hello bisque 132 this is the beginning of recorded lecture two three uh continuing on talking about plants specifically seedless plants so last time i had introduced some background about this group called bryophytes so here's this phylogenetic tree again and as you can see bryophytes is uh sort of a umbrella term that encompasses three clades um and we're going to look more closely at these three at this point so i i like this phylogenetic tree because you know it does show the stepwise fashion of things but it might be useful for some people to look at things in this way instead so this is a table kind of uh that just outlines the phylogeny in a slightly different way so uh all plants are green plants there are the you know the green algae we talked about last time uh here's this bar that says land plants so that as i said it's going to include everything to come and non-vascular plants or bryophytes is you know what we're talking about now and this shows the three groups of bryophytes that we're gonna get into presently uh liverworts hornworts and mosses so this is just a different way of organizing the information take it in whatever form you know sort of clicks with you so okay uh what about liverworts well these are uh some liver warts uh i i guess in ancient times the the thali of some species of this looked like a liver to someone uh hence the name liver warts and they were used to medicinally to treat ailments of the liver no modern scientific basis for this by the way but um you know that's where they get their name liverworts some thali look like a liver uh what else can we say about these well they embody a lot of the uh you know traits that we talked about last time about bryophytes in general you know the the rhizoids and the phallus all that fun stuff uh what i can say about liverworts in specific what's unique about them uh are these gemmae cups or singular is gamma cup uh they produce these structures uh on the gametophyte um that are cup shaped they will actually wash away uh when it rains so they will detach from the gametophyte flow away with the with the rain water uh and then anchor themselves somewhere else and grow into a new gametophyte so this is a type of asexual reproduction so that's what's fun about liverworts gummy cups detach and float away in rain grow into a new gametophyte uh there's no egg sperm involved here this is a form of asexual reproduction so that that's all i got to say about liver warts here again being sort of brief with these very specific groups uh next i want to talk a bit about hornworts um if you want to guess where they earned their name it should be fairly apparent here uh again they have phthali that do photosynthesis and these spikes coming out are the horns or the sporophytes here hornworts because they look like they're covered with horns and here's a diagram a cartoon showing this so yep you've got your phthalus you've got your here's the the sporophyte the the horn sticking up and in here the the structure fits the function why do they have these big tall horns well they're not actually big and tall these are only a couple of inches tall because remember these are non-vascular plants they can't grow very big because they can't transport water and stuff but these sporophyte horns grow tall so that they can produce and release spores so back to the cartoon diagram yep there's one of the haploid spores being released from this uh and yeah the taller you are the more you stick up the better you're gonna be at releasing these spores and having them have a chance of growing somewhere far away from the parent so in hornworts the sporophyte is a tall thin horn and this structure helps to disperse spores on now to the third of these bryophytes mosses again things that we're all probably pretty familiar with growing on uh you know the ground or sometimes on walls or other trees uh they are a tangle of filaments that are photosynthetic kind of just looks like one big mass here but if you were to take one of these and sort of stretch it out you could see it has a shape more like this quote marks for leaves and quote marks for stem because you know it's not a real stem they're not real leaves we won't see that until we have the evolution of real vascular tissue here uh but yeah it's a tangled filament of these photosynthetic organs this is the gametophyte the sporophyte is kind of like the hornworts a structure that sticks up and again for scale this is only a few inches tall uh that you know helps to disperse these spores so mosses the gametophytes tangle of filaments on the ground it's photosynthetic stalks elevate the sporophytes to disperse spores so pretty straightforward here uh so remember these were all bryophytes to go back to this uh our next evolutionary innovation is as you may be able to guess vascular tissue so we call all further all further groups of plants uh fall under this umbrella called tracheophytes so their their ancestor evolved vascular tissue and passed that on to all of its descendants so all further groups uh are gonna be called tracheophytes and if we want to identify this on this figure here again i'm doing both not to confuse anyone but just to show it in different ways uh yep here is uh previously these were non-vascular now we're under this umbrella term vascular all these things to come are what we call vascular plants so all further groups are tracheophytes also known as vascular plants they have a vascular system to transport water and nutrients throughout the plant and so this is going to include xylem and phloem we'll talk more about this in a later chapter on plant anatomy and structure but they've got these tubes these transport systems to transport water and nutrients throughout the plant in roots stems and leaves so no more quotation marks here we are going to have real roots real stems real leaves in in all further groups a couple of other features uh that go along with this so the vascular tissue allows these plants to grow taller and larger because they can transport stuff throughout but it also increases their need to support their weight as you grow taller so tracheophytes also