When you look in your syllabus and it says what reading corresponds with this lecture, then your jaw kind of drops because it's like chapters 14 through 17. We're not going to cover every tiny... little detail in those four chapters. But the species, which there are over 10 million species known on this planet and many others that we probably still have no idea that exist in some of the deepest parts of our oceans or the deepest parts of the tropical rainforests.
There are so many unclassified species today that we just can't cover them all. So my main objective in this is to give you a sampling of what species you have in each of the kingdoms and the domains. And more often than not, I like to choose the ones that will relate to ecology later on when we start talking about ecosystems and making ecosystems stable.
So that's why I've chosen many of the species that I'm going to talk about because they relate to the final chapters that we're discussing on. on ecology. Now, the first and most important aspect of this lecture is what is a species? When we say, oh, this species is here, this species is there, when we say this is a different species, what do we mean by species? Well, it comes down to two main concepts that must hold true if we were to say that this species is different than this species.
And it comes down ultimately to reproductive success. If individuals belong to the same species, then they must first be able to breed with one another. They have to have the capacity to have sex, or if it's not sexual reproduction, at least combine their genetics into that zygote or whatnot.
Now, this is mainly in sexually reproducing species because when... you have asexual reproduction, then they pretty much just clone themselves. So when we talk about species, yes, we can define two organisms as different species if they don't mate with one another, but for things like bacteria and whatnot, that's not too big of a problem or an issue because they pretty much clone themselves. Now, so the species, individuals that belong to the same species first must be able to mate, and second, must be able to produce fertile offspring, which means that their offspring can also continue to mate.
We'll show that in a lot of cases you have animals that are closely related enough that they can produce offspring, but the offspring is sterile, like a mule. You know, a horse and a donkey, which are separate species, but they produce a mule. Well, horses and donkeys are still separate species because mules are not fertile and cannot propagate their species from one generation to the next. So, these are what we call repotting. reproductive isolation barriers.
That's what defines a species. So we're gonna talk about eight different reproductive barriers. Five which are called prezygotic. Now remember, the zygote, is when the sperm fertilizes the egg. That is mating, essentially.
The fusion of the sperm and the egg. So, prezygotic means that they don't have the ability to create. the zygote.
This is where mating comes into play. So prezygotic barriers are where they can't mate. Postzygotic is they mate but there's problems with the offspring that the offspring cannot control.
continue to mate and that also creates that barrier, that reproductive barrier that separates two species from one another. So here is the list of all eight that I'm gonna want you to know. Now, before you get too worried about this, this is, you only have like one or even two questions on this out of your 10. So there's a lot to cover.
I'm going to talk about each one of these isolation mechanisms. but you're only gonna have really two questions of these eight. So don't think that this is the majority of this.
But like I said, it's randomized as far as which ones you get. So you do have to study all eight, but they're not that difficult to understand. All right, let's start with the prezygotic, or before their inability to mate with one another. Notice there's a lot more in the pre than there is in the post. Now the first one's very simple.
It's called ecological isolation. Sometimes also called habitat isolation. The reason for that is because Oregon Organisms mate with other organisms that are in the same geographical area. You have to come in physical contact with another of your species to be able to mate.
So if there is a barrier physically, where they cannot mate with one another. That's one example of an ecological isolation. Sometimes, however, you do have scenarios where you have species that live in the same area, but because their eating habits are different.
Their sleeping habits are different. They don't mate with one another, even though they possibly could. It's because they never interact with one another. An example I like to use with this is if my wife was dedicated to eating at McDonald's, I would never have met her because I don't go to McDonald's.
I go to Arby's. Now, thankfully, she's an Arby's woman. So that's not where I met her, by the way.
But ultimately, ultimately, ecological isolation there must be some type of interaction for the organisms to be able to mate with one another. So if there's some type of isolation in their habitat where they never meet, then they never have sex and they never have offspring. That's one of the reproductive barriers.
The second one is called temporal isolation. The timing of their reproductive cycles is off. Now, ultimately, there's a number of examples with this. For example, field crickets.
There are two different species. One which mature and are reproductively active at one time in the year and the others at a different time in the year. So even though they're in the same habitat, they don't reproduce with one another because the timing of their reproductive cycles is off.
Now this rarely happens with mice because mice ovulate every three freaking days. So they could get pregnant every time they have sex. Another example of this is trees. A lot of trees are blossoming. already and ready for fertilization.
But notice there's other trees that are right next to them that still haven't produced their flowers yet and therefore there's going to be no cross pollination because they're going to be reproductively active at a different time in the year. And so that's really what temporal isolation is. You can have two species of trees that are right next to one another but one's ready in the spring and the other's ready in the summer and never the two shall mate essentially. Behavioral isolation.
This comes down to, you know, essentially what we looked at with the some of the birds and whatnot. The different activities that attract the mates to one another. Now this can be pheromones, this could be mating calls, one again, example here is that you have two species of frogs and because of some slight genetic differences one frog has one mating call another frog has a different mating call and therefore they don't attract others of this of a closely related species.
And so they remain separately as different species because they don't attract others of the other species. So behavioral isolation, the pheromones, the activities, the coloration, whatever the case may be, and this is part of sexual selection as well, ultimately does not attract other organisms that belong to different species. Which is why we consider them separate species because they don't mate due to that isolation.
Now mechanical isolation, you look at the mating organs are incompatible with one another. And we're not talking about just like the penis and everything like that. We're talking about things like, for example, pollinators.
Some insects can't pollinate some flowers. are too small for them. So these insects can only pollinate flowers of a different size. And this is, again, another type of sexual selection that I've talked about.
The different size or shape of the flowers ultimately only attract certain pollinators, which is why when those pollinators go from tree to tree of the same species, that's why they cross-pollinate, they can't get to the other flowers of other species. Now, for most cases, it's very easy to understand, you know, very distantly related species. But this is when we start splitting hairs.
Why is it that these two, which look identical to one another, aren't the same species? And it's because they attract different pollinators. They will not... cross-pollinate between the two because of the different size of their flowers and whatnot. And then the last but not least, let's say that you live in the same place, that your reproductive cycles are on, the mood is right, and you're getting the dance right, and you got the right mechanics, if you know what I mean.
