hey everybody we're back again and now we're going to talk about plant sex yay on a day when I can't even believe this is happening outside crazy snow doesn't matter salamanders are moving anyway so they're okay so let's talk about plant sex plant reproduction more specifically so this first sorting objective wants you to explain the mechanisms of asexual reproduction in plant so we're going to start there before we go to sexual forms and what you all of course see is that there's many similarities to asexual reproduction in plants as to animals but there are some decided differences as well so most plants can reproduce asexually and can make clones and I wish we had time to go into all the different kinds of things plants can do that animals can't because they're crazy crazy weird but in terms of reproduction so they can reproduce asexually most plants actually produce sexually but let's talk about those different forms of asexual reproduction in plants some of which we've actually already covered this semester so we talked about what rhizomes are right so these are modified stems that are growing underground and with rhizomes you can have these independent individuals that grow up along the continuously growing rhizome now if if any of these individuals was to get was to be separated from the rest of the rhizome then that would result in an independent individual growing and so that would represent asexual reproduction so you can think of this as being almost identical to fission in fact it is identical to fission in animals they also can reproduce asexually via corms so corms are basically underground bulbs so they're there modify their modified underground stems but they're basically bulbs and so they would be used for storage of materials of nutrient materials over the winter but what you have here is a parent corn and you can see all these little individual new corms that are developing and these will ultimately develop into full individuals just like you have here on top so you can think of this as being virtually identical to budding in animals where here you have a plant and you have a little-bitty you know mini-me that's developing and will eventually like pop off and become its own separate individual so second form of asexual reproduction implants this is our really cute and fun one so these are plantlets so along the margins of leaves of some plants that can do this you'll have these little individuals that will develop and grow these will actually fall off the plant followed the ground and will continue development and will form a fully mature additional new plant so that's a third form of asexual reproduction in plants and lastly is a poo mixes so what happens in some plants is you can have seeds this is a very familiar dandelion that I'm sure you're all very familiar with so these seeds can actually be produced via mitosis and they can then you'll go off in the wind as you see that happens in the spring so when seeds develop without the incorporation of male sperm then or with pollen grains then this is called a pom ixus so you have four different kinds of sexual reproduction implant right so you have eight the mixes you have plantlets you have corms and you have rhizomes okay so now let's go on to the alternation of generations so this is a hallmark feature of many plants excuse me and it's called this because not only is there a sequence of going from one generation to the next which of course we do in animals but in this case each generation is alternating between haploid and diploid and I think it's important to note that while of course and produce haploid gametes that then fused into diploid organisms most of the time diploid zygote that's not what we're talking about in plants in this case not only is it all is it an alternation of generations of haploid and diploid but the haploid isn't just gametes these are multicellular individuals where all of the cells are haploid so let me show you so oh so most plants reproduce sexually producing offspring that are genetically different from one another and from their parents so just like in animals ok the generations are referred to as the sporophyte generation and the gametophyte generation both are multicellular so we're not talking about single cells here although there is a portion where a single cell is involved but both are both are multicellular the sporophyte is the diploid stage the gametophyte is the haploid stage and you can think of it as the let's go let's go through the pieces together ok so this slide lays out all five steps let me just talk you through them and I'll show them to you on the next slide on the figure ok so you have sporangia which are cells within the sporophyte remember the sporophyte is that diploid multicellular stage but that stage is going to produce haploid spores and it's going to do it by meiosis okay the spores again haploid are then gonna undergo mitosis and develop into a multicellular haploid gametophyte and I know it's like a total mind blow at this point if you're not already familiar with how this works so I find I have to go over there several times and look at the figures to really get it straight in my head and it's really helpful if you can look at all kinds of different plants to see how they do it ok so that haploid gametophyte stage so remember it's a multicellular it's an organism right it's a plant and you can see it so haploid cells so within that stage it's going to produce gametes the gametes are going to be produced by mitosis which makes sense right you're gonna go from haploid to haploid okay those gametes which are haploid or going to fuse they're going so you're going to have fertilization and when they fuse they're gonna form the diploid zygote stage and then that zygote is going to undergo several stages of mitosis develop and grow into the diploid sporophyte stage so now you're back to number one okay alright let's see this on a diagram it'll probably make more sense okay so we're gonna start here with this flower okay so in this case the flower so this is this by the way this figure is representing a typical angiosperm