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survivingcollegeonefanficatatime · 1 year ago

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biology 1

star wars, uneddited, tehnically spell checked but only in the sense I spamed 'accept' on every spelling error correction.

Ashoka groaned, she dropped her into her hands in frustration. She was tired, and felt like everything was going wrong. She had an exam coming up, and she just couldn’t get everything to stick in her memory. She was a jedi in training! She was supposed to be good at this sort of thing! She just…. Struggled with biology, especially the specifics of a single planet's biology. Every day she wondered why she decided to take a class on Naboo’s Organismal Biology. Still, she had to pass this test, she had to.

“Uh Commander?” Fives was sitting next to Ashoka, his voice was concerned. With a huff the padawan looked up at him, she squinted for a moment, before an idea caused her entire being to brighten.

“Wanna help me with something” she replied.

“Help you with what?” there was an edge of wariness in his voice, but Ashoka shrugged it off.

“I’ve gotta pass this stupid biology exam, and I’m not making any progress on my own and-” she hesitated for just a moment “Master Obi-Wan always says that the best way to ensure you understand a subject is to teach it to someone else.”

“Uh, so you want to teach me biology, commander?”

“Yes!”

Fives blinked in surprise, his head tilted in that way it always did when he was parsing through an idea. Then he smiled and asked “can I invite a few others along?” Ashoka’s answering grin was downright gleeful. She agreed without hesitation.

Fives, Echo, Rex, Jessie, Kix and a few others ended up following Ashoka to a random storage room that she’d haistally converted to, teaching room.

“Alright! So, uh, this class is technically a sequel class to the molecular biology class I just finished, but I think we can start here and be fine. It’s also more of a general biology class, but it has a specific focus on Naboo and its history as an example of how biological systems work on different planets. It’s just easier to start with one planet and build from there” Ashoka was nervous, but she was determined to explain this right.

“Alright, so where are we staring?” Kix asked

“Oh, uh the creation of species!” the padawan smiled. “A species is a group of organisms that is divided into a group they share distinctive traits or attributes and are thus separated from other species, it's a little hard because there’s no definitive definition of what a species is, there’s a few different ways to sort it out, but it’s one of those things researchers like to bicker about. First we should probably understand some terms! Speciation is how you form new species, Ation can be defined as an instance of or to denote an action, so Speciation would be ‘the act of creating a new species’ or ‘instance of a species’ most words in biology are simple to understand when you know their root words.” Ashoka took a breath, only for a voice to ask.

“Root words?”

“Oh, yeah, a lot of the sciences are named with terms from a long dead language, we can still translate that language but no one really speaks it the way it was supposed to be spoken.”

“Oh!” Echo called “so if you can translate the parts of the words, you can understand what the term means?”

“Yeah!” Ashoka agreed. She cleared her throat “uh, anyways, evolution, which is sort of the driving force of speciation, it’s the accumulation of changes in a population over time. This can result in speciation but sometimes it’s just evolution. It’s also important to know that it’s made up, mostly, of little changes over time. That’s called microevolution! Over a long period of time, microevolution can become macroevolution. Micro is little, macro is big.”

“So small changes can lead to bigger changes?” Kix called

“Yeah! And there’s a few driving forces behind changes in allele frequency, which is microevolution in work! The first three are based on random chance, they’re non-adaptive, so in other words they just happen. This includes mutation, the thing where an organisms genetics is altered, this is typically neutral or outright harmful, but it can occasionally be helpful, then there’s gene flow, which is what happens when alleles more from one population to another, so like when one population meets with another the final of the three is genetic drift, which most strongly affects small populations, and can lead to the basically random erasure of certain traits if a small population just gets unlucky and all individuals with a specific trait die. It can also be caused by the bottleneck effect! Or from isolation.

“The other type are adaptive, or at the very least nonrandom, this is sexual selection or natural selection, sexual selection is, exactly what the name implies, natural selection is sometimes referred to as survival of the fittest, but I personally feel like that name could be a little better, because while some individuals are more fit, it’s really about which survive to reproduction! Or at the very least can survive long enough to pass down their genes.”

Ashoka took a breath, she flicked to the holo-projector she’d set up, it showed an image of a Nabooian lizard and a feline she didn’t know the name of.

“Alright, so there’s a couple of ways to define what a species is, as I mentioned there’s no one universal definition but here’s a few of the methods researchers use! Morphological species concept is focused on organisms sharing physical traits-” she gestured to the lizard and feline behind her “-these two organisms have visually distinctive traits, so we can look at them and understand they may be different species, it also takes internals into account, anyone know what the flaws of this system is?”

Kix huffed and muttered “a loath wolf and a Pantorean frost wolf look basically the same, and some tooka’s that look like they came from different planets.”

“Yes! Exactly Kix” Ashoka cheered, Kix startled, apparently he hadn’t realized he’d muttered loud enough to be heard, but Ashoka was a predator and had exceptional hearing. She quickly repeated his words to the rest of the clones who nodded in understanding.

“Alright!” she continued “ the next concept is biological, which is more based on reproduction than genetics, we’ll get to the genetics one in a second, where was I?” the padawan looked around for a moment before her eyes widened and she continued “right uhh biological species! This means they can reproduce, different species cannot breed because they’re reproductively isolated.” a hand, someone in the back, shot up before Ashoka could even ask what the limitations were.

“Yes?”

“Twi’leks and humans can reproduce, they’re not the same species”

“That’s true. This is a limitation of the biological species concept”

“Skywalker’s blood work only shows one biological parent, which he insists is not an error.” Kix cut in.

“That’s another limitation of the biological species concept, although Skyguy is an outlier and probably shouldn’t be a reference for this class, but uhh yeah most humanoids can reproduce with each other despite being different species, and some species--although not humans according to everyone except Skyguy--can reproduce asexually, it's important to note that this concept applies to species that would not mate in the wild, so artificial insemination, or intentional breeding by sapients does not count.”