Ultimately, you get to this last barrier where you could possibly have the species mating or attempting to mate, but there's what we call gametic isolation. This comes down to actually things on a On a molecular level, we have this sperm-egg recognition, where ultimately the sperm will only fertilize the egg of the same species. Now this is especially important, especially in the oceans, where you have fish and sea urchins that they don't mate with each other like you and I mate, as far as the human species. They especially just send their sperm into the ether, and the others send their eggs into the ether. And so you have this huge, massive mixture of sperm and eggs in these ocean environments that if you didn't have this sperm egg recognition, you might get some problems occurring between the fertilization of the wrong species.
And so there are these protein receptors that are on the surface of the sperm, as well as on the surface of the egg, that ensure that only members of the same species end up having that fertilization. And again, this comes down to genetics. This comes down to individuals that have the same hereditary genetics that have been passed on.
And this is ultimately where you start getting divergence of species, where you have two different sea urchins that may live in the same area, but they never mate with one another because the sperm and the egg are incompatible. Hybrid viability. This ultimately occurs when the hybrid, the zygote will not fully mature.
Sometimes you get the seeds forming, but they will not. germinate and whatnot. In fact, that's what most of the seeds that you buy in the store today is they're hybrids. They've been genetically modified so that they will not produce seeds, which is ridiculous in and of itself.
But hybrid inviability, you create the zygote, it starts developing but it doesn't come to full sexual maturity it's either not born or doesn't come to a sexual maturity you're welcome to close the door if it really bothers you okay hybrid infertility this is the music mule. This is the example of the mule. Horses can mate with horses and have more horses.
Donkeys can mate with donkeys and have more donkeys. They are separate species. Even though they're so genetically similar that when a horse and a donkey mate, they can produce an offspring that is viable. So this is what we call hybrid infertility, sometimes also called hybrid sterility.
Now, another example. We've got a lot of these. Some of them Pretty crazy. Lions and tigers can create a liger.
Yes, they are real. Even if you're watching Napoleon Dynamite, they are real. In fact, scientists study them because what's fascinating is they grow huge.
If you look up a liger on YouTube, you'll see that. They're enormous. So a lion and a tiger is a liger.
In fact, if they reverse it as far as male, they do a female lion or a lioness or whatnot. And male. tiger you get what's called a tigon and there are some differences between them or whatnot.
Now scientists have done some crazy stuff where they've taken the sperm from a whale and mated it with the egg from a dolphin and they've created a wolfen. I'm not joking. So this is another example of hybrid sterility.
Now this is when we start you know you never get that happening in the wild really and in these cases too this usually happens in cats. activity, not in the wild. But horses and donkeys, yes, that absolutely happens in the wild. But some other cases are ones where we've kind of, you know, you know, created the mood for them and all kind of stuff, or just taken the sperm from the whale and put it into the, why? I don't know.
Now, the last one, and the last minute here is called hybrid breakdown. Let's say that the hybrids are viable and they reach sexual maturity. And let's say that the hybrids are viable and they Let's say that they're not sterile. And in fact, this is the case for some mules.
I say that most mules are sterile, but we have seen some situations where the mules are fertile. Well, here's where we get to the final and last barrier, and that's called hybrid breakdown. This is when the hybrids themselves can have offspring, but that offspring can't mate.
And so you're still stuck at the hybrid stage. You don't. get propagation of the species. Now, if all of a sudden mules produce fertile offspring, boom, we have a new species.
In fact, this is what happens especially with trees is that you get these hybrids that the trees have actually been able to overcome some of the problems. It's animals that really have a big problem with the hybrid sterility and whatnot. Plants have less of a problem with that.
But those are what we call the post-zygotic barrier. Now, in the past, we used to classify organisms based ...only upon their phenotypes because that's what we could analyze. We didn't have a lot of the genetic analysis that we have today, but we look at the proteins and we look at the nucleic acid sequences. Now that foreign the basis for our classification system, but since then we've had to readjust certain things because ultimately with our knowledge of DNA and amino acids we've been able to look at the genetic and molecular relationship of organisms based upon the commonality of the sequences that they have in their DNA as well as in their amino acids.
And this is what's called taxonomy. Now this is not the same as taxidermy. Taxidermy is essentially taking the skin of animals and putting it over and stuffing them, so to speak.
But taxonomy is organism classification. This is where you get into things like bioinformatics, where we take samples of these species, We run their DNA through sequencing. We look at the...
a sequence of their nucleotides and their subsequent amino acid sequences, and ultimately put them in a category where they are most closely related to. And this has allowed us to ultimately create a branching, essentially, tree of life based upon the biochemistry, which is the amino acid sequences, and the genetics, which is the nucleic acid sequences, based upon those similarities. So when we see... when we look at various genes such as in this case this is the gene cytokine c that's found in all these organisms the more differences that they have as far as their sequences the more distantly related they are and therefore in different taxonomies or different classifications or groups so this is what we call phylogenetics phylogenetics is essentially looking at the organism's evolutionary relatedness based upon their DNA and their proteins.
Because we have to look at both. It's not just the DNA, because if you remember back from lecture 10, we talked about how you can have synonymous codons, where you can have AAU and AAC, and they can mean the same protein. So in those cases, you could have slightly different changes in the nucleic acid sequence, but the same amino acid sequence. And so we look at both.
We look at both the changes in the genetics, that there's some flexibility within, even within the same species. And then there are modifications that occur that... are differences in the amino acid composition and therefore makes the protein have a different function. And we'll look at some of the dynamics of what that does when you have these mutations in the amino acid sequence and ultimately how that creates, in some cases, huge divergence amongst species that belong to the same maybe phylum. but ultimately have some major differences and therefore are part of different taxonomy groups.
One example of this is a patterning gene called ultrabythorax. This is a gene that's necessary for the patterning of body polarity and segments. One in particular part during development of these organisms is whether or not they develop legs or wings. And they found that in Species that ultimately develop wings, they have this additional sequence of alanines, which we call polyalanines, that in their gene makes it so that the wings develop, whereas in these other organisms these don't have that sequence and therefore develop legs instead of wings in those areas.
