing structures are all crowded together this is to facilitate pollination by a long beaked nectar customer so the nectar customer in this case would be a hummingbird and the hummingbird has to get past the pollen bearing structures to get to the nectar so the plant just covers its little hummingbird head with palm so that when this bird goes to another matching flower it's going to transfer that pollen so it's the same structures it's the same idea but flowers have diversified into this fantastic myriad of shapes and configurations to facilitate their own pollination needs some flowering plants don't make petals some don't want to put the investment into petals and nectar and all that nonsense when wind works just fine for the conifers why can't it work for these flowering plants we all know the oaks are quite good at putting their pollen into the air they do it every spring and the male flowers the flowers that bear the male structures the the pollen bearing structures just like the conifers these flowers fall off the female oak flowers of course with no petals no nectar because they've caught pollen out of the air they're still flowers they've caught pollen out of the air just like their ancestors um they pull pollen out of the air and that ovary that special floral organ the ovary hangs out on the tree and develops into the fruit of an oak tree remember i said botanically it's fruit whether you can eat it or not it's a ripened ovary it's fruit if it's going to kill you it's still fruit it's in ripened ovary with one or more seeds inside technically it's fruit we might all have seen this literally the birds and bees where we have a bird or a bee pollinating the flower the bits that aren't needed fall off the petals don't need them anymore they've attracted the pollinator pollination has happened the male the anthers the the pollen bearing structures they've done their thing they can go not supporting them anymore but the ovary stays the ovary stays attached to the plant and grows and grows and grows c into a fruit you can even still you can identify different floral structures on a ripened fruit in the case of a tomato it still has the little specialized leaves that form the bud there's they stay around and you can see the little structure this little stigma and style where the pollen is received it often is still stuck to the overly engorged and swollen ovary that contains the seeds that will be the next generation peanuts they've got seeds inside they're a fruit this is science this is not a cooking class this is a ripened ovary with fertilized eggs which have developed into seeds ripened ovary with seeds inside equals fruit peanuts are fruit so the moss is the ferns the gymnosperms the flowering plants see how easy that is see all the botany that you already knew so let's take all these groups backwards where did they come from what made plants plants where did this all start well what they have in common are their plant cells featuring this special thing called a cell wall really special thing called chloroplast and an area of um it's called a vacuole although it's not empty but it's a an area within the cell whose size and shape can change called a vacuole but the cell wall is made of a very very very special carbohydrate they're called cells and animal cells are called cells as well the the term cell as it is applied to living organism tissues tissues being made of cells cell was applied to these structures because of someone looking at plant cells under the microscope they looked under a microscope at plant tissue and they saw something like this and they thought to themselves those look like the cells that nuns live in i'm going to call them cells and that's how we get the word cell as it applies biologically named after the chambers that for some reason people thought they needed to live in to be super religious cells the plant cell wall is made of cellulose a very complex polysaccharide carbohydrate that has some fantastic properties cellulose is tough it's waterproof it's what gives plants their stature it allows them to grow upright and present their solar collectors to the sun cellulose is also present in the dispersal mechanism for cotton the the fibers of cellulose help disperse the cotton seeds and of course we've taken advantage of that cotton is not the only cellulosic fiber that we've taken advantage of cellulose led us to papyrus which led us to paper which led us to books and the printing press made us smart plants made us smart if it weren't for cellulose we wouldn't be the smart it worked for plants right the central vacuole is this empty space where water can be shunted in times of plenty and stored making the plant a nice turgid plant making the cells very turgid making everything very taut and upright and in lean times it's a reservoir of water that might be used up if it's not available from the environment plants can use the water that they have in reserve in these vacuoles to keep the living processes going but eventually using up that um those using up their water balloons their water balloons are going to shrink and so is the plant so that's kind of how plants can wilt and come back the chloroplast is a fascinating structure the chloroplast is where the chlorophyll is found and because the chloroplast is where the chlorophyll is found is the chloroplast where photosynthesis takes place photosynthesis means taking light and making sugar synthesizing sugar from photons from light and if you look at a chloroplast if we take one chloroplast out of a plant cell it's got these distinguishing characteristics it's got its own dna it's a thing living inside of a cell that has its own unique dna and it has these things these hamburgers i'm afraid that's what they were called when i was learning botanians i've never forgotten the thylakoids look like stacks of green hamburgers that's just anyway it's got these things the chloroplast has its own dna and it's got these membranes these membrane bound structures that are shockingly similar to the composition of photosynthetic bacteria there are free living photosynthetic bacteria bacteria being the earliest branch on the tree of life we're up here studying plants way way way way way up here but how did plants become photosynthetic they took photosynthetic bacteria and forced them in to servitude inside their cells and they have lived there ever since and they reproduce themselves they have their own dna it's endosymbiosis that's a blue-green algae cell here's a colony of cyanobacteria we've got a whole episode on the algaes please check out our youtube channel um there it is what is algae uh we released it two or three weeks ago now all of our videos are recorded there so what happens in the chloroplast back to plants i just wanted to show you the origins of chloroplast blue-green algae but now we're back inside of a plant here's one chloroplast the scary krebs citric acid cycle in the calvin cycle and the atp and the adenosine triphosphate and everything that turns people off of botany here it is in a little graphic happening and let's just focus on the biggies the water the oxygen the carbon dioxide and the sugar the good stuff in the presence of sunlight here plants here can take water and carbon dioxide represented here by some fizzy water carbonated water get it sunlight carbon dioxide and water plants can turn that into oxygen and sugar here's the best thing in the world plants are doing us the best favor ever by taking these innocuous raw materials and making us they're not making it for us they're making it for themselves but the fact that plants can synthesize they're the ultimate synthesizers they make the stuff that is the basis of the center of every food web except what happens in the middle in the in the depths of the ocean and the hydrothermal