“There’s also the evolutionary lineage, or phylogenetic, which is made of two roots. Does anyone know what they mean?”

“Well,” Kix said “genetics is fairly self explanatory, Phylo means ‘tribe’ ‘kind’ or ‘group’ I guess. So group genetics?”

“Yeah!” Ashoka cheered “do all of you know latin?”

“Echo dose because he as weird interests” Rex called, ignoring his brother’s protests “and Kix dose because he’s a medic”

“Oh that makes sense, there’s a lot of latin in medicine” Ashoka agreed, she got the distinct feeling that the clones were asking and answering her questions mostly for her sake. They probably already knew all this, and were merely humoring her. She shook herself out of the thought before she could get distracted, she had to pass her next exam.

“And next is the ecological species concept--” another hand shot up Ashoka nodded towards it, in a silent indication that the clone should speak.

“Ecology is the environment! I know that one! Does that mean we’re dividing species based on their environments? There’s a buncha species that show up in a lotta environments, most humanoids but I don’t know if they count, they can be in all sortsa environments, and a lotta them are different species.”

“That’s exactly right, this one is mostly used for bacterial species, but it can be useful, bacteria are annoying to categorize, for a number of reasons so this one can help, but like you said, sometimes species can handle a wide variety of environments, and sometimes different species hangout in the same niche, this one’s more about niches”

“Alright the last one is the general lineage concept, this one frames each species as a population of an evolving lineage, so it’s focus is on history and how traits evolved, this one is kinda like an ‘all of the above’ option so it has the evolutionary relationships, reproductive isolation, avatar requirements and other elements of the others, it, like every other concept is flawed but I think this one makes the most sense. Especially when looking at the story of how things evolved.'' There were nodes around the room. Ashoka gestured to the holo-projector, causing it to display a chart.

“There’s a few types of reproductive isolation, prezygotic which is the prevention of a zygote, and postzygotic which happens post creation of a zygote. I’ll say the concepts and we’ll sort them after”

“Habitat isolation?”

“Prezygotic!”

“Temporal--time, isolation”

“Prezygotic!”

“Behavioral isolation”

Prezygotic!”

“Mechanical isolation”

“... prezygotic?”

“Yup! And gametic isolation?”

“That’s when the gammates don’t line up, wouldn’t that be mechanical isolation?”

“Good question, it’s different because in this one, there is no mechanical problem, the sperm and egg can get to each other, but they don’t fuze”

“So, postzygotic? Because it’s after uhh- an- er- attempt at fertilization?”

“Not quite” Ashoka explained “zygote formation happens as a result of fertilization, not from an attempt at it. So this prevents the formation of a zygote. That makes it prezygotic!” Ashoka took a breath “there’s three more, Hybrid inviability, hybrid infertility or sterility and hybrid breakdown any guesses on those three”

“They’re all postzygotic because a hybrid can form”

“And they’re names are fairly self explanatory!” Ashoka agreed. Her smile was bright, and the room was alight with curiosity and a mumble of excitement that radiated from her men. “So now we go onto how new species arise! I already mentioned speciation, but a more specific term is Cladogenesis'' this time she expected Echo’s hand to shoot up.

“Clado means branch, and genesis is creation, so the creation of a branch, oh that’s why it’s more specific, because it’s the creation of a specific branch, not just the process through which species are created!” he smiled, and the force rang with pride over the answer, Ashoka couldn’t help but beam, maybe she’d pass this exam afterall.

“That’s an amazing answer Echo! I hadn’t even thought of the ‘reason it’s more specific than speciation’ I’d mostly been using the words as synonyms!” Fives clapped echo on the shoulder, there was an undercut of a challenge in the force, and Asoka suddenly knew every man in the room would now be competing to get the best answers.

“Alright, so how can this happen, isolation is one way, geographical isolation can cut off populations from each other, there can be a change in the environment to make this happen this can lead to Allopatric speciation.”

“Allo is separate!” someone called Ashoka could just make out the soft glow of a datapad in his hand. Jessie cut him off before he could continue “patric is noblemen??” he sounded confused

“Close, in this case a more accurate translation would be ‘father’ in this case it means ‘fatherland’ so ‘separate fatherland’ or the creation of new species because of a separation in fatherlands! With that in mind can anyone guess what sympatric speciation means?”

“Is it the creation of new species within the same fatherland? How does that happen?”

“It is, uhh it’d be easier to explain with an example, on Naboo there’s a fruit, an alletic fruit, it was an import from a planet with a similar ecosystem, Naboo had a type of insect, it fet on the native thornfruit population, the alletic trees produce fruit earlier in the year than thornfruit do, so when a handful of the insects hatched early, they discovered the much larger and unclaimed alletic fruit, this gave the early hatching insects an advantage, and overtime the subpopulation of insects started hatching earlier and earlier to line up with the fruiting of the allitic trees, the population of thornfruit bugs who had later hatch times remained consistent, and over time they became two different species!” the clones nodded.

“Does that happen often?” Rex asked.

“It happens most often for plants because they can self fertilize, and hybridize with other species, this can cause extra chromosomes, or polyploidy! In most creatures this is a problem, but plants can sometimes just… do this-'' Ashoka wrinkles her nose “plants are weird. They can do something called autopolyploidy where they can self fertilize and end up with an… extra chromosome set, this is something that wouldn't let the plant fertilize with others, and is… not typically a good thing in non-plants. They can also do allopolyploidy which is with a member of a different species, also weird. Anyways this creates a new species in a single generation which is…. Weird, the last method of sympatric speciation is hybrid speciation, which is a little self explanatory”

Ashoka took a deep breath after the rush of information. She waved away the chart behind her, and instead two sets of images of the feet of two different types of birds during embryonic development.