have a compound called lignin in their cell walls it makes them stronger so they can support their bigger height roots anchor plants better than the rhizoids that we saw in previous groups in addition to being able to transport stuff and leaves again because they can transport stuff now have a much larger surface area to do better photosynthesis and to transport that to the stems and the roots into everywhere else all of these factors allow for larger plants this is a there's a huge selective pressure to try to be larger because taller plants access sunlight better you know mosses can eke out a living on you know on the forest floor but you're going to be very successful if you can grow taller than a moss and be the first one to to get to that delicious delicious sunlight so that's the the reason for these evolutionary innovations uh larger not just for the sake of being larger but it gets you to the sunlight first another thing that we see in tracheophytes is a flip-flop of the prominent form so in bryophytes it was the gametophyte that was prominent and the sporophyte was just a little thin thing sticking out in tracheophytes which again includes all further groups the sporophyte is now prominent and the gametophyte is going to be a smaller structure sometimes even microscopic but not the prominent prominent form of the plant now we kind of have to skip ahead to the next evolutionary innovation that the next evolutionary innovation is going to be seeds uh but before and the reason why i'm bringing that up uh is because we can split vascular plants into two groups ones that have seeds and ones that don't have seeds so obviously we'll talk about these first these seedless vascular plants so there are two major groups of seedless vascular plants and they despite all these fun innovations we just talked about they're still limited by this factor sperm still needs to swim in order to reach the egg so the next couple of things we're going to talk about the ferns and the fern allies these seedless vascular plants still need to live in moist environments they need that water for their reproduction okay so yeah that's true of these seedless vascular plants lycophytes and terophytes let's get into these start with uh lycophytes uh so lycophytes also known as a fern allies just sort of an infernal informal name for these things lycophytes include club mosses quill warts and spike mosses quill warts look pretty quilly to me uh club mosses not to be confused with the bryophyte mosses but it's just a name um and uh and it's spike mosses like this cool resurrection plane which can survive desiccation you know complete loss of water and then when it gets water again sort of unfurl turned green and it was never really dead to begin with but it kind of looks like it's coming back to life uh these are three examples of groups of lycophytes and that's really all i want to say about them you should know club moss's quill warts and spike mosses are all under this category of lycophytes or fern allies there is a little bit more to say about the other group of seedless vascular plants uh terraphytes silent p so pterophytes uh pterophytes is going to include whisk ferns um yeah it looks kind of like a whisk uh to me uh horse tails which um there are actually some of these growing at uh outside a tech point unless they've changed up the landscaping there so these can be found on campus kind of looks like a horse's tail i suppose uh and there's a big one ferns so real ferns not just their quote-unquote allies so terror fights includes whisk ferns horsetails and real ferns so ferns are not the only plant that has this sort of leaf structure where you have little leaflets coming out on either side of a main stem we're going to see this in other other groups as well but they are unique and distinguishable by their fiddleheads so the way they grow their stems and their leaves is in this fiddlehead which unfurls as it comes out so fern's uh leaves develop as fiddleheads which unfurl as they grow and now i want to talk more about ferns uh to to really get into them to talk more about their life cycle because there's something really weird and interesting that's going to happen here so of course the fern life cycle is a haplodyplantic life cycle all of these land plants had a haplodiplotic life cycle but what's interesting about it has to do with the gametophyte in the sporophytes so okay sorry this figure is is flipped and here the the gametophyte was on top and the sporophyte was on bottom but now i need to sort of switch our brain around haploid gametophyte is now on the bottom and diploid sporophytus on top mentally flip-flop yourself there so uh so far so normal let's start with the sporophyte it releases spores uh that it creates through meiosis and they grow into the gametophyte uh now this is kind of cool they have uh these special structures called sporangia or sorai is another name for these that are located underneath their leaves so if you see a fern you look underneath the leaf oh you can see those little dots those are things that make spores located on the sporophyte of course uh so sporophyte releases haploid spores from these sori uh located under the leaves here's a zoom in uh of this um the spores of course grow into a gametophyte but this is the part that's weird uh at least compared to other plants the gametophyte is photosynthetic and independent of the sporophyte so uh here's you know showing this gametophyte growing up zoom in on this a little bit more uh yeah this kind of looks like a separate plant in most in most plants we've seen so far and most plants we're going to see in the future one of these is just a structure that grows off of the other one um like in the the hornworts the sporophyte just being a little spike that comes out of the gametophyte and we'll see the opposite when we look at you know big trees and flowering plants but the fact that here in ferns this gametophyte is fully independent it makes its own roots it does its own photosynthesis it lives independently of the sporophyte it is a is a unique feature in its life cycle so the spores uh released from the