plant it's a little bit stylized typical angiosperm plant and so all of these cells here that you're seeing right here these are gonna be diploid okay so diploid plant diploid flower so on this particular flower and we'll talk about flower types in a minute but on this flower you have anthers right so you have your stamens and you have your stigma style and ovary right so you have your carpals and your statement okay so if you look at the anther and then in a minute we'll look at the ovule so in both cases these are diploid structures okay but there's gonna be a cell within this so this is called a micro sporangium this is called a megasporangium okay and there's a cell in each right here's the megasporangium here's the micro sporangia here okay the cell are going to undergo meiosis so they're gonna go from diploid to haploid and when they do they're gonna form spores the microspore is the male version haploid the female is called the megaspore so microspore megaspore so these are each haploid cells okay produce BIA meiosis okay okay now what's gonna happen is within these sporangia right there's going to be mitosis so each cell is going to undergo mitosis it's going to divide in this case each micro spore is going to divide to form two cells and this is the pollen grain so both of these cells are haploid so remember you went from the haploid microspore to these two spores together these spores are going to form the pollen grain so one of these is referred to as the we're gonna go over this in a minute so there's the generative cell and the tube cell okay in the female so this megaspore right here haploid it's gonna undergo mitosis by the way recall that this single megasporangium sorry megaspore a site this large megaspore a site is gonna undergo meiosis you're gonna end up with four cells and you do this with the micro spore - so the micro sporangia and microspore Oh site is going to undergo meiosis for four cells but you're only seeing one here we're only showing you one the other 3 do exist in this case what happens though is you get four cells but three of them are gonna regenerate and you'll just you'll just end up with one egg very similar to what happens in humans right so you have the the single cell that as it undergoes meiosis you're gonna have four cells but three of them are gonna be polar bodies and only one's gonna be the egg okay so same thing here so these are haploid but this megaspore is gonna undergo mitosis it's gonna end up forming eight haploid nuclei again through mitosis and together this is the female gametophyte stage this pollen grain this is the male gametophyte stage okay so haploid multicellular stage now don't get too excited it's not like you have a haploid plant going on here hold your horses because you are gonna see an example of that in just a second okay so it's important to note that in angiosperms not only that you had this gametophyte stage so multicellular haploid stage it just happens at an angiosperms this particular stage has been considerably reduced in more ancestral plants this gametophyte stage is dominant you actually see these plants that are haploid out in the field and they form a more dominant stage in the lifecycle of those ancestral plants but you don't see that in angiosperms i'm going to show you that life cycle in just a second okay so then we're gonna go over the details in a moment but then pollination occurs so you have this pollen cell that's going to be dispersed somehow and various plants do it differently but it's gonna land on the stigma of the female reproductive parts so remember what's happening here right so this is just a full tube right it's just full tissue there's no tube there so this tube cell and the pollen grain is basically going to Minecraft's its way down in through the style it's good and and then by the way this generative cell again it's haploid it's gonna undergo mitosis form two sperm cells so they're all gonna travel down this tube until it gets into the egg it's going to go through fertilize we're going to talk about fertilization in just a second once it fertilizes right one of the sperm is going to fertilize the egg now you have a diploid egg here and it turns out you're gonna find out in a second there's actually two sperm right so one's gonna fertilize the egg the other is gonna fertilize these two it's going to fuse with these two nuclei from the polar bodies forming triploid nutritive so this is going to be the endosperm or this is what's gonna eventually develop into the endosperm so now a point being is that you have two haploid gametes came together fertilization now you've got a diploid cell here that's gonna undergo several rounds of mitosis when it does it's gonna form a seed and isn't that cute look it make it look like it's in an apple it's gonna form the seed within this fruit it's gonna undergo multiple sequences of mitosis hopefully ultimately it's going to get dispersed and now you have your diploid sporophyte stage here that's gonna end up hitting the ground drill developing and growing and then developing flowers and starting all over again that makes sense I hope so hopefully that's clear we'll go over more of in class in contrast by the way here's a slide that's demonstrating more primitive plants that things like mosses ferns bryophytes in general and I just want to highlight a couple of things from this slide I would definitely look at this slide in detail and try to commit it to memory if we start over here so this is the plant that if you were going to go out into the forest this is what you'd see so when you see mosses or ferns the dominant form that you're looking at is the haploid gametophyte stage okay so that's what you're seeing here haploid what happens is when they undergo sexual reproduction there are male forms and there's female forms in this case by the way it's really important these plants they're generally very short low to the ground and they're often in wet environments and they have to be for reproduction because the sperm actually swim away from the male plant and then go and fertilize the ovaries the eggs on the