“Evo-devo is a dumb sounding word but it’s evolutionary development, uhh there’s pattern formation, so if you look at these two developmental bird feet, you’ll see the blue indicates BMP4, and in the next image you’ll notice the levels of gremlin protnes, those proteins aren’t expressed in the feet on one of the images, this is because DMP4 causes cells to undergo programed cell death, and gremlin inhibits the function of BMP4, so-” she waved her hand, behind her the holo-projector changed again, this time showing two bird feet, one with distinctive toes and one with webbed feet- “the one that had high gremlin levels developed webbed feet because the cells did not undergo cell death!”

“Another important aspect of evo-devo, at least for Naboo, is Hox genes, they’re present in all animals, and they’re responsible for body plan, animals with a more complex body plan have more hox genes, and animals with simpler body plans have less hox genes.”

[skip lec 2]

After a short break, everyone had reconvened, and Ashoka decided to take a closer look at the clones who’d shown up. She wanted to make an effort to know who was in the room more than just those she was closest to (or those who were in the front row). There were three rows, although it was more of a group huddle than anything else Rex, Echo, Fives, Jessie, and Kix sat in the front, followed by Dogma, Hardcase, Pebble, and Suture, behind them were Leif, Wraith, Shadow, and Pattern. Ashoka smiled and set up.

“This lecture was a lot, honestly it’s on me for deciding to take an accelerated class in the middle of a war, but here I am, so, time to go over all of life on Naboo in an hour or less!” several clones choked in response to that statement. Ashoka couldn’t help but laugh, her teacher had declared something similar multiple times, although the best was his announcement that they were going to cover every invertible in half an hour. The padawan blamed her nearly manic smile on that memory, before she turned back to her men and asked “ready to start?”

“Sir, yes sir!” the entire room said at once, the force bubbled with amusement and an eager anticipation. She really hadn’t expected her men to enjoy this so much, or for that many of them to even show up.

“The history of Naboo can be set on a geological timescale, something so long it’s often hard for sapients to comprehend it! That said, it’s not quite as long as a cosmic time scale. It's theorized that the formation of life on Naboo was both at a similar time, and formed in a similar way to life elsewhere, that’s why we focus on Naboo in this class, a lot of its history is well documented! Just keep in mind, for this timeline we’re focusing on one planet, so when I say ‘we can divide the timeline into 4 eons’ I’m referring specifically to Naboo.” the clones nodded, and Ashoka continued “as I just mentioned there were four eons, in order they’re the Hadean, the Archean, the Proterozoic, and the Pharneozoic. The first fossil record of life was about 3.5 billion years ago, but we suspect life started before that. This is during the Archean period. When Naboo first formed it was far too hot for liquid water to form, this stage was called the Hadean eon, it was far too hot and too dry for life to form, at the end of this period we have the first oceans.”

Ashoka took a breath, her men were listening intently, but this was a lot of information. She flicked her eyes around the room and suddenly remembered she’d forgotten to put the timeline up on the holo-projector. Ashoka cursed herself and quickly set it up, a visual representation was always useful.

“You can remember the Hadean period because it sounds like Hades, and Hades is the mythical god of the Naboo underworld, I’m not entirely familiar with Naboo’s mythology, but there are several cultures that describe the underworld as hot and unpresent, at least if you’re a so-called ‘bad person'’' Ashoka made air quotes as she finished her statement, as useful as the mnemonic was to remember the eon, that mythology was a far cry form jedi beliefs. She shook herself out of that train of thought and returned to her lecture.

“The period after is the Archaea, and the origin of life, you can remember this one because Archaea, one of the three domains of life, are not currently known to photosynthesise, and Photosynthesis comes at the very end of the Archean and the beginning of the Proterozoic. I remember that eon Zonic reminds me of zygote, and this was before the current eon, and Zygotes are related to birth or creation, so it was before the creation of the current eon'' she trailed off for a moment “don’t ask me why zonic reminds me of zygote I know they don’t sound the same”

The room laughed, amusement danced from clone to clone.

“Lots of important stuff happened in the protozoic, the first cyanobacteria, the first eukaryotes, the first photosynthetic eukaryotes, and multicellular ones, and we get some early fossils of multicellular animals! Finally we have the phanerozoic, which is the current one, it’s still an incomprehensible long time ago, measured in millions of years ago.” Ashoka zoomed in on her timeline, showing the division of the Phanerozoic eon.

“The Paleozoic, mesozoic, and cenozoic are the three eras. As you can see, the paleozoic is the longest, divided into the Cambrian, Ordovician, Sullurian, Devoean, Carboniferous, and Permian.”

“That’s a lot to remember,” Pebble huffed, his face pulled into a grimace. “They’re making you memorize all of this? When’s your exam again?” Ashoka rubbed the back of her head

“Tomorrow….” she mumbled, the entire room burst into noise

“Commander Tano, have you been procrastinating again?” Rex sounded more tired than disappointed, but Ashoka couldn’t help the wince.

“No! No, I mean, this is an accelerated class, so it only takes a week, usually this class would take 14-16 weeks to teach, but with the war I don’t really have time to take classes that long, and they were offering it accelerated…. Technically this is only the second week of class… And I’ve been studying as I go”

“A month?” Fives paled

“Yeah! And I only have until tomorrow and it’s getting late so we’ve gotta get back to it!” There was a wave of determination passed between the clones, and they nodded.

“Right, the Paleozoic has the cambrian, the ordovician, the sullivan, the devonian, the carboniferous, and the permian. The Mesozoic has the triassic, jurassic, and cretaceous, finally the cenozoic has the tertiary and the quaternary.” she huffed a breath.