So this is just what phylogenetics shows. These letters represent amino acids. And we haven't gone over these, and don't worry about knowing what W stands for, R, or anything like that. But here, this is just to show you the side-by-side comparison that, for most of it, it's conserved. They're all pretty much the same amino acid sequence in these alleles, but here we have that all of these have some arrangement of polyalanine, and that's ultimately what makes the difference between whether this gene causes wings to form or whether legs form in these segments of these insects.
Now, how we classify organisms comes down to a two-fold naming process. In fact, the hierarchy of classification we're going to go over here in just a second is similar to what we went over in the beginning of the semester where we look at kind of this greatest to least or least to greatest, just kind of how we looked at the organization of life from the smallest to the most complex. Well, as far as classification goes, you have domains or...
areas where they include pretty much all life. And then as you get more and more specific, they become more and more restricted to their particular classification. Now, we've all heard of humans being homo sapiens.
In fact, the two-name classification comes down to what we call the genus and the species. Now, we've already talked about what the species is. Two organisms, if they belong to the same species, must what?
They must be able to do what? Produce offspring. How do you produce offspring? I know you guys know this. How do you produce offspring?
Yeah, mating. Okay, so they must be able to mate with one another and the offspring must continue to be able to mate with each other. So that's what ultimately causes two individuals to be part of the same species. Now, in some cases, they may be so closely related that they're part of the same genus, but due to some reproductive barrier, they are different species.
And you've heard a lot of these names before. For example, E. coli, the E we just abbreviate because the actual name is called Escherichia. E is much easier to say.
So E. coli, that strain of bacteria. We've got Canis lupus, those are wolves, and so on and so forth. So, Let's look at this hierarchy.
Let's look at this classification. And this is what I'm going to test you on. This actually one's fairly easy. It's not too hard of a question on your exam.
But this is how we organize or classify all the classes. all life based upon their evolutionary relatedness. Now, there are three domains in which we include all life. The bacteria, the archaea, and the eukarya domain.
We belong to the eukarya domain. Back in the day when I was learning this, we didn't have domains. We had five kingdoms. They were the plant, animal, fungi, protist kingdom, and then we had a kingdom called the Moneric Kingdom. Well, the Moneric Kingdom used to include both bacteria and archaea, because they're prokaryotic cells.
Well, due to modern phylogenetics, where we look at the evolutionary relatedness, what we once thought were very closely related are actually very distantly related, based upon their genetic and amino acid composition. And so we've had to reclassify the Moneric Kingdom and actually make it into two separate domains, which are the bacteria and the archaea domain. And we're going to talk about bacteria and archaea today. At first glance, they look pretty much the same because they're both prokaryotic cells, and there's not much differences when you look under a microscope. However, when you really delve down into the genetics, you realize that they are not related or as closely related as we once thought.
All right, now, king... Kingdoms. In the Eukarya domain, we have four kingdoms, and that's where we're going to spend the rest of our time in this lecture on. So the first part, we're going to look at the bacteria and archaea domain and some examples from those species, from those domains, specifically species that are going to come up again and again when we study ecology over the next few weeks. And in the Eukarya domain, we've got four kingdoms, plant, animal, fungi, protists.
So those kingdoms still remain. Those are fairly well classified. Now as you delve into each kingdom, you have various phylum.
For example, in the animal kingdom alone you have nine phylum. We belong to what's called the Chordata phylum, but there's other phylum. There's Anthropoda, which is where the insects and other crustaceans are belonging. In fact, that's the one of the largest phylums in the animal kingdom.
When you break up each phylum, then you have several classes and so on and so forth until you finally get to to that last and final division, which is through reproduction, mating and offspring, like we talked about last time, where you only have one of every species. So this is why we have 10,000, I mean not 10,000, 10 million species that we know of on this planet, and possibly many, many more that we don't, haven't even investigated yet because of where they live. This is why species is what we call the least inclusive because there's only one type of any species.
I'm not saying one animal or one organism but one type of every species. Let's look at the aloe vera plant. Again that's why it's called aloe vera.
It belongs to the aloe genus but the species is the vera. So it's aloe vera. That's the one most commonly used when we get the extract and other types of things.
Well let's look at its hierarchy. It belongs to eukaryotic domain just like you and I, but it belongs to a different kingdom, the plant kingdom ultimately. Then as you start looking at the phylum, you get the atrophytas and then so on and so forth.
biologists, so I'm not even going to try to name those. But at the end, you notice that there are over 500 different species within the allogenes. And ultimately, this comes down to where they grow in the world.
It's not that if we were to take them and put them in the same nursery that they wouldn't be able to reproduce with one another, it's just in nature, they have that ecological isolation, and therefore they will not reproduce with one another because they're separated by physical means and therefore can't reproduce, so they're separate species. But they might all be very, very, very genetically similar to one another because they have the same pretty much genetics and whatnot. Now, because there are so many species, we cannot even cover even a large portion of that. I'm going to pick and choose certain species out in each one of these domains to continue to talk about when we talk about ecology. Your book's going to have quite a bit of information.
quite a few different examples. And you're gonna see several here, but just pay close attention to the ones that I make mention of and point out because those are the ones that I'll not only test you on, but we'll carry on to subsequent lectures. So one of the things about bacteria and archaea that first confused us is they're both prokaryotic cells. So we once thought, hey, they're both prokaryotic cells, they're very closely related because they pretty much are the same type of cell, their genetics are the same, are the same, they pretty much behave mostly the same.
Well, the more we investigate it, the more we realize that's not always the case. They have some substantial differences in their genetics as well as in their proteins in which they do. As well as when we look at ecosystems, they play very distinct roles. Sometimes those roles overlap, but in other times they have very unique roles. And so when we look at those, we have these two separate domains because they're not as closely related as we once thought they were.
Another issue that we sometimes deal with is you get what we call lateral gene transfer between many of these species. Remember I told you how Bacteria can ultimately share antibiotic resistance. That's what this lateral gene transfer ultimately is.