female plant right so and you can actually see this happening on rainy nights if you're lucky true story anyway so you got sperm swimming to the eggs they fertilize the eggs on this gametophyte stage right when that fertilization event happens now you're taking two haploid cells fusing them now you have a diploid cell right so now you've got this diploid zygote that's going to undergo many rounds of mitosis to form this sporophyte stage so here's the gametophyte stage and in a weird sort of scientific stranger than fiction the sporophyte stage is growing on the gametophyte stage so how cool is that and in these capsules what's going to happen is you're going to have the production of spores right via meiosis so you're going to go from this diploid stage with these diploid cells via meiosis to produce these haploid spores which will then be released they're dispersed by the wind so each cell goes out remember these are haploid when they hit the ground they'll start dividing via mitosis they'll start developing this gametophyte stage and the cycle continues so this is a typical bryophyte or ancestral plant nan and Esther angiosperm life cycle and speaking of which if you if you were to examine the gametophyte and sporophyte stages in a number of plants and see which ones the trend from from dominant gametophyte two dominant sporophyte what you find is that many ancestral some would say primitive all I usually refer well I usually refer or I prefer not to use that term but ancestral plants had a tendency to be dominant the dominant form was the comida fight stage and as you work your way through the phylogeny once you get to the angiosperms and the more advanced plants they have a tendency to have a dominant sporophyte stage instead of a commute a fight stage ok so now let's kind of ratchet down a little bit talk about the parts of a flower in their functions so this is sort of a stylized diagram of a plant or sorry have a flower that has all the major bits on it so the carpel is the female portions and it consists of the stigma this is the sticky part where the pollen is gonna stick down the style which is this it's going to be a tube it's not a tube yet it's just dense tissue and then the ovary and then within the ovary there can be several different compartments each of which consists of and ovule and within that ovule ultimately an egg will develop the male structures are collectively referred to as stamens and they consist of the anther this is where the pollen grains are going to be dispersed from and then the filament and then it's really important to note the petals around the outside and then the sepals which collectively together are referred to you as a Kailyn all right so what are the functions of all these different parts of the flower so the sepals going from bottom to top right you see these here so they're generally green and they're photosynthetic relatively thick so when the flowers are initially developing in their buds these sepals protect the flower buds keeps them safe as they're growing and then once open they actually frequently there can be nectaries in the bottom and said they're protecting the nectaries as well and as I mentioned before all of the sepals together are referred to as their calyx the petals are of course often brightly colored and their primary function is to attract pollinators for those plants that are pollinated by other organisms that are not when dispersed and it turns out there there can be a lot of adaptations among plant petals sorry flower petals in terms of the coevolution with the pollinators that are pollinating those flowers and you'll see some examples in just a second by the way one thing that's being highlighted in these pictures is the fact that many pollinators can see in the UV and plants actually will frequently have different patterns that you can see only in the UV and that we don't see to the naked human eye okay so at the base of the petal can be the nectary glands and nectar can be harvested by pollinators and this is a useful way to attract pollinators to you for more efficient pollination and it's a win-win situation they're helping the plant get pollinated at the same time they're getting something to eat so the stamens are again these are these are going to produce a feed the male gametophyte or the pollen grains and as I already mentioned you have the the filament this is the slender stalk and then the anther where the pollen grain production is going to occur and in the carpool so you're gonna have the eggs being produced and so it's going to produce the female gametophyte which is then to produce the eggs so everything that you're seeing right here this is diploid right here okay so in continuing with the female so the stigma again is the sticky trap that receives the pollen the style is the stalk and the ovaries the enlarged structure in the base oh sorry as I mentioned inside the ovary the female gametophyte SAR produced in audios and we mature are going to produce eggs and then let's talk about different kinds of flowers and this is going to be a bit of a simplification but flowers generally speaking can come in two types you can have flowers where both the male and the female parts are on that flower at the same time like you see here that's called a perfect flower but you can also have flowers where it's just the male portions but you know the pollen producing portions or it can be the egg producing portions that are only on the flower and those flowers are referred to as imperfect flowers now contrast those terms with when you're looking at the plant the entire plant okay it's referred to as being mon asia s-- if an individual plant has both male flowers and female flowers okay so you can have them you can they can be perfect flowers or they can be imperfect Flowers doesn't really matter but when an individual plant has both male and female flower parts on them that's referred to the plant is referred to as being mon asia's okay so corn corn is an example of a Monet she's plan um dioecious plants are ones where when you're looking at the whole individual plant it has only