“In the proterozoic the first colonial cyanobacteria showed up, they have a massive evolutionary advantage, they were once called blue-green algae but that’s not a thing, and also they look green to me but whatever.” Ashoka paused, she knew she was slipping through topics, but she needed to focus on what she didn’t know. She suspected her lecture was going to get more disjointed as she went.

“Um, does anyone know the two strategies that organisms can use to create energy?”

Leif spoke up “they can eat stuff or eat the sun right?”

“Not quite” Ashoka explained “they can be heterotrophic or autotrophic, they can get their energy from chemical bonds in stuff they consume, or harness energy from light or inorganic molecules, so you were close.” Ashoka scrolled through her notes, looking for something she needed to go over. She wanted to go back to the phanerozoic eon, it was the one that had the most she needed to remember. After a bit of scrolling she found the section she wanted.

“Ah- let’s go back to the Phanerozoic, which started 543 million years ago and goes to the present day, we start with the cambrian explosion!” Fives raised his hand.

“I know this one! Or uh I think, that’s when there were a ton of new creatures right?” he asked. Ashoka nodded

“There was a massive increase in the oxygen in the atmosphere and it lead to creatures showing up. I think that one is fairly easy to remember because of the sheer drama of the Cambrian explosion. After that we have the ordovician period, that ordo-like order, and it happened right after an explosion, so chaos leads to order, this is when we get hard-shelled aquatic life and invertebrates. Like trilobites, there were also early land plants and arthropods. This also leads to large glaciers and a mass extinction, those happen sometimes.”

“The silurian period has significant changes in vertebrates and plants but other than that it’s mainly stable, the silurian, like silver, and if there’s a silver lining to a mass extinction it's that there’s an increase in biodiversity afterwards! This is when we have major colonization of the land by creatures. And the eventual creation of seed plants. In the Devonian we got more seed plants and bugs. And some vertebrates are attempting to come on land. I don’t have a good mnemonic for this one…” she huffed, slightly disappointed.

“Dreaded Devonian, aren't humans evolved from creatures that did something similar? Obviously the gungans became semi aquatic rather than fully terrestrial, but if those fish on whatever human homeworld may have existed only stayed in the damn ocean then we wouldn’t be dealing with this mess' ' Suture huffed.

“I don’t know, there are several fully aquatic sapients, we might’ve ended up here anyways.” Hardcase pointed out. Ashoka rolled her eyes.

“The carboniferous period was when coal formed, because of the compressed layers of rotting vegetation, and we have flying insects, big ones, anyone got any guesses as to why they were so large?”

“Oxygen?” Kix cut in suppressing a visible shutter, Ashoka remembered a trip to an oxygen rich planet. She also recalled nearly losing her head to a dragonfly larger than she was. “Oxygen rich planets promote large insects right? It’s cuz’ of how they breathe?”

“Yeah! That’s how I remember this period, it’s the carboniferous period, coal is carbon, and there was a lot more oxygen, so we have a period that’s all about carbon! The permian period includes the largest known mass extinction, on Naboo anyways. This is also wen ferns started getting replaced with gymnosperms, and reptiles started showing up. I think it’s fairly easy to remember this one. This is the end of the Paleozonic. To recap we have the cambrian, the ordovician, the silluran, the devonian, the carboniferous and the permian. Or, going back to the mnemonics the cambrian explosion the order after the explosion: Ordovian which still has a mass extinction, the silver lining siluran, dreaded devonian where fish started to escape, the carboniferous all about carbon and the permian extinction!”

The clones muttered in excitement, bumping against each other as they celebrated getting through the paleozoic.

“Wait, how do you remember paleozoic?” Jessie asked

“Paleo means old, and it’s the oldest of the phanerozoic.” Echo chimed an ‘ooohhh’ rippled through the crowd.

“Next up is the mesozoic, which was a mess.” Ashoka giggled “it’s actually fairly simple to remember, Naboo, like a few other planets had dinosaurs, lots of planets claim to have dinosaurs but none can ever agree what a ‘true dinosaur’ is, Naboo’s dinosaurs include reptiles and birds or aves, so that caused a little drama compared to planets whose so-called dinosaurs were all true ‘lizards’ hence the ‘messy mesozoic’” Ashoka shook her head, younglings of all sorts loved dinosaurs, and debates as to what ‘counted as a dinosaur’ had been a frequent part of her childhood. “The mesozoic had three periods, the triassic, the Jurassic and the cretaceous. The triassic is the first of three hence tri, jurassic is when the dinosaurs became doment on Naboo, and the cretaceous ended in catastrophe with the mass extinction of the dinosaurs.”

“That’s fairly easy to remember” Rex mumbled he had a datapad in his hands, amusement surrounded his force presence but Ashoka suspected he was trying to get other work done during this impromptu class.

“That’s why I like the Mesozoic, '' Ashoka agreed. “Anyways the cenozoic is what Naboo is in right now, divided into the Tertiary and Quaternary, no I don’t know why they’re named after 3 and 4. They just are. It’s easiest to remember because the cenozoic is the current one so if you remember the other three you can remember this as ‘the other one’ and then associate the numbers 3 and 4 with it and bamb cenozoic tertiary quaternary.”

Releaf filled Ashoka, they were getting through the mass of material she’d need to memorize, but there was still so much more to go. She considered, for a moment, jumping ahead, she was weakest with the later lectures but she didn’t want to skip too much. She probably should’ve looked at the exam guide to see just how much from each section was going to be on her exam. She took a deep breath.

“Does anyone remember the three domains of life?” there were only three sections left, they just had a LOT of information, and Ashoka knew she couldn’t skip it.

“Bacteria, archaea, and eukarya” Kix called, before anyone else got a chance to raise their hand.

