 Okay, so I guess it's time to get started. All right, so the lecture exam is going to be a week from Monday, and there'll be 50 questions from me and then the rest from the other two instructors. And as far as running this review goes, and there's a lot of material to review in an hour, but I thought quite a lot about the exam, and I wanted to go over some general points that I think you should be sure to study. I mean, people have asked me what depth of study they should go into, and I definitely want to reiterate that the book is just a supplementary to the lecture material, so what's on those slides that I've made PDFs of and posted is the material you're responsible for, and the reading was just to augment that to try to help to understand those concepts, rather than if they're new concepts and terms that come up in the reading, you don't need to be able to recall those. So I know that there is some material I didn't get to in the assigned reading, and that's really just to put things in context, rather than to provide you with new information that you're responsible for. All right, so one of the first things I want to mention is, as far as all the different groups of organisms we covered, the major groups that we talked about you should be familiar with. I mean, we talked about these three domains of life, the bacteria, the archaea, and the eukaryotes, eukarya. But we didn't focus on a lot of these groups. The main ones we focused on were the fungi and the photosynthetic groups, and just these main groups are the ones that we talked about, in addition to, of course, land plants. So the fungi, the major groups of algae and the land plants, and we went into more detail than just this, of course. We went into, for example, in the fungi, the major phyla, those five major groups, and in the algae, we didn't talk much detail about the major clades shown here as far as taxa within those, but you should be familiar with the characteristics of these groups that I talked about and be able to, you know, distinguish a dinoflagellate from a diatom or a brown algae from a red algae in terms of the sorts of things we talked about, not beyond that, but those are the, that's the level of detail I'm looking for. I wouldn't be asking you to recall a particular genus or, you know, fine-scale taxon of some kind within those groups, but there was quite a lot of time spent on these different groups, and within the land plants, of course, we talked about bryophytes, vascular plants, seed plants, and then within the seed plants, gymnosperms and angiosperms. So, and within the angiosperms, we spent quite a bit of time comparing the eudaicots and the monocots' characteristics there. So it's that level that we covered in class that I want you to study. Are there questions about that? All right, so as far as the life cycles go, there are a lot of life cycles that were presented in the reading that I didn't talk about in lecture, for example, brown algae in different groups. You know, that's just for your information only, not for, you know, the exam, but I did show this slide and I would like you to remember the sort of general points about life cycles that, you know, these are sexual life cycles we talked about that involve meiosis and fertilization, and it's the relative timing of those two processes that distinguishes these major life cycles, like what occurs in us and other animals compared to what happens in plants and in fungi. So be sure to be comfortable with this material. You know, keep in mind it's whether mitosis is limited to one of the two ploidy stages is critical to interpreting these life cycles too. So unlike us, the plants, you know, have mitosis going on in this haploid phase and they end up with a multicellular body, you know, gametified multicellular organism that's haploid. So that's completely alien to us and other animals, but it's common, of course, in the, common to all the land plants and even to some of the green algae and other groups we didn't really talk about. So are there questions about the general life cycle issues here? So these were the five major groups of fungi we talked about and, you know, I'm not looking for a huge amount of detail here, just what was mentioned in the class, which was fairly limited. I mean, the kittrids are that group that still has some flagellated stages that can swim around as far as the spores and the gametes go, which is unusual for the fungi. And they're the sister to all the other fungi. They're an early diverging branch. And like the zygomycetes, zygomycota, they have synacitic hyphae when they have hyphae that remember synacitic, meaning that the nuclei aren't separated by any partitions or partial partitions in the body of the filaments or the mycelium in general. The same goes with these arbuscular mycorrhizal fungi. They're so important with regard to relationships with plant roots. And it's this group that makes up the most of the fungi, the ascomycetes and the basidiomycetes, where we see the septate hyphae. And where you get this interesting situation where plasmagomy and karyogamy, the fusion of the cytoplasm and the