- [Instructor] When you
look into our syllabus and it says, what reading
corresponds with this lecture, then you, your job I kinda drop because it's like chapter 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. Any others that we probably
still have no idea that exists in some of the deepest parts of our oceans or the deepest parts of
the tropical rainforest. 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 below, what species do 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 ecosystem 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 ecology, okay? 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, I 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 do talk about species, yes, we can define two
organisms as different species that 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 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 horse and a donkey, which are separate species
that 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
reproductive isolation barriers. That's what defines a species, okay. 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, make postzygotic is they mate but there's problems with the offspring. That the offspring can
not 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. And the reason for that is because 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
then 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 the
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. 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 gonna
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 ready in the summer and never the two shell mate, essentially. Behavioral Isolation, this comes down to, you know essentially what we looked at with the some of the birds and whatnot, different activities that
attract the mates to one another. Now this can be fair bones,
this could be mating calls. One example here, is that
you have to species of frogs. And because of some slight
genetic differences, one frog, one meeting call, another frog has a different mating call and therefore they don't attract others of the of across the related species. And so they remained separately
as a different species because they don't attract others of the other species, okay. 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, 'cause 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 there're 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,
very easy to understand, you know very distantly related. But this is when we start splitting hairs. Why is it that these two would look identical to one another, aren't the same species. And it's because they
attract different pollinators that they will not cross
pollinate between the two because of the different sides
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 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 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
them sperm into the ether and the other 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 made 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 archings 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, okay? 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 just ridiculous in 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 (Instructor laughing) Hybrid infertility, this is the 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 we also call
it 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've watched
the "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, that they
reverse it as far as male, they do a female lion and
a or a lioness or whatnot, and a 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
wholphin, I'm not joking. (crowd laughing) 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 captivity, 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
created the mood for them and all kind of stuff, or just taking the sperm from the whale and put it into the why, I don't know. Now the last one in 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 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
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. This 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 postzygotic barrier. Now, in the past, we used
to classify organisms based solely upon their phenotypes, because that's what we could analyze. We didn't have a lot
of the genetic analysis that we have today, where we look at the proteins and we look at the nucleic acid sequences. Now that formed the basis
for a classification system. But since then, we've had
to re adjust 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 and 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 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 side of pregnancy, that's found in all of these organisms. So 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. 'Cause 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 codes where you can have AAU and AAC and they can mean the same proteins. So in those cases you could
have slightly different changes in the nucleic acid sequence, but the same amino acids 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 ultrabithorax, 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 when they found that in a species that ultimately develop wings, they have this additional
sequence of alanines, which we call polyalanine, 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 and those areas. So this is just what phylogenetic shows. These letters represent amino acids, and we haven't gone over these and don't worry about
knowing what W stands for 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
the pretty much the same amino acid sequence in these alanines, 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 forming 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 gonna 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 kinda 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? - [Woman] Produce offspring? - [Instructor] 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, okay. 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, is much easier to say. So E. coli that strain of bacteria, we've got a 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 gonna test you on. The sexual ones are fairly easy, this is not too hard of
a question on your exam, but this is how we organize
or classify 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, proteus kingdom. And then we had a kingdom
called the Monera kingdom. Well, the Monera kingdom
used to include both bacteria and archaea because
their 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 Monera kingdom and actually make it into
two separate domains, which are the bacteria
and the archaea domain. And we're gonna talk about
bacteria and archaea today. At first glance, they