“Perfect Kix, we’re going to talk about some of them. Bacteria is the farthest from the other two, Archaea and Eukarya diverted more recently in the history of life but they’re still very different. Microorganism is a catch all term for a small organism, it’s not really a class of thing, so much as it’s a description. Archaea and Bacteria are prokaryotic domains. All organisms have cell membranes and ribosomes, semiconservative DNA replication and metabolic pathways. I should probably mention that we’re not really going to talk about virus, right now we’re defining life as ‘has cells’ anything more complicated than that will come in a more advanced class.”

“This isn’t an advanced class?” Ashoka wasn’t sure who’d asked but she shrugged never-the-less

“No, what I’m talking about is all really quite simple, it’s just a lot and even though the class is accelerated that doesn't make it advanced, it’s the second of the introduction to biology classes…” she trailed off for a moment “well, ok, technically this is the second introduction to biology class for those looking into the sciences as a field of specialization.'' There were a few raised eyebrows, Ashoka wasn’t actually going into the sciences, truthfully she wasn’t sure where she wanted to specialize, she was good at mechanics and engineering, but didn’t have anywhere near the level of mathematical ability as her master. She had little patience for politics, despite that being a highly encouraged field, philosophy could be interesting, but she really only had a passing interest. She couldn’t really say why she’d chosen to take these classes other than the fact that they were available and would get her closer to her thesis, which she was supposed to finish before she could be truly eligible for her knight trials. There were exceptions to this rule, but they were hardly common.

Ashoka pulled herself out of her thoughts. “Right um, prokaryotic reproduction!” she exclaimed, glancing down to the page of her notes she’d settled on. “It’s called binary fission and it’s like mitosis but not quite, plasmids are small rings of dna that are related to this, also, they can do horizontal gene transfer which makes them an utter nightmare to track on an evolutionary tree because they just bump into each other and suddenly bamb new dna. Imagen bumping into some random creature and suddenly having some of its DNA in you.” the words had left her in a huff of air, disorganized and scattered. Ashoka took a moment to collect her thoughts and continued.

“Archaea share some features with eukaryotes, which makes sense because they diverged more recently than bacteria, they’re also similar to bacteria, but they’re often extremophiles, and don’t have peptidoglycan in the cell walls. Anyone know what extremophile means?”

“Can you live in dangerous environments?” Pebble asked Ashoka nodded

“That said bacteria can also live in all sorts of places, there’s autotrophs like the photosynthetic cyanobacteria and heterotrophs, some are parasitic, most move and there’s a LOT of phylum. Cyanobacteria and Proteobacteria are important for this exam. They are relevant to eukaryotic cell evolution and the general planet. Cyanobacteria produce oxygen and participate in nitrogen fixation, where as proteobacteria are gram negative. They have a high metabolic diversity, and are useful in a lot of medicine.”

Suture didn’t bother to wait to be called on “is that the group bacta comes from?” Ashoka squinted

“Um, I don’t know, maybe? we’re focusing on Naboo biology and I’m still a little confused on the taxonomy of galaxy at large compared to that of Naboo alon.? I’ll look it up for you after my exam. Anyways proteobacteria are the largest group of bacteria and they’re nitrogen fixing, super important to the global nitrogen cycle of Naboo, Gammaproteobacteria can destroy methane, deltaproteobacteria include sulfate reducing bacteria, and epsilonproteobacteria are important to the global sulfur cycle, so gamma, delta, epsilon, methane, sulfate, sulfur. Bacteria can live in a lot of conditions, some can from akinetes. These are thick walled food storage cells.”

“Like those little rodents who store excess food during winter?” Fives asked.

“Yeah like those, only it’s a cell not a hole under a tree. There are also endospores which are like an escape pod, they put important stuff in the endospores and then they can recover from it afterwards. There's 5 common shapes of bacteria, Cocci are spheres, which you can remember because the C and O both make circular shapes, then there’s Bacilli which are elongated rods, the L’s and I’s remind me of the rod-shapes, Vibrios are comma shaped cells, I don’t have a mnemonic for them, nor do I really have one for Spirochaetes--flexible spiral cells, but Spirilla are rigid spiral cells, so if I remember that the S’s are spirals, an the spirilla are not the springs despite the word looking more like a ‘spring’ then I think I can do it.”

“And then Vibrios are the ‘other ones’ like before when we were covering time.” Echo mumbled.

“Yeah, that’s a good idea. Gram positive cells are blue or purple, and gram negative are usually pink or red, they have a thin peptidoglycan surrounded by a membrane, negative means the dye can’t stick, so it’s got a warrior." With a sigh Ashoka turned the page to the next set of notes. She was beginning to feel exhausted going over so much information in so little time. Still she took a deep breath and continued.

“Protists were the first eukaryotes, they’re most abundant in moist habitats and most are microscopic, they make about half of Naboo’s oxygen, they're the reason for the oil deposits under Naboo’s oceans and are a food source for marine and freshwater animals. Some are parasites but not all. We can divide them into protozoa, algae and fungus-like protists, the Algae are usually photoautotrophic and they produce organic compounds and oxygen, protozoa are heterotrophic and absorb small organic molecules and ingest prey, and the fungus like protists have bodies and reproduction similar to fungi. Protests are labeled based on movement, or motility, Flagellates use Flagella to swim. Flagella are long tentacle-like things at the end of the cell. Ciliates use Cilia, most of these names are self explanatory, although Amebae are less so, they extend lobes or pseudopodia to move. Echo do you know the roots for pseudopodia''

“Pseudo is fake or false, and pod is foot.”

“That’s right, protists can also be classified based on their habitats, planktonic, are aquatic photosynthetic and nutrient pollution can cause red tides. Then there’s periphytic protists which attach themselves to rocks and stands and stuff, this is what makes stocks on the shore slippery. Seaweed are also protists, also called macroalgae; they're large photosynthetic protists.”