So unlike sexually reproducing species where we pretty much only inherit the genetics that get passed on to us, this would be the equivalent of being next to some other human and them giving you Huntington's disease just by transferring their genes over to you. I mean, that's not going to happen to you. But in...
simple cells like prokaryotic cells, this happens quite a bit. In fact, they have these little regions called sex pili in which they can connect with one another and ultimately copy genetics and give each other genetics. So that makes it a little more difficult to look at some of the classifications because we get this crossing of genetics laterally or horizontally instead of through descent with modification. Now, let's look at some of the similarities and then look at some of the substantial differences. Since they're all prokaryotic cells, then they pretty much have some of the same features, meaning they're lacking most of the organelles that prokaryotic cells lack.
They don't have a nucleus, so they don't have a nuclear envelope like you and I do, or that any eukaryote has, which is one of the main things that classifies them. They're particularly small, about a tenth the size of eukaryotic cells. They pretty much are unicellular for the most part.
And then there's a lot of... similarities as far as their where they're able to grow their chromosome composition and whatnot they don't really have chromosomes but it's a circular plasmid that's their DNA now let's look at some substantial differences one of the things that we notice right off the bat is though bacteria and archaea have a cell wall they're not made of the same thing bacteria they make their cell wall out of a protein carbohydrate composition you called peptidoglycan. And that's really where it gets its name. Peptido has to do with the peptide bonds that hold amino acids together.
Glycan, like if you think of glycogen and things of that sort, that's the carbohydrate. So unlike plants, which make their cell well, purely out of sight. And unlike fungi, which make their cell wall out of things like chitin, bacteria, they'll make their cell walls out of both carbohydrate and protein.
And there's many different configurations. You've got different types of levels of their cell wall, and when we stain them, this is where we usually come to. the gram-positive or gram-negative stains, depending upon the composition of their cell wall. But the main composition of this molecular basis is peptidoglycan. Now, we once thought that archaea also had the same cell wall.
wall but they found on closer inspection that it's not configured the same and that on a molecular level is huge it makes a big difference so instead of calling it peptidoglycan we call it pseudo peptidoglycan because pseudo Pseudo is kind of like fake or not the same, it's like a different version of it. So pseudopeptidoglycan is what Archaea make theirs out of. Now I'm gonna focus more on bacteria. The peptidoglycan, you're gonna see that word pop up a couple times over the next week or so in terms of looking at some of the similarities and differences between species.
If I were to ask what plants and fungi and bacteria are doing in the world, their cell wall out of. That's one of the distinguishing characteristics is the composition of their cell wall. Now, here's another big difference. In the bacteria domain, we have found some species that, though they don't use the organelle chloroplasts, because remember, chloroplasts are the organelle that plants use as well as other organisms used to undergo photosynthesis. They, however, do have chlorophyll, and this pigment is able to capture sunlight.
And so, in this manner, these bacteria are photosynthetic. To date... we have not found any archaea, or what we classify as archaea, having the ability to undergo photosynthesis.
They don't have chlorophyll. Now this is huge, because this illustrates a big division in a lot of these species. So, I might ask you regarding some of the main differences between bacteria and archaea, and it might come down to this right here.
Bacteria have some organisms, or some species in this. in this domain that have the ability to undergo photosynthesis. Whereas today, we do not have any archaea that have the ability to capture sunlight and turn them into sugars. All right, now let's look at some of the diversity within the bacteria domain as well as the archaea domain.
Within the bacteria domain, we have at least 23 phyla. They're very diverse. There's some that are photosynthetic. Nitrogen cycling, this is another aspect that's key for ecosystems.
These bacteria are able to undergo anaerobic respiration. Remember that anaerobic respiration, as we learned, is the exact same process as aerobic respiration. The difference is they use nitrogen instead of oxygen. Well, how does this play a key role ecologically?
Ultimately, the decomposition in the soil and the putting of nitrogen, such as nitrates like ammonia and... and nitrate or whatnot, these are necessary chemicals for plants to be able to synthesize their nucleic acids and their amino acids and such. Without bacteria being able to take nitrogen gas from the air and fixing it to these ammonia nitrates, ultimately we wouldn't have stable ecosystems like we have today. Okay, so decomposition does one aspect of recycling nitrogen, but without these bacteria, we wouldn't have the ecosystems that we have today.
They're very important for maintaining nitrates within the soil for plants. Now, we've already talked about some of the medical importance of bacteria, especially when you get into transgenic organisms. You know how we synthesize insulin by ultimately putting the human insulin gene into bacteria. We're able to synthesize pretty much anything if we know the genetics behind it in bacteria.
bacteria so they play a key role medicinally in fact we also can use them to synthesize antibiotics believe it or not so the bacteria as you notice doesn't have a nuclear envelope it has this large nucleoid or chromosomal DNA which is if you were to unravel it it should be one large circle their cell wall is made of peptidoglycan as we talked about and they can actually take up DNA from the environment which is one of the things that makes them very difficult to deal with especially when they are able to crosstalk with other bacteria and share that with them. They are also important for our food. We use them in the production of many of the things that we enjoy today. Vinegars, pickles, olives, yogurt, cheese.
We use them to make industrial chemicals like ethanol and acetone and even vitamins. Transgenic bacteria, we talked about that with insulin and other types of human growth hormones. We use them for bio waste treatment.
This is huge to be able to basically break down the sewage that you and I excrete as well as many others and ultimately A lot of these sewage plants pretty much run on their own energy produced by the breakdown products of the waste treatment. And so it's a wonderful way of recycling that makes our way of life manageable. So, many, many, many benefits of bacteria.
Most of the time, when we think of bacteria, we think of certain things like cholera. You know, that's the bacteria we hate. We think of salmonella.
We think of chlamydia. We think of strep. We think of tetanus. We think of anthrax.
These are a lot of the bacteria that we think of because they cause the diseases that plague us so much. But in reality, without bacteria, we wouldn't have stable ecosystems, we wouldn't have the medicines that we have today. Bacteria play a key role.
and whatnot. So bacteria kind of get a bad rap. Every time we think of bacteria, we always think of infection and diseases and things of that sort. But I want to make you aware again that without them, we wouldn't have what we have today. Here's an example showing you how in the nodules of these plants'roots, the bacteria live and they're able to convert nitrogen gas into ammonia and nitrates that are necessary for the plant to be able to have the necessary building blocks for its cells.