male flowers ever or it has only female flowers ever and I didn't put this picture on here but cannabis apparently is deiicious good to know okay so now let's go down into the reproductive process but more deeply and talk about gametophyte is being produced in angiosperms and by the way isn't this a fabulous scanning electron micrograph the is pollen grains turns out pollen grains so you know how I was going on and on about him EP knees last week turns out pollen grains morphology is highly variable as well species specific and so you can actually dig in the soil or you can even find fossilized pollen grains and you can identify what those plants are just from the morphology of the pollen so cool okay so let's start with the female process so remember here's your whole carpel here's your ovary and if you do if you look up close right now this is at the beginning of the stage so this is a megasporangium it's diploid and here's the megaspore Oh site whenever you see site c y te at the end of the term so you can think of that as being the immature version of what's ultimately going to come okay so this is the megaspore a site and this is eventually gonna form the egg or the spore so the sporophyte forms the Spore okay so excuse me so you got the megasporangium this is diploid and the megaspores site this is a single cell that's diploid it's gonna undergo meiosis and as as always happens with meiosis you always end up with going from a one diploid cell to having four haploid cells but all haploid cells don't necessarily continue to do to perform a function some of them to generate out and that's what you see here so the megaspore site diploid undergoes meiosis you get four cells that are produced four haploid cells but three of these are gonna degenerate and you're gonna be left with a single megaspore so the megaspore site eventually divides and forms the megaspore haploid now this haploid cell is going to undergo mitosis and it's going to develop eight haploid cells okay and all of these together within the megasporangium is now going to be referred to as the female gametophyte okay so this is the female gametophyte stage so you had these eight haploid cells and what happens to each of these cells differs a little bit depending on the species that you're talking about but what is generally true for all angiosperms is that one of these haploid cells is going to form the egg which you see right here two more are gonna lie adjacent to the egg and these are going to be the standards they have a function later we'll talk about two of these are gonna form polar nuclei that have a very important function that we'll talk about later and what happens with these ones again is going to vary from species to species so we're going to focus on the similarities okay so here is the sporophyte stage here is the gametophyte stage okay and the comida fight stage has produced the gametes here you go egg and now we'll talk about the male let's see oh yeah so you should also know all these eggs together so now we don't really refer to this as the megasporangium it's the embryo sac yeah just what I said one of these becomes egg okay and then this is just a close-up so in many angiosperms the embryo sac contains eight haploid nuclei in seven cells because these two are actually gonna combine together so the two polar nuclei stay together within one central cell then you have egg cell and the synergies at the base near it near the micropyle so this is where the sperm from the pollen grain are gonna ultimately enter and fertilize the egg okay so let's talk about the male part so that anther is more appropriately referred to as the micro sporangium or it's filled with micro sporangia and within the micro sporangium is the micros poro site so a diploid cell so this cell is going to divide by meiosis it's going to produce four microspores and these are going to be haploid so microspore si diploid meiosis forms for micro spores that are haploid now each of these cells is going to divide once by mitosis and when it does each of these is going to form a pollen grain and this is the gametophyte stage the male gametophyte stage so everything's haploid and you've got two cells the generative cell which is ultimately gonna form a sperm and the tube cell it's got a tough outer coat as well so here's what happens I'm sorry microphone size is haploid spores all agree and yets got it okay so I'm showing you more and more pictures these cells think you get the picture now let's talk about pollination so what happens with those cells so pollination is the transfer of pollen grains from one anther to a stigma so it's not synonymous with fertilization so pollination is merely the pollen grain dispersing in the variety of ways that they can and then sticking onto the stigma that's pollination fertilization comes afterwards and here I say it occurs when a sperm and an egg unite to form a diploid zygote so they're separated in time and in space so plants mini plants not all but many plants are capable of self fertilization or stealthy and of course this is when the sperm and the egg from the same individual unite and priests Osprey but you can imagine that this could have some serious consequences if it's repeatedly done and if mutations occur so there's many reasons why selfie it's probably best to avoid selfie or there at least maybe it's best to say that there are benefits to not selfie there are pros and cons to both outcrossing which is more common occurs when a sperm from one plant fertilizes and from a different plant so a and B would represent selfing C would represent outcrossing okay so if you wanted to prevent something from happening there's three primary ways that plants can do this so the first is called temporal avoidance oh and I've got some props let's see so temporal avoidance occurs when male and female gametophyte swith in a perfect flower mature at different times oh let's see yeah I don't have a so I have a really good one where you can see but the male and the female parts but this is actually sort of a decent example this is a fake flower but still a good representation