sporophyte grow into the gametophyte it's photosynthetic independent of the sporophyte um and from there everything kind of proceeds as normal the gametophyte makes sexual structures which produce gametes eggs or sperm there we go the antheridium and the archegonium egg sperm water is required sperm swim to egg fertilization zygote and everything is more or less normal here but the fact that both of these are green and photosynthetic that that's that's the weird part so after fertilization the sporophyte grows out of the gametophyte and uh yep now you're back to sporophyte back to fern okay so uh these were what i said were the seedless vascular plants so the next evolutionary innovation as you can guess is going to be seeds so important to note you know throughout everything i've talked about ferns and stuff like that there are no seeds there are no flowers there are no fruits we don't have any of that stuff yet important to keep in mind none of that has come up yet so the next evolutionary innovation is the seed and it's at this point that the textbook and many textbooks will actually separate these into different chapters so we move to a next chapter to discuss this um a group that we call seed plants so go back to this phylogenetic tree here spermatophyta we're talking about seed plants now and you know back to this diagram now we are talking about seed plants so again this is sort of like a step ladder these seed plants have the ability to live on land uh and they have the ability to to have vascular tissue and now they have the the evolutionary innovation of seed so it's building off of itself so as you can see there are a couple of groups of seed plants here but a few things to discuss before we get into those division spermatophyta is known as seed plants i mentioned this before uh all further groups the sporophyte is gonna be dominant uh but in seed plants it's even more dominant than it was in ferns and i mean the fern is still much bigger than this fern gametophyte even though this is independent this is still definitely the prominent part of the fern but this is taken to an extreme in seed plants uh in seed plants the gametophyte is just microscopic it's definitely not free living and speaking of these gametophytes you've probably heard of pollen before uh pollen is a male gametophyte it comes in all sorts of fun sizes but all of these are definitely microscope images to be able to see these individual pollen granules pollen is a male gabito fight structure it produces sperm and this is a big one it's released from the sporophyte and dispersed by wind so this is huge so in ferns and all of the other land plants we've seen so far the gametophyte is on the ground on the land somewhere and the sperm it produces have to swim in order to get to the egg now in these seed plants the gametophyte the male one at least can travel by wind because it's so small and lightweight it's gonna you know reach the female gametophyte and eventually make its sperm but this opens up a lot of new lifestyles and and airy environments in which they can live these uh these seed plants don't need water for fertilization anymore and that's big they're called seed plants but i mean pollen plants is a good name too because this is a big upgrade uh over needing water for fertilization uh the other big evolutionary innovation is of course seeds uh so uh you know see the plants who would have guessed it they have seeds uh the seeds do a couple of things the seeds uh protect the sporophyte embryo so inside of a seed is uh essentially a baby plant it's already gone undergone quite a few cell divisions it's grown to to an extent uh and it has sort of paused itself in its growth so the seed coat protects this baby plant there is uh two varying degrees depending on the species some amount of stored food inside of here the seed also allows this uh baby plant this sporophyte to delay its growth so seeds protect the sporophyte embryo and delay germination this seems like a small point but but it's kind of a big one again if we compare this to some of these older plants this fern you know releases spores and you know if they land at a good time if they get in a good environment that's great but if they end up landing somewhere where there's not enough water or the conditions aren't good or whatever they're just gonna die there there's no choice to hmm this is a good good time to start growing or not either you can grow or you can't the seed allows this sporophyte embryo to wait inside protected and start growing when conditions are good so that greatly increases the the success chance of this actually you know making it to adulthood the ability to delay germination or resu resonation resumation resuming its growth uh until uh until conditions are good okay so these were both uh you know the seeds and the pollen uh these were both um evolutionary innovations that applied to seed plants in general but of course there are two groups of seed plants uh let's get into these now starting with gymnosperms so gymnosperms you you see gymno uh it actually is the same word that's part of the word uh gymnasium you might think this has to do something with exercising or working out uh well jim technically means naked because of the you know the naked exercise that the greeks like to do the gymnasium was a place to be naked and work out uh and so gymnosperms if that's a picture of pain in your head uh gymnosperms means naked seeds so what's so naked about these plants or their seeds well they're naked because they don't have an ovary around the seed which means no fruit and no flowers so they're kind of defined by what they don't have as as cool as seeds are this first group of seed plants no fruit no flowers so they're not completely naked though uh these uh the seeds of gymnosperms do have modified leaves called sporophylls that surround the seeds and you can take a bunch of these sporophylls and form something called a strobilius which is an arrangement of sporophylls around a central stalk this might be sounding kind of weird and foreign and uh strange it's not it's just a pine cone or at least a pine cone is