Now let's talk a little bit about some of the problems with bacteria because this is where food poisoning, this is where weaponized anthrax, this is where a lot of these things come into play. Bacteria are very resilient. They have the ability to, in very harsh environments, kind of package up all the essentials of life and put them into this spore that is able to withstand. at extreme temperatures, radiation, any types of things that we try to get rid of them, they'll pretty much just sit there and be protected and be like, oh, I don't care what you throw at me.
This is where a lot of food poisoning comes into play. Because when we can our food, we're usually canning a lot of this bacteria in with it as well. But when you open up the can, and if you let it, once it gets into a favorable environment, it can actually start spreading and releasing its toxic metabolites, and this is where botulism comes from. In fact, Botox is botulism toxin.
So, next time you think about Botox, This is a toxin that causes an inflammatory response in your body. Now if it gets into your bloodstream, it can kill you. Now anthrax is another one that we are a little scared of because that's really what weaponized anthrax is, is scientists or individuals, terrorists, will take this bacteria, force it to go into this spore state and then you can put it into an envelope or some other thing as we've seen in the past. Because what we're seeing is that once they get introduced back into a biological organism, they're able to literally revert back to their normal form, grow very rapidly, release their toxin, and can very quickly kill somebody. All right, and this was just the example that I showed you that bacteria have the ability to share genetic information.
Sometimes it is transmitted virally, sometimes it's between the actual bacteria themselves, between these sex pili. Don't worry about these words, transduction, conjugation, transformation, don't worry about that. But ultimately, bacteria have the ability to pick up DNA from a multiple host of sources, and this is where they are able to increase their ability to survive.
because they're picking up antibiotic resistance from other bacteria. In fact, this is a problem today when we deal with studying bacteria. Some bacteria we can't study in the same lab because if they were to ever talk with one another, they would share all of their resistance and you'd have something even worse than MRSA in terms of its resistance to most of our antibiotics.
All right. Now, archaea are much simpler in terms of understanding the main types of organisms that belong to this domain. There are archaea that do live in normal environments, and there are bacteria that do live in... in extreme environments, but on the whole, generally speaking, we say that bacteria are the ones that we typically come in contact with in the regular environment, and archaea are the prokaryotic cells that typically live in extreme environments, hence we call them extremophiles.
So, extremophiles are the ones that Extremophiles live in areas that not many organisms can. And there are three main types of extremophiles that I'm going to test you on or that I want you to know. And these play various ecological roles in various parts of the world. and generally you'll get other organisms playing these same roles in the more temperate areas. So methanogens, these are methane-producing archaea that convert carbon dioxide into methane gas through anaerobic respiration.
You'll find these in areas where you have high concentrations of carbon dioxide and therefore high concentrations of methane, such as in swampy areas and the like. Halophiles, these live in extremely salty areas, like the Great Salt Lake and the Dead Sea and some other areas where the salt concentrations are so high, you're not gonna find fish, you're not gonna find many organisms, but you do have these microorganisms living in these areas because they're able to withstand the extreme salt. concentrations that are found in those particular areas. And then thermoacidophiles, the name tells you where they live.
Thermo has to do with heat or temperature. Acid has to do with pH. So these live in very hot acidic environments such as these hot springs and thermal vents in Yosemite and whatnot. They live in these areas and have various roles in decomposition and whatnot.
But notice, not many things are going to be able to live in those hydrothermal vents that come up and create a very acidic environment and very hot. Now again like I said it's not to say that all extremophiles are archaea, there are some bacteria that live in thermal, you know, hydrothermal vents and things of that sort. And there are archaea that live in just the plain old soil.
However, for our purposes, we'll just kind of keep them nice and separate for testing. So it's all about the Eukarya domain, which is one of the the most diverse group of organisms and though pretty much the the thing that classifies the eukaryotic domain is every organism that belongs to the eukaryotic domain is made of eukaryotic cells. Now there's a great amount of diversity within each of the kingdoms. In fact we still don't have our full classification together.
What do I mean? Well let's look at the first kingdom, the kingdom protista, sometimes just called protus. Look at this. We don't know what the hell we're doing. Okay, what I really mean by this is there are so, there's so much diversity in the protist kingdom.
There might be as many as 20 different kingdoms here. You can see that we're already discovering some of these groupings or branches through phylogenetics. But here's the most interesting thing.
If it's not a fungi, animal, or plant, we throw it into the protist kingdom. I'm not kidding. So this is where we put things that are not very important.
very well defined as a fungi, as an animal, or as a plant. So look at this branching, I mean it's just enormous because you've got some protists that are very, very similar to plants. In fact, we once thought of them as plants and we now realize they're not.
There are other protists that we once thought were fungi, but then we're like, oh no, the genetics are too different and whatnot, and they're not fungi. So let's start with the protist kingdom, extremely diverse. Now. Now, even with all of this diversity, there are a couple of organisms that are key for any ecosystem, which is why I'm gonna cover them, and those are specifically the photosynthetic protists.
Now, here's the fascinating thing. Most photosynthetic activity on our planet is not done by plants, it's done by protists. Think about it, our planet's mostly covered in water, two-thirds covered in water. These are accrued.
aquatic photosynthesizers. The main group of photosynthetic protists are algae. Algae play a key role in any aquatic ecosystem to undergo photosynthesis to bring energy into those aquatic environments.
Another thing that's key for the survival of any ecosystem is typically the symbiotic relationship that algae play with other organisms like fungi, where they form what's called a lichen. And these lichens are usually used to determine the quality of the air and the stability of the ecosystem because they're the colonizers. They're the ones that actually start ecosystems and are there throughout it.
So algae is an aquatic protist that is able to photosynthesize. Now, even with that, there are so many different types of algae. And they're usually named for the assortment of pigments. Now. that are found in their cells, like green algae.
Red algae, gold algae, brown algae. The one I'm most familiar with is brown algae. This is what we refer to as seaweed.