fusion of the nuclei, are widely separated in time. And you have this dichariotic stage. Remember, we have two nuclei per segment of each hypha separated by partial partitions. So this is something we just saw in the fungi, right? Just these higher fungi where you have this life cycle, which is otherwise very similar to... Well, it has only the only diploid stage as the zygote, but you have this long period where you have the fusion of the cytoplasm and the fusion of the nuclei, where much of the plant body, for example, of the basidiomycetes is dichariotic, like you can see here with two nuclei per partition. And then they produce these fruiting bodies where you actually get the fusion of the nuclei and myosis occurring right after that to produce sexual spores. So that's... And then also remember that in the fungi, there are these quite a wide diversity of different groups where there's no sexual reproduction that's been documented. And these have been placed in this group, deuteromycota, the so-called imperfect fungi that don't have any known sexual phase. And these are important in medicine, et cetera. But they're an artificial grouping of a lot of different types of fungi. So we did talk about this group as well. And I did mention also the slime molds and the water molds, which aren't true fungi but have been previously treated as fungi. So any questions about fungi that anyone wanted to ask? All right, so one other thing about the fungi, maybe we'll get to it later, but they have a lot of interactions with other organisms, of course. And in addition to being decomposers, parasites and such, they can also be mutualists. Well, they can be in association, regardless of their mode of nutrition, they can be in association with different organisms, like algae, green algae or blue-green algae, in the case of lichens, that mutualistic association that we get. It's important in primary productivity and ecosystems. And also the mycorrhizae talked quite a lot about that, both in terms of fungal lectures and later on talking about roots. Remember the mycorrhizae is an association between fungi and plant roots that is important to the success of plants. I mean, it looks like that establishment of that relationship goes all the way back to the earliest land plants, and so that's quite suggestive that the fungi were pretty important to the success of land plants, and they very much are important for the productivity of plants today. I mean, a lot of plants can survive without the mycorrhizae association, but they don't do nearly as well as they do with it. So that's another thing to keep in mind as far as fungi, that they have really important ecosystem functions. So the algae spent quite a bit of time on the algae groups, and remember the algae are not a natural group. The fungi are a monophyletic group. They grow out the water molds, the olomyceses and the slime molds, and pretty closely related to animals, but here the cellular slime molds and the plasmodial ones are closely related. But remember the algae are scattered. The photosynthetic organisms are scattered throughout the tree of life. There aren't any in the archaea, but we do have cyanobacteria. Remember we're fundamental to the evolution of photosynthesis. They're the ones that really evolved photosynthesis, and it's these other lineages that just captured cyanobacteria. And remember there's this, punitively at least, we can only be sure of one event like that that happened where cyanobacterium was captured by an early eukaryote through phagocytosis, basically just engulfing it. And then later we get the split between the green algae and the red algae followed by the secondary symbiosis where we have unicellular eukaryotes that already possess a cyanobacterium or a plastid at this point in their evolution that's been captured and recruited for photosynthesis in this diverse set of lineages. So are there questions about endosymbiosis? Be sure to study this. This is really pretty novel information. Not so long ago we've been able to determine that various of these lineages represent captures of eukaryotes. So the red algae appears to have been the one secondary endosymbiosis that gave rise to the dinoflagellates, many of which are photosynthetic. And they're a big component of phytoplankton responsible for red tides. Sturminopiles are the other major group. The apicomplexans have lost their ability to photosynthesize. They just have a vestigial plastid. I didn't mention them much except to say that the malarial organism is in this clade. But the sturminopiles include the brown algae and the diatoms and the golden browns. So yeah, there are several groups of photosynthetic algae within that group we call sturminopiles which also includes some non-photosynthetic groups that have presumably lost their ability to photosynthesize. I like the old myseed, those water molds that used to be thought to be fungi. Alright, so in addition to understanding endosymbiosis in terms of this, I'd really like you to study, I presented several slides on the evidence for endosymbiosis. I remember there's a whole series of different lines of evidence