uh one form that a strobilius can take so a pine cone is an example of a strobilus each one of these individual sort of scales uh is a an individual sporophyll a modified leaf essentially and there's the seed uh on on each one of these so not a fruit uh not a flower but i mean it is some sort of protection for these quote unquote naked seeds so an example of a strobilius is a pine cone uh and you know traditionally pine cones look like this uh but in some of these gymnosperms it can look a lot like a fruit that's just a superficial resemblance again i said gymnosperms don't have flowers don't have real fruit uh just a disclaimer sometimes these strobili can look like fruit even though they're they're not technically fruit they don't develop in the same way now a couple of terms to throw out here uh gymnosperms can be depending on the species monovicious or dioecious so okay mono means one and di means two so what does this refer to well it refers to uh reproductive organs to sex so monovicious reading from the key terms now describes a species in which male and female reproductive organs are on the same plant so there's no female plant there's no male plant any given plant has both of the reproductive organs that's what look what we're looking at here with this pine tree it's going to be a male cone that's a female cone it's called monoisis because there's just one type of plant that has male and female dioecious describes a plant in which the male and female reproductive organs are carried on separate specimens so we're going to see some examples of this but yeah this is kind of weird because most plants are are mono-ishes but yeah some gymnosperms you could say oh that's a female tree that's a male tree it only has male reproductive organs or female reproductive organs uh respectively so just gonna throw these out as we go through so be familiar with these terms there are four major groups of gymnosperms so let's go through these uh somewhat quickly uh number numbering these in no particular order the first is phylum coniferophyta commonly known as conifers here are some conifers we're all very familiar with pine trees of all sorts um these are monoishes they're in that term out again most are evergreen as we know they don't lose all their leaves at once in the fall they stay green throughout the winter uh but what is fun uh as i said most are evergreen there are actually some conifers that are deciduous they lose all their leaves in the fall so our lob lolly pine and ponderosa pine these things are evergreen uh junipers uh are evergreen but yep here's the weirdo the larch uh this is a gymnosperm a conifer but it loses all its leaves in the fall so it's kind of interesting some are deciduous okay moving on to a type of plant that we're maybe less familiar with another phylum within gymnosperms is phylum cycadophyta called cycads uh cycads have leaves that would probably make you think that they're a palm tree this palm type leaf and as i mentioned with ferns we're going to see a lot of plants that have this basic you know long stock with leaves on either side whether it's a palm tree whether it's a cycad whether it's a fern this is all convergent evolution this is just an effective way to arrange your leaves around stalk so we see a lot of different groups with this sort of leaf leaf form so cycads have large palm like leaves and monstrously large cones i don't know if you get a sense of the scale here but this is this can be multiple feet long uh and all species so large palm-like leaves large cones all species are dioecious uh so this you know is a either a male or a female cycad and this is another cone where these look like you know juicy delicious berries they're not they just kind of superficially resemble fruit uh this is not an actual fruit this is this is a modified cone with a seed inside so these are cycads moving on phylum ginkgo phyta called ginkgos ginkgos are dioecious so remember that means two separate sexes here is a male ginkgo tree uh with male reproductive organs producing pollen this is a female ginkgo tree with these uh you know female reproductive organs and again kind of looks a lot like fruit but it doesn't come from a flower it doesn't develop in the same way there's a seed inside male and female so dioecious plant uh they're deciduous deciduous uh and they're very tolerant of pollution so this is kind of fun that these are very very hardy trees uh and they will oftentimes be planted in uh you know inner city locations to try to beautify sidewalks and stuff like that because if you've got cars and buses and stuff driving around they can handle that they can tolerate high levels of pollution uh and so they're they're effective in those environments in fact uh it's not terribly polluted but i'm pretty sure there are a few of these planted around tech campus i think one in front of keeney hall if you want to go searching um for ginkgos on campus uh and finally um the last of the gymnosperms phylum netophyta the g is silent netophyta uh i'm just i'm just gonna say diverse members because you know as far as structure and anatomy goes man these really run the gamut this doesn't look like a pine tree at all so this is kind of surprising that this is a gymnosperm uh this well whichia very very cool looking plant lives uh hundreds and hundreds of years very fascinating plant in its own right and then yeah the ephedra over here the red structures which again look like fruit uh but they don't come from flowers they don't develop in the same way they're just a modified cone not actual fruit all i'm gonna say about the nanophytes is diverse members because otherwise it's just too much to get into the specifics at sort of a deeper level but all four of these the conifers the cycads the ginkgos and the netophytes these are all under that umbrella of gymnosperms so i have one more thing i want to talk about gymnosperms uh before we move on to angiosperms but this is typically where i do run out of time in this particular lecture period so we will talk about life cycle of gymnosperms specifically conifer life cycle we'll do that in the next recorded lecture