look pretty much the same because they're both probiotic cells and there's not much differences when you look under a microscope. However, when you really
delve down into the genetics you realized that they are not related or as close to related as we once thought. All right, now kingdoms, in the eukarya domain,
we have four kingdoms. And that's where we're gonna
pend the rest of our time in this lecture on. So the first part we're gonna look at the bacteria and archaea domain, and some examples from those
species, from those domains specifically species that are
gonna come up again and again, when we study ecology
over the next few weeks. And the eukarya domain,
we've got four kingdoms plant, animal, fungi, protist, 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 arthropoda which is where the insects
and other crustaceans belong. 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
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, not ten thousand ten 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 it as hierarchy. It belongs to the aukarya
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 got the anthophyta and
then so on and so forth, I'm not a plant biologist, so I'm not even gonna 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. And it's not that if we
were where 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 one another, because they have the same, pretty much genetics and whatnot. Now, because there are so many species, we can't not even cover a,
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 gonna have quite
a few different examples, and you're gonna see several here, but just pay close
attention to the ones that, that I make mention of and point out, because those are the ones
that I'll not only test you on, but will carry on to subsequent lectures. So one of the things about bacteria and archaea that first confused us is they're both prokaryotic cells, okay? 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, "they pretty much behave mostly the same." Well, the more we investigated, the more we realized
that's not always the case. They have some substantial
differences in their genetics, as well as in their proteins,
in which they do it. As well as when we look at the ecosystems, they played 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. Well 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 gonna happen in you, but in simple cells like probiotic cells, this happens quite a bit. In fact, they have these
little regions called Sexpili 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
cross scene 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 probiotic cells lack. They don't have a nucleus, so they don't have a nuclear
envelope like you and I do, or that eukarya has which is one of the main
things that classifies them. They're particularly small about a 10th a 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
plasma 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 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 a glycogen and things of that sort
as the carbohydrate. So unlike plants, which make their cell
while purely out of silos and unlike fungi which make cell wall out of things like chitin, bacteria, they'll make their cell walls out of both carbohydrates
and protein, okay. 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 the, this molecular basis is peptidoglycan. Now we once thought that archaea also had the same cell 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 pseudopeptidoglycan. Because pseudo is kind of like fake or not the same, you know 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, okay. The peptidoglycan you're
gonna see that word pop up a couple times, over the next a week or so in terms of looking at
some of the similarities and differences between species. If I were to ask, you
know what plants and fungi and bacteria make 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 some species that though they don't use
the organelle chloroplasts 'cause remember chloroplast are the organelle that's plants use, as well as other organisms
use 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 domain that have the ability to
undergo photosynthesis, whereas to date, 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 Fila, they're very diverse, there are 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 robotic 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 pudding of
nitrogen such as nitrates like ammonia 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 what aspect of recycling nitrogen, but without these bacteria, we wouldn't have the
ecosystems that we have today. They are 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, 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 just be one large circle. Their cell walls made of peptidoglycan which 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 cross talk with other bacteria and
share that with them. They are also important for our food, the we use them in the
production of man of the things that we enjoy today. Vinegar, 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 is it 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 take. 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 rep, every time we think of bacteria, we always think of infection and diseases and things of that sort, but I wanna 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 were able to convert
nitrogen gas into ammonia and nitrates they're
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 of the 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
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 are 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 it's 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
blood stream, it can kill you. Now anthrax is another one that we have are a little scared of because that's really
what weaponize 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 things as
we've seen in the past. Because once they get introduced back into a biological organism, they're able to literally revert
back to their normal form, grow very rapidly, released their toxin, and it 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's transmitted virally, sometimes it's between the
actual bacteria themselves between these sexpili. 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 studied 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 Murcia. 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 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 our archaea are the probiotic cells that typically live in
extreme environments. Hence we call them extremophiles. So eextremophiles live in areas
that not many organisms can. And there are three main
types of extremophile that I'm gonna test you on