vents that's another episode thus we have the diversity of plant life on earth that's what's happening so what are the major groups mosses ferns gymnosperms and flowering plants what do they all have in common these crazy cell structures made of cellulose the cells are made of cellulose which has many applications beyond what the plant intends them for that central vacuole that's unique to plant cells and the chloroplast the endosymbiotic blue-green algae it's no longer bacteria but it is clearly derived from endosymbiotic bacteria so let's finish up with how can these organisms that are stuck to the ground how are they able to respond to the environment long enough to reproduce that's the whole point make your food reproduce you've got to do that at least once or or your life is not worth living no how do plants respond to the environment the only thing they've got are hormones to respond and there are a fascinating variety diversity and number of different plant hormones that have very direct and oftentimes very specific functions that they play in plant development and implant response to stimuli we've all certainly abused house plants to the point where they don't have enough light and they bend towards the light this growth is a hormonally driven response to insufficient light so plants they depend on the sunlight remember they need that sunlight to take the carbonated water and turn it into sugar and [Music] so in the absence of enough the plants have to bend but these plants aren't muscularly moving there's a hormone at work that is causing the cells on this side of the stem even these little seedling stems causing the cells on this side the side that's away from the light to lengthen and the cells on this side of the stem to contract or not get as big which results in a curvature of the entire individual that's hormone driven this plant isn't actively moving that movement is driven by signals being provided to the cells on how to grow or not grow how to elongate or not elongate here's a plant where the ground dropped out from underneath it when it was a very very young little sapling hormones responded to a gravitational stimulus and informed cellular growth throughout the plant to elongate on one side and and stay small on another side so that as this tree grew it appears as though it's writing itself it's just growing in that direction you see what i mean now a full grown tree might not have enough life in it might not have enough plasticity to write itself up like this this obviously happened very early in this plant's life and it has over the years begun the process of uprighting itself but still it's due to the action of hormones just two examples of the jillions of applications that hormones have in plant development reproduction i mean when when should a flower open what environmental signals are going to have to be just right for the flower to open so once the environmental signals have been detected by the plant how does the plant signal to its flower buds that it's time to open all at the same time so that the pollen is available to the pollinators to move to the other plant to get the pollination going hormones synchronizing this process the sequential fruit ripening also has to happen in a particular way you don't want it to be too fast or too slow has to be just right hormone driven the speed at which tissues develop grow divide die hormones decide when it's time to turn to break down all that chlorophyll and turn into the pretty autumn leaves and then eventually fall from the tree completely the formation of of novel organs at particular times of year it's time to make potatoes so the hormones say to the potato plant we've been growing all summer it's about to get cold or it's about to get really dry switch from growing into putting all that carbohydrate into a storage organ these kinds of processes are hormone driven the fact that we have these chemical substances complex chemical substances that appear in various branches of the tree of life and have these crazy effects on us and on all living creatures really does kind of underscore what might be obvious to lots of people that we're all just organisms at the end of the day even those of us that can study organisms we're one of them we're we're an organism of many under the same influences under the same pressures and driven by a lot of the same processes hormones plant hormones can even teleplant to do something it's not meant to do so in an area of a stem that for all intents and purposes is supposed to produce leaves for photosynthesis hormones can say nope we're not in that business anymore we got a switch tactic it's time to put some roots i know we're in the air but i we need to make some roots up here right now because something's happening that's going to require roots so it just blows it can very easily blow your mind the complexity and it's almost as it appears as though you know the plant is knowing what it needs and responding these are all down to these complex environmental as manifest by the activity of plant hormones insects certain insects have actually figured out how to synthesize artificial plant hormones to stimulate plants by introducing these artificial plant hormones to get the plant to grow tissues that benefit the insect has no benefit to the plant whatsoever no harm but no benefit whatsoever the wasps certain species of wasps they use their stinger their venom is modified instead of something to hurt or defend themselves it's modified into a substance that mimics plant hormone so the wasp will sting the plant sting quote unquote they'll inoculate the plant with this growth hormone mimic modified venom and the plant starts to grow this wart this growth this mass this spongy mass of tissue that we call a gall that spongy tissue is just perfect to feed the little wasp baby so the gall wasps have figured out how to mimic plant hormones they can introduce the mimic hormone and an egg into plant tissue and then the plant goes and raises its child cunning okay i've gone half an hour over really really appreciate your attention especially with this extra time that you've spent botanical science for beginners obviously just scratching the surface hope you enjoyed today's presentation there's so much more to learn again if you have any questions please do put them in the q a um i don't think i have a poll for you today lucky lucky day there's no poll for you today um i see we're having a couple of q and a's coming in so i'll go ahead and open that we do have a poll we do have a poll it's not your lucky day not only have you been kept for half an hour more we have a quick series of questions for you while i have a drink of water and thank you for your response thanks for answering just a few simple questions as part of university of florida of course we're always polling getting data the data is never assigned to an individual um i guess uf hasn't figured out how to make money on selling people's identities so we don't i know that sounds really wrong but anyway crass anyway your identity is safe with us we're just collecting raw data i have to plug if you want to learn more about the differences between some commonly confused species lara and i have put together a field guide called this or that it's available from the ifas bookstore ifisbooks.ifis.ufl.edu unfortunately not available for mania any of the other booksellers online just the through ifis books you can always phone extension service they can help you find ifis books it's an easy field guide commonly confused species if you do think of any questions any comments any concerns any complaints anything that we can use to make our presentations better never hesitate to reach out i thank you for your intention today and we hope to see you again soon thanks for joining us you