It's kind of plant-like but these aren't leaves. We call them blades. They are able to undergo photosynthesis.
And the buoyancy of the air filled pockets ultimately allows the plant to stretch up and be able to receive that sunlight. I mean sunlight can penetrate over 100 feet into the water, so you have a lot of photosynthetic activities still going on. even some of the deeper parts of the ocean. However, it's not a plant, it's a protist.
You've got green algae, okay, which sometimes gets confused with moss. It's not the same as moss. Moss is a plant, but green algae is a photosynthetic algae or protist. Now, So this is definitely one of those that I'm going to test you on. In general, algae.
I'm not going to make the distinction between gold, green, and these different types of algae. Now if you look back on this right here, again that's where you can see this group of golden algae. and you've got red algae over here, and so on and so forth. I mean, there's all sorts all over the place. Now, let's look at another one.
If you've ever heard of red tides, these are caused by a protist called dinoflagellates. These protists are the major component of what we call plankton. And they're the ones that will use up much of the resources and they excrete a toxin and this is where you get the red tides.
Now, when you have filter feeders like mussels, and if you were to eat that, this is where you're gonna get that shellfish poisoning. Is if you eat them after they've filtered out a lot of these toxins that aren't toxic to them but are toxic to you and I. So these are also protists that ultimately excrete this, and this is where we get the red types. Diatomes are another type.
These are interesting. If you've ever heard of diatomaceous earth, they're essentially diatomes. These ultimately have these very beautiful colorations and configurations made of silicon.
And so a lot of this forms a lot of the seabed. These protists live in the seabed and form a lot of the composition. of that.
So if you were to take some diatomaceous earth from like Good Earth or some of these other places and look under a microscope, this is what you'll see. It's pretty cool. There's other applications such as cleansing your body.
You're literally putting glass through your body or putting it around your garden to prevent snails or other things. Works really well for that because they don't like the going over this area of kind of glassy remnants of the of these cells. classified as fungi but due to phylogenetics we realize hey they're not for a number of reasons not only are their genetics very uh different from fungi but they don't even make a cell wall like fungi do they don't make a cell wall out of chitin um unlike fungi and that's one of the major things that fungi do is that in order to reside within the ground and be in the environments that they do they have to have a very tough rigid cell wall made of chitin that surrounds them. And these are what we call slime molds.
Now these, unlike fungi, actually live on the surface. Fungi actually live in the ground, even though you do see the results of sex, which we'll show, which are the fruiting bodies or the mushrooms. Slime molds actually go along the surface and they eat bacteria and recycle nutrients or whatnot.
All right, so I'm gonna skip ahead to fungi here since we're already on that. Usually. talk about fungi before plants anyway.
But fungi are vital for the stability of any ecosystem. Why? Because their main job is decomposition. In any ecosystem, they are the major recyclers. They live in the dirt, in the roots of trees.
They live in these areas and they're going to recycle essential nutrients back into the soil. Now that's really where we initially discovered antibiotics. is because fungi eat bacteria.
Well, ultimately they secrete these chemicals outside of their cells, which break down the bacteria. And that's where penicillin was first discovered, was one of these types of secretions that ultimately block the bacteria from making their cell wall. And from there, we've been able to derive other types of chemicals that are used as an antibiotic, but that's how we first discovered antibiotics.
Now, don't go taking a fungi and boiling it down down and making your own antibiotics, you're going to kill yourself. But we've been able to synthesize many antibiotics from these excretions. Now, What's interesting about fungi is in terms of their genetics, they're more closely related to you and I than to plants. In fact, we use fungi many times to study our own genetics because some of their molecular mechanisms are very similar to you and I.
Now, let's look at the fungus. Most people have never actually seen the fungal filaments. What you've seen is the mushroom. But in reality, the mushroom is essentially like looking at the fungi. sexual anatomy because that's the result of sex.
So the fruiting body, ultimately the mushroom is where the spores get produced, which are the result of meiosis. So when two fungi get together and the mood is right and they fuse their nuclei, they essentially create the fruity body which becomes the mushroom. And this is its reproductive process.
From the mushroom it will create these haploid spores. Now that's another thing about fungi that's interesting. These filaments, because this is what the fungi actually is, these filaments are all haploid. You remember what haploid means?
It means they only have one of every chromosome. Now this is the opposite of you and I. Our cells...
are diploid. We have two of every type of chromosome. Well, each fungi is haploid, and when you get two of the mating types together, we call them plus and minus, there's no male and female in the fungi world. Maybe they consider themselves that, but we don't.
So the plus and minus mating species get together, fuse the haploid cells into a diploid cell. That diploid cell creates the mushroom, and then it undergoes meiosis, creating the haploid spores that will then disperse. and spread the fungus. So the main body of the fungus we call mycelium. The mycelium is what the fungus actually is.
This is what spreads to the ground through mitosis and reaches out and undergoes decomposition. The filaments of the mycelium we call hyphae. These are just the long filaments of cells of fungi that are connected together and form almost like roots, okay? But these are the fungus.
This is the actual... fungus itself. This just illustrates that what I was just talking about. The haploid spores fuse, creating a diploid cell. They germinate.
You get mitosis creating the mushroom. However, the spore sac, that undergoes meiosis and creates haploid spores. And that is what gets dispersed throughout to be able to spread the cells.
So fungi actually reproduce through two mechanisms. Asexual, they clone themselves, and sexual, they fuse their nuclei, just like a sperm and an egg come together, and create a diploid cell that then can undergo meiosis and create these haploid cells. Now another key thing about fungi is they form symbiotic relationships with other organisms.
I mentioned the lichen. This is an example. The lichen is actually two different kingdoms coming together. It's either fungus and algae or fungus and bacteria. bacteria, usually a cyanobacteria because that's where the symbiosis comes into play.
The role of the algae or the bacteria is to undergo photosynthesis, and this is where you're going to get a lot of these colorations because of the pigments in the in the chlorophyll. and other pigments that are necessary for photosynthesis. Well, what do the fungi do?