that support the hypothesis that I presented. And so you should focus on that data too in terms of understanding what's really behind the hypothesis in terms of evidence. Alright, so the alternation of generations then is the main lifecycle we focused on after we got to land plants. All the land plants have this. And again, we have both multicellular diploid organism and a multicellular haploid organism. Having both haploid and diploid multicellular organisms is diagnostic of this type of lifecycle, this alternation of generations. Remember an animal lifecycle, the only haploid phase is a gamete. It's not a multicellular organism. And in the fungi, the only truly diploid stage was the zygote. That's not multicellular. We have myosis right after that. So this is the main lifecycle we focused on for all the land plants especially. And I showed you this example. It's a bit of an aside in terms of the organism, but just to point out that there are organisms like sea lettuce, which is a green algae where you have very similar haploid and diploid phases. And mainly showed you this example just to make it a little easier to understand this alternation of generations because in the land plants, either one phase or the other is so highly reduced, the gametophyte or the sporophyte that it's often hard to kind of picture those as distinct organisms. But they are. And so remember the sporophyte is the spore producing plant. Spores are produced by myosis. So we go from diploid to haploid here. But unlike an animal where after myosis we have gametes, here we have spores. And spores unlike gametes do not fuse with one another. They germinate to create an undergo mitosis to produce a haploid gametophyte. And so in this case then we're producing gametes by mitosis rather than myosis. Myosis occurred back here. That's totally unlike us in that sense. But the gametes are genetically identical to the gametophyte. And then we have the fusion of the gametes and then the formation of the zygote and new diploid sporophyte. So this is important to remember too that the land plants are intimately related to the green algae. So what we used to call green algae and what we still do today loosely is a paraffyletic group. It's not monophyletic. Some of the green algae are more closely related to the land plants than they are to other green algae. And remember these are freshwater green algae. So the land plants didn't come out of the ocean. They didn't descend from some marine form directly. The conquest of land was via water into the freshwater and then to land. So it's a stepwise process that appears. Okay and so then we talked about these major seven groups of vascular plants. And three of them are considered bryophytes even though it's not a monophyletic group. They're a grade of lineages, the mosses, hornworts and liverworts that I mentioned that have a subset of the features, subset of the adaptations to land that we see in the vascular plants but not all of them. And the main things that we focused on as far as the freshwater green algae. Remember they, even though the sea lettuce which is a marine alga has that alternation of generations, the closest relatives of land plants do not have an alternation of generations. They're only diploid phases as I go. So they just have a, essentially they just have a gametophyte. They just have a haploid phase. And then we see the interjection of a sporophyte in the bryophytes. So these do have a sporophyte but it's highly reduced. But the main plant body is haploid. It's a gametophyte. And so based on this relationship here, the fact that this is paraphyletic relative to the vascular plants, it makes it clear that the features shared by these taxa were ancestral for all land plants. Okay so the bryophytes provide us with some real clues to what the original land plant was like. And the features these lineages share was likely ancestral. So the gametophyte being dominant and the sporophyte being just parasitic and connected to the gametophyte throughout its life, that seems to have been ancestral in the land plants. And these are free sporing plants. These are not seed plants. Remember the seed plants are only down here. And here we have the moss life cycle. So again we have a haploid phase and a diploid phase. But this diploid phase, even though this makes it look fairly extensive, it's just this parasitic, very highly, very minor organism that's parasitic on the photosynthetic gametophyte by this foot here. It's just basically a sporangium on a stalk. So it's pretty minimal as far as an organism goes. It's just a multicellular organism and it's genetically distinct from this gametophyte. Okay so that's the moss life cycle. Are there questions about bryophytes? Yeah I'm going to get to that in just a minute. But it's a worthwhile point to make here too. It's good that you said that because in this particular example from the book, you can see that there is, in this case we have two different types of gametophytes, a female gametophyte and a male gametophyte. Some mosses do show that sort of differentiation between their gametophytes where they have male and