of what it looks like in real life so here's the anthers right and the stigma in this case on this plant is way down here at the bottom oh wait that's spatial avoidance sorry this is spatial avoidance that I'm talking about here so if you had this sort of a situation where the stigma is way down here and anthers are way up here it'd be really hard for the pollen to actually fall down and hit the stigma here it could happen but there are other flowers that do just the reverse maybe all the way up here you have the stigmas and the anthers are down here oh sorry yeah no that's right yeah stigma is up here anthers down here and when that happens it's really hard for the pond grains from down here to actually hit the stigmas up here so that would be a great example of spatial avoidance where they actually avoid being close together in space okay temporal avoidance is when let's say you had a perfect flower and you had both the female and male reproductive parts on the flower what those plants can do is you can have say the male parts maturing before the female parts mature on this particular plant so then okay pretend for a second I have two different plants here okay I'm gonna show you two different flowers but imagine just two different plants so if I had only the male parts mature on this one and only the female mature well parts mature on this one then they could safely fertilize the this pollen could fertilize the eggs and then there'd be no problem right so it'd be out crossing again if they were different plants and the same thing would be true if like you had all male flowers and all female flowers in that case if you're if you're dioecious like that there's really little chance that you would ever be able to self anyway so no problem so you can have temporal avoidance where you have different parts that are mature at different stages so that you can avoid selfing you can have spacial avoidance where maybe within the plant you have only the males on one plant that are maturing only the female plants or you can have those stigmas and stamens at different places on the plant where they can't exchange gametes or in this third case molecular matching so maybe this is a case where it's possible you could have sperm that transfers to the stigma on the same plant but there's molecular breakdown and basically the sperm from those pollen grains are unable to complete fertilization within their same plant and so it breaks down so this is called molecular matching so when occurs when plants can recognize self and non-self tissues and the species is self incompatible and sometimes will happen to is the the pollen grains will reach the stigma but then it recognizes that oh wait this is the same plant and then the pollen tube won't grow and go through the style okay so another concept mmm yeah all this pollen right all these all this oak pollen is killing me even in the snow okay so another concept you should be familiar with is pollination syndromes so here I say in most cases animal pollination is an example of a mutualism so a mutually beneficial relationship between two species so in that classic example here you have bees that are pollinating all kinds of bees are pollinating all kinds of flowers and so it's a win-win and where the B is getting probably nectar as well as pollen so sometimes I'll actually consume pollen but they're going to get pollen all over them as you see here and the benefit is the plant is going to have a greater success in pollination so the bee is gonna pick up pollen from one plant it's gonna travel to another flower it's gonna dump the pollen or it's going to accidentally hit the stigmas about a boom bada being you got pollination that's just occurred but there are many examples of plants and animals that are Co evolving through these mutualistic situations such that the plants develop adaptations to facilitate attracting the pollinator and the pollinator has specific adaptations that make it possible for them and maybe only that species to pollinate the plant and then also receive the benefits of nectar and here's a classic example of that so humming hummingbirds are frequently strongly adapted to plants that have a particular kind of morphology and so they have these long tubes that you need to reach way down into to get nectar and these birds not only often have long beaks but they have incredibly long tongues to reach down in there and get the nectar and there's even more examples I'll show you some more pictures in in class and just some amazing adaptations that plants have oh so here you go and here's like a moth that has an incredibly long proboscis that it can reach down into these highly modified flowers and reach the nectar and so this is great because these balls need this plant to feed right and the plant definitely needs this moth in order to pollinate it and so they've evolved together with these adaptations that you can see so pollination syndromes are Suites of flower characters that are associated with certain types of pollinators so two examples that we give here bird pollinated flowers tend to be red not only red but they tend to be red they tend to be unscented and they're open during the day when birds are active moth and bat pollinated flowers have it too to be white or lighter-colored the strongly scented to help you find them at night and they're open at night now of course you should be familiar with the fact that not all plants are pollinated by animals so many have when dispersed pollen and in this case they have different morphological features that facilitate that wind pollination so in like oaks birches pecans and many grasses not all of them many of them they have flowers that have really small petals or no petals at all so they don't get in the way and these species lack nectaries and they don't invest in a lot of structures that would otherwise be required for pollination so everything about them is adapted to facilitate wind dispersion and actually I wish we were showing you better pictures here I had a hard time finding good winds but like these cat kids these these structures that you're