Well, they protect the algae from its vegetarian predators, essentially. So the lichen is very tough and resilient, and the organisms that would normally eat the algae can't. And so in this symbiotic relationship, the algae or the bacteria give the fungi nutrients, and the fungi in turn protect the algae.
And this is one of many cases of symbiosis that we're going to talk about. Again, like we said, they use lichens to monitor air quality because this is because of the nature of their ecological importance. So let's look at some of the general characteristics of fungi. The main body of the fungi is mycelium.
The cells are haploid. So the adult cells of a fungi are haploid, not diploid. They only become diploid when they fuse together in presence of a cell.
preparation for sexual reproduction. They make their cell wall out of chitin. This is the same material that is used for the exoskeleton of crabs and insects and lobsters and such.
It's very tough. That's why mold is very difficult to get rid of chemically because these can withstand very extreme environments. They can reproduce asexually, which is mitosis, and sexually when they fuse their haploid cells together, create the mushroom, and then those cells can undergo meiosis, create the haploid cells again, and then spread through the air. job is decomposition and colonization.
The colonizers, this is when they form that symbiotic relationship with the algae and the bacteria and that's what starts the the formation of the soil and things of that sort. Now, we know about fungi for food. We have mushrooms a lot in our food. We use medicines like the antibiotics that we've discovered from fungi. Most of the time when we think of fungi, we think of disease.
And a lot of times we don't particularly like that aspect of them. However, even disease plays a key role in the stability of ecosystems. Okay, two more kingdoms to discuss and then this will be finished up and then we'll do a review.
since this is one of the more broad topics it's important you understand how many questions you're gonna have on each kingdom and domain and what how they're gonna be phrased and some of the other things so you can prepare for it because there's just so much to read about in your book well as to go over. So plants. The plant kingdom is very well defined. In fact, all plants are multicellular.
We do not have any plants that are single-celled organisms. Those are all multicellular. cellular, there are no single-celled.
With a few exceptions, all plants are essentially photosynthesizers. So these are what we call autotrophs, or the ability to make their own food through the photosynthesis process. And almost all plants live exclusively on land. So remember we talked about the protists and being aquatic photosynthesizers?
Well, plants are their counterparts on land essentially for their ecosystem. ecosystems. So protists play a major role in a lot of aquatic ecosystems. Plants play a huge role in the terrestrial ecosystems on our planet.
So let's look at some of the ways in which we classify plants and some of the groups. There are actually four major groups of plants. Now these are not, I'm not going to necessarily test you on each individual phylum and things of that sort. Remember we have the kingdom, which is the plant kingdom, and then and below that we have the phylum. Well, there's four main groups of plants that we're gonna go over.
We first have the seedless, nonvascular. So the seedless nonvascular plants, one of the most abundant types of plants that belong to this group are what are called bryophytes, or the true mosses. Now when we say true mosses, the reason why we we say true mosses is because other plants have the name moss in them like club moss and spike moss and whatnot but they're not true mosses that's how we classify a moss so if you look at you know some moss on a tree and say oh yeah that's a moss and then you look at something like a club moss and be like, nope, that's just the name of it.
It's not actually a moss. So more naming problems that scientists have. So the bryophytes are the major group of organisms. Now, they don't grow very tall.
They're non-vascular, and so they don't have a root system like other plants do. They don't have an ability to draw water up into high heights and large areas and whatnot. not so they remain relatively small so when you look at a moss this is a close-up version of them but they don't grow very tall okay so mosses liverworts hornworts these are examples of the seedless non-vascular now seedless doesn't mean that they don't reproduce it just means that in their reproduction process they don't encase their sperm in pollen grains nor do they produce the seeds that we normally associate with plants. So there is still sperm and egg and they still do undergo sexual reproduction, but these will live in very watery environments where reproduction can occur. So that's why you'll find mosses and hornworts and liverworts living in areas with a high amount of water and such.
So those are what we call the seedless non-vascular plants. Now the next group is a little more advanced. They're also seedless so they don't produce seeds like we would think about. They don't encase their sperm and pollen grains and whatnot but they are vascular. This group, the primary plant in this group are the ferns.
So we We all know about house ferns and things of that sort. Ferns and their allies, as they call them. This is where club mosses and other things come into play, which is why I'm not really going to bring in club mosses on any examples because it just... This tends to confuse people.
In fact, I tend to use the word bryophytes more often than not when describing the seedless non-vascular just because it helps to keep it nice and clear. Ferns again is the more abundant. within this group, they have a vascular system made up of two areas called xylem and phloem. And this is ultimately the structure that takes the water up from the roots into the trunk of the or main stem of the plant, distributes it to the leaves. The leaves undergo photosynthesis.
They take the nutrients and through the phloem redistribute it to the rest of the cells where they can then use that nutrients and that energy produced through photosynthesis. So... Ferns and their allies, these are the seedless vascular plants.
Now, gymnosperms. These are the seed vascular. However, they are non-flowering.
So they do encase their sperm in pollen grains. They do produce seeds like pine trees. If you look at the pine cones, you can actually see the seeds in them. But they're non-flowering. They don't produce flowers, and so therefore they don't...
attract pollinators. They're also, if they're non-flowering, they don't have any fruit production in that regard. Now they're vascular just like the other plants where they have the ability to redistribute fluids through their xylem and phloem. However, they're not the most abundant.
You'll find these in the mountain areas. This is pine trees, conifers, ginkgo plants, and the like. Now, When you look at these phylogenics here, and you can see that there's a large distribution of plants.
It's somewhat misleading as far as the amount or number of species in these groups, because in fact, these three groups of plants are the least abundant plants on our planet, or series of plants on our planet. The most abundant plants are the seed vascular... flowering. Why do you think they're the most abundant and why would that make them have the ability to reproduce more effectively?
Good. So pollinators, insects, some flowering plants or fruit producing that also attracts animals for seed distribution and things of that sort. These are what we call angiosperms. Even grass is an angiosperm.
These are the most abundant plants on the planet. If you were to let grass grow long enough and not cut it, it would produce flowers. So angiosperms are flowering plants.
There are over 250,000 species of angiosperms. So if you look at the overall species count, Mosses, only about 24,000. Ferns, about 12,000.