female gametophytes. But the spore sizes remain the same and they don't have distinctive sporangia that produce a mega spore that germinates to be the female gametophyte and a smaller micro spore that germinates to be the male gametophyte. So that concept of heterospery is generally discussed only in the context of vascular plants, not the bryophytes. But nonetheless one of the main distinctions between heterosperous and homosperous vascular plants is that in heterosperous vascular plants you have unisexual gametophytes, you have male gametophytes that produce sperm and you have female gametophytes that produce eggs. You don't have bisexual gametophytes that produce both. Okay, so that's, and that's going on here in this particular moss, but some mosses do it this way and some mosses have bisexual gametophytes. Here they can be to some extent, yeah, so that can be true in bryophytes. It's a relatively minor amount of photosynthate they produce compared to what the gametophytes produce. But yeah, that's true. In fact, some of them have stomata. So there are some bryophytes, not liverworts, but there are some sporophytes of mosses and hornworts that produce stomata. So that's an interesting situation too. Sorry. Oh no, not the dates, but it should, one thing that's important to point out though is that it's clear that the bryophytes, basically the bryophyte lineage follows this, if you follow the main backbone of this land plant phylogeny, the bryophytes are early branching here, so the organisms that existed through this part of the tree would have shared the features that all of these three groups have. So the bryophyte biology was in place here prior to the vascular plant biology, the distinguishing features of the vascular plants. So the sporophyte dominance doesn't come into play until after somewhere along this branch. Remember, I did point out that there are some fossil vascular plants that would be somewhere along this branch that have isomorphic alternation and generations where the gametophyte and the sporophyte look the same. So there's a transitional fossil between gametophyte dominance and sporophyte dominance, but none of those plants are still extant. They're way back in the paleozoic. All right, and this is just, you saw this earlier. This is just reiterating the point that I already made that the land plants have both multicellular haploid and diploid generations, whereas that's not true for fungi and animals. They have one or the other. Okay, then we got into the vascular plants. The fern life cycle is the first one we talked about. And in thinking about all of this, you should also be, as you go through the notes, think about the features that we see coming into place within the land plant phylogeny that have potential value for life on land. So things like acutical, and I'll go through some of those in a minute, but just I want to make that point now since we're getting into land plants more that this theme of life on land, keep that in mind as you're studying. And there's a diagram I'll show you in a minute that's helpful with regard to that. But the fern life cycle then is the first one we looked at where the sporophyte is dominant. And I spent a little time talking about the fern morphology. So remember in ferns, the aerial part, the part that's actually above ground is usually just the leaves. And the main part of the plant underground is the stem and the roots. So the stems are typically horizontal except in the tree ferns, which are pretty minor group overall in terms of diversity. And also we talked about how the sporangia are born on these undersides of the leaves in these structures called sorai that are clusters of sporangia and then the sporangia then produce spores. So I want you to be able to keep in mind the scale here in terms of what the spores are inside sporangia, sporangia are inside sorai on the leaves. I mean, you should have some sense of the overall scale or the size of these things relative to one another that's sort of a basic point, but I know it's easy to get confused about what's a spore, what's a sporangium, but the sporangium is a multicellular sac that bears spores. As a gametangium is a multicellular sac that bears gametes on the gametophyte and there are two different types of gametangia. So the antheridium that produces sperm and the archegonium that produces eggs. I mean, that's some basic terminology that applies across these groups that you should be aware of and should be familiar with. And something like sorai, that's a significant enough feature that I would expect you to remember that. But, you know, there's a lot of this terminology comes up again and again. There's a little bit of specific terminology in the ferns that I think, you know, that I focused on that's worth remembering. Questions about ferns? Yeah. Oh, rhizoids. Well, they can serve to anchor a plant to their substrate. They're not so functional in absorption as a root. Roots come into play. That's one of the things mentioned in terms of adaptations to land. In the vascular plants, we have the evolution of roots. We don't see those in the bryophytes, we