“Protists seem complicated,” someone complained.

“They are, and there’s more too” groans filled the room, but Ashoka plowed on. “Well, more accurately we’re covering the Eukaryotic supergroups, which include protists and related plant, animal, and fungal kingdoms, so we’re going over that now.”

“More classifications,” Pebble groaned.

“Unfortunately that’s basically this entire class, so the first we’re going over is Excavata, which is an early eukaryote. You can tell it’s an Excatate because it has a feeding groove, and to excavate something is to dig a hole. Then there’s land plants and related algae which are daily easy to remember because they’re mostly colored algae. They’re very diverse. Alveolata is named for its alveoli, and dinoflagellates are aquatic, they’re the ones who form red tides, and have endosymbiosis with invertebrates, dino like dinosaurs, and they cause red tides, so danger! Dinosaurs are dangerous, hence dinoflagellates making red tides.”

“Like blood!” Fives agreed, Ashoka nodded, a serious expression on her face. The room laughed.

“Apicomplexans are parasite, remember them because they can cause diseases, and diseases are complex, I do, unfortunately need to remember the life cycle of Plasmodium, as an example we talked about Space Flu, which are spread on the Naboo brown fly, it needs two organisms to spread the flu, the plasmodium enters a humanoids blood when bitten by a brown fly, then they enter the liver, where they hide in liver cells, they can do this because the liver of most humanoids has immune privilege so the immune system can’t really look inside, because if it could then the immune system would try to kill the liver, and that’s an autoimmune disorder. They undergo mitosis, and leave as merozoites, because they make you miserable, so they move into red blood cells, and multiply until the cell bursts, which is bad. After that another brownfly will bite the humanoid and the cametocyes will enter the fly, where the gametes will fertilize, become a zygote, undergo meiosis and the cycle will start again.

“The process goes, Sporozoites, because they’re like spores--they travel outside the body, then the Merozities, which make people miserable, from there they become gametocytes, because they make gametes and then it’s back around the loop.”

Kix sighed “why does every planet seem to have some biting insect that can transfer blood-borne diseases?”

“Because the galaxy is a cruel, cruel place” Rex shot back.

“Endosymbiosis!” Ashoka declared, pulling the two out of their banter.

“Endo is inside, and symbiosis is when two organisms work together” Echo called, cutting Kix off before he could interject. The medic shot Echo a look, the ARC in question just smirked.

“That’s right Echo, primary Endosymbiosis, is when a eukaryotic cell consumes a prokaryotic cell, and secondary is when a eukaryotic cell consumes a eukaryotic cell, my teacher described this as keeping another cell as a pet, the larger cell uses the smaller cell for something, and in exchange the smaller cell gets everything it needs. This is the basic idea of how cells get mitochondria, chloroplasts, and midichlorians--”

“Wait midichlorians?” Rex asked. “I thou-”

“Don’t worry about it.” Ashoka cut in.

“No, no, wait, I thought this was just life on Naboo, how are we involving mitochondria and stuff pretty much everyone has?” Suture asked.

Ashoka huffed “we focus on how Naboo developed life, but we’re using it as a jumping off point for the rest of biological systems, it’s easiest to use one planet as an example, so we can learn the structure of the field. Endosymbiosis is a nearly universal trait in life, this is the same for Naboo.” understanding washed across the room, several cones nodded.

“Back to categorization” Ashoka announced

“I’d forgotten we were talking about that, '' Fives admitted, causing the padawan to roll her eyes.

“Stramenopila, they’ve got some algae, fungus like protists, and protozoa. They’re named for the straw-like hairs on their flagella, which is what the name translates to. Brown algae or kelp are marine, they can make entire forests, and bind to rocks with alginic acid. Which is widely used around the galaxy. Diatoms are where the oil deposits on Naboo come from. They also have silicone dioxide in their cell walls, does anyone know what that means?”

“Silicon dioxide… sand right? I believe glass, real glass can be made from that.” Leif says. Ashoka nodded

“Rhizera have some flagellates with some hair-like extensions from their cytoplasm which are filose pseudopodia.”

“So thread-like fake feet?” Kix asked

“Well, more like limbs in this case but yeah!” Asoka agreed, her smile was bright as she moved on “Amoebozoa, those are the ones that can move with pseudopodia, and have ameba and slime molds. Opisthokonta are a part of the animals and fungi kingdoms, as well as related protists, these are the closest living relatives of animals” Ashoka took another moment to breath, she was starting to truly feel exhausted. She shook herself out of it, and announced another break. She only had three sections left, but it was starting to wear on her.

Ashoka hadn’t bothered to leave the impromptu lecture hall, instead she’d merely flopped down and closed her eyes until everyone started to filter back in. she really hoped this would be enough to save her grade tomorrow. It wasn’t that everything was complicated, it was really simple to understand, there was just a LOT of memorization, and that was never something she was partuarally skilled at. Ashoka groaned, she was much better at concepts than she was at remembering lists. How Barris managed to be so good at memorization wasn’t something she would ever understand. The padawan laughed under her breath. Barris would make a good biologist, or healer; her skills at memorization would serve her well if she ever decided to become a Jedi healer.

“Are you doing ok commander?” Rex’s voice surprised her, he’d been the first to return.

“Yeah, this is just a lot, and I don’t wanna fail my exam tomorrow.” she sighed and rubbed her hands down her face.

“From what I can tell you’re doing pretty good. I’ll admit you’ve jumped from topic to topic a few times, and some of this is utterly lost on me, but you’re a good teacher.”