or that I want you to know. And these play various ecological roles in various parts of the world. Normally 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 going to find many organisms, but you do have these microorganisms living in this, in these areas because they're able to withstand the extreme salt concentrations that 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 environment, 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 gonna be able to live
in those hydrothermal vents that come up and create a
very acidic environment, a 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, 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 kinda keep them
nice and separate for testing. So it's all about the eukarya domain, which is one of the most
diverse group of organisms. And pretty much the thing that classifies eukarya domain, is every organism that
belongs to eukarya 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 Protis. Look at this, we don't know
what the hell we're doing, okay. - [Man] No. - [Narrator] What I really mean by this, is there are so, there's so much diversity
in the protest kingdom. There might be as many as
20 different kingdoms here. You could see that we're
already discovering some of these groupings or
branches through fila genetics, but here's the most interesting thing. If it's not a fungi animal or plant, we throw it into the protist
kingdom and I'm not kidding. So this is where we put things that are not very well defined
as a fungi, as an animal or as a plant, okay. So look at this branch I mean, it's just enormous because
you've got some protist 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 Nope, "the genetics are too
different and whatnot. "And they're not fungi." So let's start with the protists kingdom, extremely diverse. 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. It's not done by plants,
it's done and by protists. Think about it, our planets mostly covered in
water, 2/3 covered in water. These are 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
a key for the survival of many 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 protus 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 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 sea weed. It's kind of plant life,
but these aren't leaves. We call them blades. They are able to undergo photosynthesis and the buoyancy of the airfield pockets ultimately allows the plant to stretch up and be able to receive that sunlight. I mean, sunlight can
penetrate over a hundred feet into the water. And so you have a lot of
photosynthetic activity 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 as a plant. But green algae is a
photosynthetic algae or produce. Now, so this is definitely one of those that I'm gonna test you
on in general, algae. I'm not gonna make the distinction between gold, green and these
different types of algae. Now, if you look back on this right here, and that's where you can see
this group of a 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 protist
called dinoflagellates. These protist 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 muscles, and if you were to eat that, this is where you're going to
get that shellfish poisoning. Is if you eat them when they, 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 were also protists that ultimately excrete, this, and this is where we get the red tides. Diatoms are another type. These are interesting, if you've ever heard
of diatomaceous earth, they're essentially diatoms. 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 the seabed and form a lot of the composition of that. So if you were ever 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. It works really well for that because they don't like the, going over this area of
kind of glassy remnants of the cells. This was once classified as a fungi, but due to phylogenetics, we realize, hey they're
not, for number of reasons. Not only are their genetics
very 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 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. I usually talk about fungi
before plants anyway, but fungi are vital for the
stability of any ecosystem. Why? Because their main job
is decomposition, right? In any ecosystem, they
are the major recyclers. They live in the dirt in the roots trees, they live in these areas and they are gonna recycling
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 blocked the bacteria from making their cell wall. And from there, we've been able to drive
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 and making your own antibiotics,
you're gonna kill yourself. But we've been 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 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 fungies 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, 'cause this is what the
fun guy actually is. These filaments are all haploid, you remember what happened 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 main types together, we call them plus and minus there's no male and female fungi world. Maybe they consider
themselves that, but we don't. So the plus and minus male
mating species get together, fuse the haploid cells into a diploid cell that diploid cell creates the mushroom. And then it undergoes miosis,
creating the haploid spores that will then disperse
and spread that 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 a fungi that are connected together and
form almost look like roots. Okay, but these are the fungus, this is the actual fungus itself, okay. 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 sack
that undergoes meiosis and creates haploid spores. And that what is what
gets dispersed throughout to be able to spread the cells. So fungi actually reproduced
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 analogy
or fungus and 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 gonna get a lot of these discolorations
because of the pigments in the chlorophyll, and other pigments that are
necessary for photosynthesis. Well, what do the fungi do? Well, they protect the algae from it 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
get the fungi nutrients and the nutrient and the fungi
in turn protect the allergy. 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. Okay, so the adult cells of a fungi are haploid not diploid. They only become diploid
when they fuse together in preparation for sexual reproduction. They make their cell
wall out of chitin okay, man, 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 and 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. Their main 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 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 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. 'Cause there's just so much
to read about in your book as well as to go over. So plants, that plant
kingdom is very well defined. In fact, all plants are multicellular, we do not have any plants that