just have rhizoids. And in the fern gametophyte, we have rhizoids too, but not in the sporophyte. But yeah, they mainly have an anchorage function, not so much an absorption function. The gametophytes can absorb moisture right through the main body, the thallus, as in a bryophyte. So here's heterospery again. And this occurs, remember, in the lycophytes. And some of them, that's what this is, is lycophyte cone from the salagenella, where you can see megaspores on the left and microspores on the right in a microsperangium and a megasporangium. So again, these are spores produced by meiosis from the sporophyte, but it just so happens the sporophyte produces two different types of spores in different sporangia. And these germinate to be female gametophytes, these germinate to be male gametophytes. So we have a separation of function here, less chance for sulfane. And in all these organisms that have this unisexual gametophyte, you have germination, or you have the multicellular gametophyte living within the confines of the spore wall. So they can't emerge to some extent like the pollen tube that grows out in the case of seed plants. The pollen emerges as a tube, but for the most part there's containment within this spore wall for a long period of time. So the heterosperous organisms, which include some lycophytes, a very small number of ferns, which we didn't focus on at all, so it's not really important to remember, but the water ferns and all of the seed plants, all the seed plants are heterosperous. In those we get this development within the spore to some extent. So there are questions about heterospery then. Yeah, no they don't. They don't all have strobolyte, but the ones that we talked about do, because we just really the only heterosperous plants we really focused on much were in the seed plants. I did mention selaginella in the lycophytes, these moss-like plants, which this is, and this does have a strobolyte, but there's something called quillwort, so we didn't get into these isoides that don't have strobolyte, and they actually have the largest of all megaspores. You can see them with your naked eye pretty well, but yeah, oftentimes you do have, generally you have strobolyte or cones. So seed plants then, so in the case of, we went into the pine life cycle, an example of a gymnast sperm life cycle. So remember, we're seeing this trend in the land plants, that's basically, at least in the way that we've looked at these groups. We're seeing progressive reduction of the gametophyte generation and increasing dominance of the sporophyte generation. And in the case of the seed plants then, the gametophytes represent the pollen, in the case of the male gametophyte, so the pollen is the male gametophyte, and it's dispersed in an immature stage, but it's already undergone at least one mitotic division before it's dispersed from the microsperangia or the pollen sacs. And then the megagametophyte, remember, is contained within the ovule. So the ovule, the immature seed, is the home of the female gametophyte and it never leaves that site. So it's never shed from the megasporangium, which is also contained within the ovule. The ovule, when it's early a stage, remember, is just a megasporangium with integument around it, which is a novel structure that becomes the seed coat. It doesn't have a homolog in the early, that we're clear about at least in these other, in the non-seed plants. And went through the stages of pollination and fertilization in the conifer, in the pine. So remember, pollination in the gymnasperms means the pollen is actually landing at the micropiler opening into the ovule. This is different, remember, than in flowering plants. We'll get to back in a minute. But here, pollination means the pollen has to arrive at the ovule itself. So right at the doorstep of the female gametophyte, so it has to get to this point into the pollen chamber and then the pollen tube germinates, more mitotic division, and grows down to the egg inside the archegonium. And then we ultimately have germination, or we have, sorry, we have the fertilization of the egg. And remember, there's just one fertilization event in the conifers, in the seed, in the pines. And then we ultimately get the embryo developing inside here. So remember, there are embryos in all of the land plants. It's in the seed plants where the embryo has this long dormant phase or long inactive phase where the seed becomes desiccated. And remember, I mentioned in the last lecture that ABA, abscissic acid, is involved in preparing the seed for that. But in any case, we have three generations of tissue here. We've got the original parent sporophyte, the diploid tissue on the outside. We have the haploid female gametophyte tissue. That's the nutritive tissue for the embryo, which is the next generation of diploid sporophyte. So diploid, haploid, diploid. Three generations of tissue there in the pine. So there are questions about this. This doesn't require freestanding water. We have very much more sheltering of the gametophytes from the environment. And we have a lot of protection provided now to the female gametophyte