Pines, only 800 and some odd thousand. Angiosperms, 260,000 different species. So these are the more abundant because in terms of evolutionary advantage, they have the greatest advantage for reproductive success. They're able to redistribute their seeds and be able to spread out to a wide variety of areas, have the greater attraction to insects. insects and other pollinators.
Now, these are the four main groups that I'm gonna test you on. And each one, again, just has one slight difference from the other. These are the bryophytes, or the seedless non-vascular.
The ferns are the seedless vascular. The pine trees, or the gymnosperms, are the seed vascular non-flowering. And the angiosperms are the seed vascular flowering plant. All right, let's look at the animal kingdom. Most of the time when people think animals, they think of vertebrates, which is what you and I are.
However, the more abundant species of animals are actually what we classify as invertebrates, which they ultimately do not house their brain nervous system in a vertebral column. So the general guidelines for the animal kingdom are very well defined. All animals...
are chemo-heterotrophic, which means there are no photosynthesis Now there's always exceptions. There's like some sea slug that eats plants and absorbs their chloroplasts and can do some photosynthesis. There's some strange things out there.
But on the whole, all animals are non-photosynthetic. They're chemo-heterotrophs, which means they have to eat other organisms to get energy. We cannot make it for ourselves. With a few exceptions, all animals are sexist.
Sexually reproducing that is our mode of reproduction But that's also what gives us our select advantage in terms of evolution Because of our diversity and our variation that gets maintained from one generation to the next Now another thing that makes animals have such an evolutionary advantage Over other species is their ability to change Places or move in their environment and this comes down to two types of tissues that you don't find in any other Kingdom And that's muscle and nervous tissue tissue. The nervous tissue allows for higher functioning and reactions to conditions in the environment. The muscle tissue gives us mobility.
Now that's not to say that other organisms don't have any mobility. In fact, bacteria have a flagellum that allow them to move within their environment, but that's not muscle tissue or whatnot and they're very primitive. They have no nervous tissue. So animals by far have the greatest advantage for evolutionary survival because of their ability to respond to...
their environment in ways that others just cannot. Now, there are over a million species of animals, the great majority of which belong to this phylum right here called the Arthropoda phylum, which is where we have insects, crustaceans, crabs, spiders, you name it. There's just so much diversity and whatnot in this phylum right here.
Now, I am gonna go through each of the the phylum so you can get a good appreciation as far as what makes up the animal kingdom. Because as I mentioned, most of the time when people think animals, they think vertebrates. What am I talking about?
Well, of the nine phylum that are in the animal kingdom, only one has vertebrates in it. It's called the Chordata phylum. This is where we belong. Fishes, amphibians, reptiles, birds, mammals, these are the minority.
There are fewer of these species than when you look at the other species. combined, especially like we said the arthropoda. Now the chordata phylum has both vertebrates and invertebrates.
Animals with backbones and animals without backbones. Now, as I go through these, there's a couple videos I'm gonna show you to give you some examples. These are the same examples that you'll typically see show up on the quiz questions, which is why I like to have that connection. But we're gonna go through some, not all of them have videos, but some of them do.
There's no way in hell I'm gonna I'm gonna show the SpongeBob SquarePants movie for the periphera for the sponge. But that's the first phylum here, periphera or the sea sponge. These are some of the more primitive animals.
They are classified as animals, but they're very simple in terms of their overall physiology. Cnidarians. Cnidarians are things like jellyfish and the hydra and the coral reefs and things of that sort.
These are There's a wide variety of various cnidarians. Platyhelminthes are flatworms. These can live in aquatic environments essentially.
They're usually not parasitic, although there are some that can be. Flatworms, various tapeworms and things of that sort. these platyhelminthes, there's a wide variety of them as well. Mollusks are very diverse. You've got squid, octopus, slugs.
You've got the filter feeders like the mussels and whatnot. You've even got some interesting ones that look very much like their ancestors like the nautilus. Analids are essentially worms.
Now these are not like the platyhelminthes where the platyhelminthes are flat worms. These are more round worms. This is where you have earthworms and the like.
This is also where you have things like tube worms. In fact, this is what James Cameron stole for the movie Avatar for his fictional world. These tube worms reside in the sea and can actually hide down into the tubes when danger comes about. how that was.
Nematodes are also another type of worm. Arthropods, this is the most diverse group. One of the main things that classifies arthropods, even though they're very diverse, is they all pretty much have some type of So skeleton made of chitin, okay? This isn't to mean that animals have a cell wall made of chitin.
Remember we talked about how animals don't have cell walls, but they do form an exoskeleton made of the same material that fungi use for their cell walls and this is in place of what we would consider where we have our skeletal system, our internal system. So these are invertebrates. This is how they protect their internal organs and such and their nervous system by having this hard shell.
Now there's a wide variety of different arthropods. One of the more fascinating things about some of these, like for example the horseshoe crab, is its blood isn't red, it's actually blue. And the reason why it's blue is because it uses copper in it instead of iron.
And so scientists every year when the... horseshoe crabs come on land to spawn they will bleed out a lot of these horseshoe crabs because the blood has some type of thing we haven't quite identified yet that is used as a coagulant to show whether or not there are there's a bacterial infection in some of these pharmaceuticals and so pharmaceuticals pay top dollar for the horseshoe crab blood to essentially test their batches of drugs to ensure it's one of the quickest ways to see whether there's some contamination in those batches or not. We have not yet been able to synthesize what's in the horseshoe crabs blood.
Now we don't kill them but they do bleed them out as they come on land to spawn and then they let them go and I think about 10% of them died. They're getting better at it all the time but there's just a wide variety of things that we can learn and and know from these arthropods. Echinoderms. These are things like sand dollars.
sea urchins, starfish. Alright and then we reach our phylum, the chordata phylum. This is the phylum that not only has all vertebrates in it but a few invertebrates as well.
Most of the invertebrates are not as well known such as the sea squirrel, and the lancets. These live in various regions that we don't necessarily encounter them unless we go looking for them. However, this is where we have the fish, the amphibians, the reptiles, the birds, and the mammals. Platypus is messed up.
Well, it's the only mammal that lays eggs.