“You think so? Honestly I kinda thought everyone was humoring me.” Ashoka admitted

“You think we were taught this kind of biology? I mean we were taught enough to understand the basics, but we never went in depth, the medics might have, but I don’t know.”

“I’m glad this is interesting.” Ashoka smiled, by now the rest of the men had shuffled in. Ashoka basked in the warmth they radiated through the force. She took one last deep, calming breath, and rolled to her feet.

“The animal kingdom is monophyletic, so they include the common ancestor of animals, and all their descendants. From this we can organize them into a chart. Starting at the common ancestor of animals, they gain multicellularity and two germ layers. Animals are typically divided by body symmetry, germ layers and the way they develop embryonically. There are the bilateral which are bilaterally symmetric, and the others, the first of the others is the ctenophora--comb jellies. They gained a mestre some so their triploblastic. Then we have the porifera, they’re not symmetric, and they have lost germ layers, they’re also made up of cells sorta stuck together rather than tissues, they are extremely simple and very old. Then there’s the true jellies the cnidaria, they’re distinct because like the comb jellies they're radially symmetric, but they also have specialized stinging cells and they’re diploblastic, they have two germ layers. After those three are the bilateral, which have bilateral symmetric, with one exception but that’s an evolutionary regression they’re also triploblastic, or they have three germ layers.

These form when a diploid zygote undergoes cleavage and makes a blastula, part of this blastula makes a little divided, and makes a gastrula containing layers called germ layers.The biladerla can be divided into the prostostromia and the deuterostome. Wanna translate Kix?”

“Mouth first and mouth second?”

“Yeah, this is because of how they develop in the embryo, the blastopore is a pore form during development, in poststomes you have determinate cleavage, if you cut the embryo the broken off part won’t form another organism, they also have spiral cleavage where they layer into a spiral in the dustersomes there’s indeterminate cleavage, so if you split the embryo early on you can get two fully developed organisms. Identical twins can only form in deuterostomes. To explain the mouth thing because in protostomes the blastopore becomes the mouth, hence mouth first, and in deuterostomes the blastopore becomes the anus.” Ashoka’s smile turned down right mischievous “most patients are deuterostomes, in Naboo and beyond. This includes humans and humanoids.” amusement danced in the force, and several grins spread their way across the faces of Ashoka’s men.

“We can also identify animals based on the structure of the body. A coelom is a fluid filled cavity in the dobby, and coelomates have a true coelom, it’s completely lined with the mesoderm. Pseudocoelomates have a fluid filled cavity but it’s not entirely lined in tissue and acoelomates don’t have a cavity, it's cells all the way down! Any ideas why this might be useful or what this might do.”

“Uhh, well a creature would be less dense if they have a cavity right?” Leif asked.

“And they might be more flexible, with one, or at least more able to move, commander, can you elaborate on the difference between pseudocoelomates and coelomates?” Pebble asked

“Oh yeah, um, in true coelomates they have both ends of the coelom coated, so they can cover organs and stuff.”

“So it can offer more protection too?” Jessie asked.

“Yeah! Those are all good answers.” satisfaction passed though the force. “Another criteria is segmentation, any guesses as to how that works or why it’s useful.”

“Well it divides the animal into segments, clearly” Hardcase said.

“Maybe they can repeat body plans?” Fives added.

“Or customize segments?” Kix added. Ashoka smiled and nodded.

“Yeah! So those are methods of classifying animals, now we move on to actually looking at the different animals, comb jellies, or ctenophora are considered the earliest diverging animal lineage! They’re all aquatic, they have two long tentacles and lack stinging cells. True Naboo jellies have stinging cells, but these don’t hence, the different lineage. They also lack Hox genes, this is significant because I said earlier that all animals have hox genes, the thing about biology is that there’s an exception to practically every rule, so we learn rules that are generalizations more than rules, because at this level it’s easiest to explain the rules and the exceptions rather than to remember each instance that follows the rule. If that makes sense?”

The clones nodded and ashoka continued “I mentioned that sponges are old and simple, which is true, most are asthmatic and the adults don’t move. They’ve got sharp spicules--like spikes--and can produce some toxins. They reproduce sexually and asexually. The Cnidaria are Naboo true jellies, they’re diploblastic and radially symmetric. They have stinging cells, polyps are sessile and free swimming medusas are motile. Lophotrochozoa are part bilateral, prostosoms so they are formed mouth first and are bilaterally symmetric, they’re a diverse group, and they’re daily easy to remember because the lophotrochozoa have either a lophore or a trophopre which is basically a bunch of feeding tendrils. They also include platyhelminthes which are flatworms, flatworms are very cute, they’ve got two little eyespots and are…. Well, flatworms. They’re small because they're ancolomes so they can’t get too big. Ecdysozoa have a cuticle which is a structure like an exoskeleton it supports and protects the animal, they’ve got buncha appendages, and include bugs. The curitcal means they need to have internal fertilization. Nematodes are roundworms. Quite a few of these are parasitic, but all roundworms have a bad reputation. Not all are parasites.”

“This is one of the longest segments, we’re almost done with this whole thing, unfortunately these last sections are the longest.” Ashoka explained, she couldn't help but let out a yawn, before she refocused and continued “arthropods are one of the most successful groups in the galaxy. On Naboo alone they make up 75% of the species we know about. They’ve got an exoskeleton, segmented limbs, and cephalization which is when you move your sensory organs to one side of your body, like for example, in the head. They also have a complete digestive system. This group doesn't have blood, not exactly, instead they have an open circulatory system where blood is mixed with other body fluids creating hemolymph. Remember when we were talking about large bugs? This is because the cuticle prevents gasses from diffusing, so they need to be small to get oxygen throughout their bodies, in oxygen rich environments well… they have more access to oxygen so they can afford to get larger without suffocating.”