and to the subsequent sporophyte generation as well as dispersal protection during dispersal from the parent sporophyte. Okay, any questions about that? So now to the flowering plants. So remember, the flowering plants on the flower is basically a strobalus or a cone. And one of the most important features of the flowering plants differentiating them from the gymnisperms is the carpal or the presence of a pistol comprised of one or more carpals, which are basically leaves that have fused along their margin to produce a chamber in which the ovules are contained. So the ovules are protected from the environment. Pollination involves germination of the pollen away from the ovules on the stigma. And then we have a lot more female selectivity here in terms of, or at least parental selectivity on the part of the parent of these female gametophytes with regard to pollen parent of those gametophyte. A male mate for these female gametophytes and also competition between the males here growing down through the style. Okay, so that's one of the main things I want to mention about. And remember the carpal develops, or the pistol or the carpal develops into fruit, which is another important feature of angiosperms in terms of dispersal, mature ovary, and sometimes other parts, accessory tissues of one or more flowers becomes a dispersal unit oftentimes. All right, and I just mentioned then pollination in flowering plants involving in some sort of attractant or advertisement. So remember, pollination involves minimally an attractant or an advertisement for pollinator if it's animal pollination. There is wind pollination in angiosperms. It's derived from animal pollination. But where we do get biotic or animal pollination, there's an attractant and sometimes there's a reward, but not always. I talked about deceit pollination with fly pollination and the be orchids and there's some other examples too, but usually there's a reward of some kind. And remember, I spent some time talking about different pollination syndromes where there seems to have been co-evolution or at least evolution on the side of the plant with regard to different kinds of pollinators. So you should study those two, those pollination syndromes, for example, like fly pollination, bee pollination, that sort of thing. Questions on any of that? All right, and then again, the male gametophyte and female gametophyte even becoming more reduced in the flowering plants than in the conifers. So the pollen of angiosperms, flowering plants, is only comprised of two cells at the time of dispersal and then later the generative cell undergoes mitosis to give rise to two sperms. So we just have the bare minimum number of cells to make this thing work as an organism to grow the pollen tube and to fertilize both the egg and the other sperm member fuses with the two polar nuclei of the female gametophyte that become the endosperm, the nutritive tissue. So the angiosperms wait to invest in their nutritive tissue until after fertilization has happened. So that's probably a very important innovation in terms of conserving resources until they're needed. Oh, that's the point about reward and pollination. And again, the female gametophyte highly reduced by comparison with the conifer or the pine female gametophyte. Just a few cells, typically about seven and eight nuclei. Again, those two polar nuclei here undergo fusion with one of the sperm to produce the endosperm mother cell that goes on to undergo mitosis to give rise to triploid. And this is triploid tissue, not diploid or haploid, but 3N because two nuclei of the female gametophyte fused with one of the sperms. So you get three genomes together here. And that nourishes the zygote and the developing embryo. So this double fertilization process is thought to be another really important innovation of the flowering plants in terms of waiting to produce the nutritive tissue until after fertilization. Okay, so then I also talked a little bit about fruits. So do study those fruit types. Talked about those different fruit types. And also talked about, so yeah, I mean, there were various types of dispersal. We talked about involving seeds or whole fruits or plants, both abiotic and biotic, both by animal and by physical forces. And I also talked about mechanisms against selfing in flowering plants. I don't have a slide here to show you that, but remember we talked about things like spatial separation of the stigma and the stamens, differential timing of maturation of stamens and pistols, unisexual, evolution of unisexual, or I should say evolution of pistolate function occurring on only one sporophyte and staminate function on another sporophyte, the dioecious condition. Things like that, we make sure to review those important features in terms of minimizing self-pollination, self-fertilization. And this is that figure that I mentioned that shows some of the important changes we see in the land plants. So here we have the bryophytes again. And here are the vascular plants. And here are the flowering plants. So again, the alternation of generations is something all the land plants share. But after