are single celled organisms. So they're all multicellular,
there are no single celled with a few exceptions, all plants are essentially
photosynthesizers okay. 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. Okay, so remember we
talked about the protist and being aquatic photosynthesizers, well plants are their
counterparts on land essentially for their ecosystem. So protist play a major role in a lot of aquatic ecosystems, plants play a huge role in
the terrestrial ecosystems on our planet. So also get some of the ways
in which we classify plants in some of the groups. There're actually four
major groups of plants. Now these are not, I'm going to necessarily test you on each individual phylum
and things of that sort. I remember we have the kingdom,
which is the plant kingdom, and then 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 say true mosses is because other plants
have the name moss in them like clubmoss and spike moss and whatnot, but they're not true mosses
as 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 clubmoss you'd be like, "Nope,
that's just the name of it, "it's not actually a moss." So more naming, you know
problems that scientists have. So the bryophytes are the
major group of organisms. Now they don't grow very tall, they're nonvascular 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. So they remain small, so when you look at a moss, this is a closeup version of them, but they don't grow very tall, okay. So mosses, liverworts, hornworts. These are examples of
the seedless nonvascular. 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 polen 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, which are with a high
amount of water and such. So those are what we call the
seedless nonvascular 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 all know about house
ferns and things of that sort ferns and their allies
are as they call them. This is where clubmosses and
other things come into play, which is why I'm not really
gonna bring in clubmosses on any examples, because it
just tends to confuse people. In fact, I tend to use the word bryophytes more often than not when describing the seedless nonvascular, 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 flow and redistribute it to
the rest of the cells where they can then use
that nutrients and those that energy produced
through photosynthesis. So ferns and their allies, these are the seedless vascular plants. Now gymnosperms these
are the seed vascular, however, there are non flowery. So they do encase their
sperm in pollen grains, they do produce seeds like pine trees. You can, if you look at the pine cones, you can actually see the seeds in them, but they're non flowery,
they don't produce flowers. And so therefore they
don't attract pollinators. They're also, if they're non flowering you don't have any fruit
production in that regard. Now there are vascular
just like the other plants, where they have 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, gingko plants and the like. Now when you look at
these phylogenetics here, and you can see that, you know there's a large
distribution of plants if 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 plant on our planet or series of plants on our planet. The most abundant plants are
the seed vascular flowery. Why do you think they're
the most abundant? And why would that make
them have the ability to reproduce more effectively? - [Crowd] Pollination. - [Instructor] 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 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 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 were the bryophytes or
the seed list nonvascular, the ferns are the seedless vascular. The pine trees are the gymnosperms are the seed vascular non flowering, and the angiosperms are the
seed vascular flowering plants. 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 are 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 chemoheterotrophic, which means there are
no photosynthesizers. Now there's always exceptions, there's like this, there's some sea slug that eats plants that
absorbs their chloroplasts and can do some photosynthesis. There's some strange things out there, but on the whole, all in
most are nonphotosynthetic. They're chemoheterotrophs which means they have to eat
other organisms to get energy, we cannot make it for ourselves with a few exceptions, all
animals are sexually reproducing. That is our mode of reproduction, but that's also what gives
us our selected 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. 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 and 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, okay. 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. There's just so much diversity and whatnot in this phylum right here. Now I am gonna go through
each of the phylum so you can get a good appreciation as far as what makes
up the animal kingdom. 'Cause as I mentioned, most of the time, when
people take animals, they think vertebrates
what I'm 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 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 of
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 show the "SpongeBob SquarePants," movie, for the peripheral for the sponge. But that's the first phylum here, periphery 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 are things like
jellyfish and the Hydra and the (indistinct) or 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. They are flat with various tapeworms and things of that sort. But these platy helmet, these, 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 muscles and whatnot. You even got some interesting ones that look very much like their ancestors? Like the nautilus, annelids
are essentially worms. Now, these are not like
the platyhelminthes where the platyhelminthes are flat worms, these were more roundworms. 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 the, for his fictional world. These tube worms reside in the sea and can actually hide down into the tubes when danger comes about, it's essentially how that was, nematodes were also
another type of a 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 exoskeleton 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 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 it's 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 die, that they're getting
better at it all the time, but there's just a wide variety
of things that we can learn. And know from these arthropods. Echinoderms, these are
things like sand dollars, sea urchins, star Fish, All right, and then we reach our phylum, the chordate 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 squirt and the lancelet 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 its the only mammal that lays eggs.