Kix nodded, Fives’ eyes had glazed over, and he blinked a few times trying to refocus on the topic, he was far from the only one.

“Chelicerata are spiders and others, they’ve got two major segments, so they can’t really turn their heads without turning part of their bodies. They also have 4 pairs of walking legs, hence eight legs. Oh and they have fangs. Myriapoda are millipedes and centipedes, because they have a myriad of legs, millipedes have two pairs of walking legs per segment, they move slow and eat plants whereas centipedes only have one walking leg pair per segment their predators--like me--and move fast; hexapods have three segments, three pairs of walking legs, anre are insects. They live on restoril environments. Oh and they have wings. Insects have separate sexes, they use internal fertilization, and most have complete metamorphosis, does anyone know what that is?”

Leif smiled before answering “yeah that’s the thing where they look totally different as adults compared to babies, it’s like egg, worm, craigslist, adult right?”

“Yes and no, it is when they look different, but it’s egg larba, pupa, adult. Some insects do incomplete metamorphosis, which only has three stages: eggs, nymphs and adults; they look like smaller adults as babies. There’s also crustacea which are crabs and such, they’ve got antennae--two of them, and have to molt.

“Deuterstomia have echinoderms and chordates, the first is aquatic stars urchins and cucumbers. The second is all invertebrates and a few invertebrates. Stars are radially symmetric, but that’s an evolutionary regression, they were bilaterally symmetrical and went back to a previous trait, as babies they’re bilaterally symmetric and as adults they’re radially symmetric. They can also regenerate from parts broken off. They have endoskeletons and water vascular systems. Chordates have a notochord which is a flexible rod between the digestive tract and nervous system. And a hollow dorsal nerve cord, pharyngeal slits, and a postanal tail. Anyone know what Chordate means?”

“String I think” Kix announced.

“Yeah, like a spinal cord.” Ashoka’s words were light. “The basic chordate body plan kinda looks like a weird teardrop, and there are groups within them, like the lancelets which are basically tubes that hangout underground and stick out a little bit, there are also tunicates which are larger tubes, if the lancelets were sticks the tunicates are full circles.'' There was laughter in the air. Ashoka double checked her notes and sighed in relief, there was only one section left. The vertebrates. She was almost done.

“Alright! Last section” she announced with glee “the vertebrates, we’re gonna focus on the chordate clades. If you remember they have a notochord, which is an early version of a backbone, a nerve cord, and a post-anal tail, they also have pharyngeal gill slits. Vertebrates retain the chordate characteristics but modify them. With a vertebral column, a cranium, an endoskeleton and a buncha internal organs. Alright, who remembers when I explained that biology is always changing?”

Several cones raised their hands and AShoka smiled “perfect, so the naming of stuff in biology is a nightmare, especially when we compare planets to the galaxy at large, in general Naboo uses the galactic standard to name stuff, but even then there are some holdovers, so we’ll see names that should be descriptors be an older part of a linarge, so the bony fishes are the fishes with bones and also the lineages that branched off them. Anyways we’re not starting with them, first are the cyclostomes, the jawless fishes, Echo wanna translate?”

“Circle mouth!” he chimed

“Yea, so there’s the agfish, and the lamprey, circle mouth, they don’t have jaws so they don’t have teeth but they do sometimes have spiky bits that can look like teeth. Jaws are important and they came from gill arches because remember most life started in the water. Chondrichthyes are shakes and such, they have jaws but teeth aren't super set in, and they’re denser than water so they’ve gotta move a lot and fill their liver with oil to stay alive. Sharks you may have heard, have to keep moving so they don’t die, this is true because they need to swim forward to push water through this gills, and because that’s how they breath it’s a little important.”

Fives chuckled and muttered something to Echo, who cuffed him on the back of his head.

“Osteichthyes fishes with bony skeletons, oste like osteo which I think are bones, anyways they’ve got a bony skeleton, a flap called the operculum that covers the gills and a swim bladder, so unlike sharks they’re buoyant! The ray-finned fishes are easy to remember because Actinopterygill literally translates to ray-finned, just like sarcopterygii is lobe-finned, unlike ray-finned fishes they’re finns are supported by skeletal extensions that supports muscles and they’re the ones who will eventually branch off into coelacanths lungfishes and tetrapods, so because they’ve got the pressessor to limbs we will eventually escape water. Over time the front fins will develop into front limbs that can maybe escape water. Although first you need fish that can gulp air, lungfish, being able to breath air means they can, overtime, develop to fully breath air, rather than being in and out of the water. Going in and out of the water makes them amphibious. They have two life stages, and start in water then move out, they reproduce sexually and are frogs and are divided into anura frogs and toads, apoda caecilians and urodela which are salamanders.

“The amniotic egg sheltered embryos when moving onto land, keeping them safe and preventing them from dying out, because most development needs to be done wet! Reptiles are now here, if you remember the messy mesozoic from earlier then you’ll remember Naboo’s dinosaurs ended up including birds, this is because the common ancestor of reptiles and birds is the same creature. Of the reptiles there are testudines or titles, squamata lizards and snakes, crocodilia and aves. Mammals show up next, they’re milk producing amniotes, they have mammary and sweat glands, hair cephalized teeth, and an enlarged skull. They also have their own subgroups, prototheria which are older and lay eggs, meatheria, marsupials, which are mostly in one region in naboo, and there Eutheria which are placental mammals”

Ashoka’s grin was manic “that’s all of my notes, so we’ve caught up to the material I need to know for my exam tomorrow. Thank you all so much, I’m going to go pass out and review everything one more time in the morning.” and with that the padawan swept herself out of the room, looking truly exhausted.

“Good luck commander!” every trooper called after her, but she was already half asleep and barely processed the words more than a warm feeling in her soul.

#college #writing #study fic

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