the land plants diverge from the green algae, the closest freshwater green algae here, we have gametangia evolving. So archegonia and antheridia, we actually have embryos evolved. So these are all called the embryophytes. That's another name for all the land plants. And remember the true vascular tissue evolved in the sporophytes of the vascular plants. We don't get true vascular tissue in the bryophytes. True roots evolve in the true vascular plants. The bryophytes don't have true roots. And as I mentioned, there is heteroaspir that evolved in other places other than just in the seed plants. But the seed plants evolved from heteroaspirous ancestors. And we have this reduction in the gametophytes eventually resulting in the loss of the antheridia. The pollen doesn't have antheridia. And in the flowering plants, we've even lost the archegonium and we have double fertilization. The carpal here and the evolution of fruit. So that just reiterates some other points already made. Okay, so other things to study. We get into structure here. So you should be aware of the distinction between determinate and indeterminate growth. So stems and roots undergo indeterminate growth. And they have growth from the apical meristem, primary growth that results in lengthening both the apical meristem of the shoot as well as the roots. But leaves have determinate growth. Typically, the meristems and leaves last only a brief time until the leaf is fully formed. And the same goes with the flower. Remember, a flower is a determinate shoot after the pistols are formed. It doesn't continue to develop. It terminates. But indeterminate growth is this whole, what we see, which is so different from animals where have these tissues that continue to be, you know, these growing points that continue to develop. And those include not only apical meristems and primary growth, but lateral meristems and secondary growth of eudaicots, conifers, but not monocots. Remember, monocots don't have secondary growth. So be aware of both types of lateral meristems, the vascular cambium and the cork cambium that are both resulting in thickening growth, increasing the amount of vascular tissue in the case of the vascular cambium, increasing the amount of dermal tissue in the case of the cork cambium. Okay, we don't have much time left. So review cell types and tissue systems. There are just a few of each. And be familiar with those. We've talked about parenchyma, chalenchyma, sclerenchyma, vascular tissue, of which we have a couple of types, phloem and xylem. And those cell types. Modified structures, they talked about, you know, modified roots, modified stems, modified leaves. You should be familiar with those and be able to say which is a leaf, which is a stem, which is a root. And again, the types of meristems, lateral meristems. For example, some of the consequences of secondary growth in terms of, you know, this thickening growth and what there are some slides that have to do with that. I talked about nutrients briefly. So mobile versus immobile nutrients. I'm not expecting you to memorize all of the different macro and micronutrients, but realize there are macronutrients and micronutrients. The casperian strip here in the endodermis and its importance for serving as a barrier to movement from the soil, a movement of solutes and substances from the soil into the vascular tissue. I talked quite a bit about this. Also talked about, well, we already talked about mycorrhizal. We talked about water potential and the importance of water potential in terms of movement of water, free energy of water. So water goes from high water potential to low water potential. It's going to talk about osmosis, very similar principles, and how water is transported in the xylem versus the phloem, remember? It's negative pressure basically that's pulling the water up, whereas here we have positive pressure pushing the phloem through the sieve tubes. So differences between passive active transport versus bulk flow. Remember passive and active transport is movement across a membrane. Bulk flow is not movement within tubes, and we have these two different types here. In photoperiodism, I talked quite a bit about that. So be aware about photoperiodism. You should be familiar with what a short day and what a long day plan are responding to in terms of stimuli to flower. So I have a general understanding also of hormone action. So I talked about the importance of dosage in hormones, the importance of how they can have differential effects on different tissues or tissues of different ages, or the dosage can result in a different effect, and that the balance of hormones is really important. So those were some major points. And also, finally, the major differences between the hormones and their primary action. So I had a list of different types of hormones, and some of the things that those hormones are most important in terms of what kinds of responses they tend to signal. So are there any last questions? But office hours, I'm going to continue to hold them through up to the day of the final. So just come when you can if you have additional questions.