seeing right here these are catkins you'll often see these fall to the ground actually here and a couple of weeks you're gonna see them littering the ground and they they fall off the tree once all the pollen has been dispersed and to give you a sense of what this looks like check this out so there's somebody's at the bottom knocking on the tree and all of that is oak pollen that's falling off the tree pretty impressive stuff but I want you to think about the fact that you're now walking a month and inhaling plant semen that's really what that is no I don't wanna watch it again oh there we go okay so now let's describe the events of fertilization and Angie sperm so we've talked about pollination that's getting the pollen grain over to the stigma and that's it now what happens okay so the pollen grains gonna land right on here on the stigma right and then what's going to happen is that the tube cell on the in the pollen grain is going to begin minecrafting its way down through this style so there's no tube here right it's gonna build the tube and then the generative cell is going to divide via mitosis remember it's already haploid but it's gonna divide via mitosis form two cells and those are each gonna form sperm okay so Minecrafts its way down this tube here you go there's a tube nucleus here's the two sperm OOP bonk bonk bonk three it's gonna go all the way down until remember there's that little opening at the bottom the micropyle right so once the tube cell like burst through the micropyle one of those pollen grain sperm is going to fuse with the egg and that's gonna be the zygote if you will but it's not really a zygote you'll see what it forms in just a second the second sperm is gonna unite with those two polar nuclei and boom it's gonna form a triploid cell that that's then going to divide via mitosis and it's gonna form the endosperm or the nutrients for the developing seed so this part is referred to as double fertilization because you've got two sperm and they're each fertilizing two different structures at the same time in two different cells Oh duh so this is just going through telling you what I just told you yeah so forms the endosperm tissue really bad about clicking through these slides sorry okay so now you've fertilized the egg and you're gonna develop seeds and of course fruit because that's the definition of fruits right fruits are these nutritive structures that are surrounding and protecting the seeds of whatever that plant is so what are the parts of the seed well if you were to split them apart now there's different kinds of seeds you've got your dicots and your monocots right so on the outer part of the seed is the seed coat which is going to protect it it's usually a hard kind of a surface right on the inside here's the endosperm so this is kind of the yolk if you will of the seed so it contains the nutritive material it's going to help it to germinate and grow sorry you have the cotyledons right so these are like the the seed leaves if you will sorry so this is the seed leech and this is the sieve my bad so you're only looking at in dose endosperm here in the monocot not over here and then in the very center is the embryonic stem and root so this is what's going to ultimately end up growing into the plant okay so seeds contain stored nutrients increase offspring success and crowded habitats that's what's in the endosperm seedlings can subsist on stored nutrients until they're well enough established to absorb water from the soil and feed themselves via photosynthesis you guys already know this for done experiments in lab that highlighted those functions so here's a typical sort of fruit so the fruit is composed primarily if we're gonna be a little simplistic on this but it consists of the pericarp which is the tissue that surrounds the seeds and then of course you can see all the little seeds inside each of these compartments right so the pericarp protects it but the function of a fruit in general is to attract animals to eat it and to help disperse those seeds now that's not to say that these couldn't drop to the ground and the seeds could then fall out and then grow they could they could grow on their own but this facilitates being picked up and carried and dispersed further and further away from the parent plant so there's different kinds of fruits and we'll just go over a few kinds of these there's simple fruits so these develop from a single flower with one carpel or it may have some fused carpools but usually just one and so examples of this are things like cherries you can have what's called an aggregate fruit so this is developing from a single flower but this single flower has a lot of different carpals and then it ends up with a fruit like this so each one of these little bits is from a different carpel oh and so an example is a blackberry you can have multiple flowers with mult mini carpals that look for master like this so a multiple fruit and a classic example would be a pineapple alright and then what if you had something like if you had something like a carrot yeah that's not a fruit no seeds in that so is a tomato a fruit yes yes it is and so is a cucumber what other kinds of fruits can you think of that most people would think of as being vegetables and it really begs the question why do produce sections erroneously refer to some produce as vegetable when really it's a fruit it's a mystery that ok last but not least just to reiterate the two functions of fruit are to protect the seeds from physical damage and from seed predators and of course they aid in dispersal because they attract these animals that are going to eat them and then are gonna carry them off and either drop bits of them or poop them out and you probably already know that lots of seeds are actually adapted to where they will not germinate unless they've passed through the gut of some animal that has acids and a digestive system such that it'll actually start breaking through that seed coat so that it can germinate neat stuff okay that's all I got on plant reproduction we'll talk more about development in a subsequent lecture see you later