hi this is Kim and this is video number two on the animals we have covered several animal FAS so far so let's review what we've covered we've covered the phm porifera which were the sponges nidaria which were the Anemones corals jellies Portuguese man of war Hydra we covered the flatworms which were platty helenes and we covered the round words round worbs which were the nematodes neota so again for each of those PHA you need to know the film name who's included any advancements in that group over the previous group and examples of characteristics that all animals in that group share so as we move on the body cavity is going to become extremely important and it is going to allow animals to get bigger and more complex so let's talk about what we mean by a body cavity also called a celum so let's start by drawing the FL flat worms who don't have a body cavity so they have three tissue layers the endoderm the ectoderm and the mesoderm but they don't have a space in which complex organs can be protected and develop so looking at platty helenes they are what is called asomate meaning no celum no body cavity and let's look at how that presents itself so right here in the middle of the animal is going to be the gut made of endoderm and then immediately rounding that gut with no space in between is going to be the mesoderm and this is going to be a crosssection of the worm sorry it should be symmetrical but it's not so no space this is just going to be completely filled in with mesoderm so the only space is the interior of the gut otherwise the mesoderm completely surrounds the gut and goes all the way to the body wall which is made of [Music] ectoderm so we would have a layer of ectoderm on the outside and these are the three colors that are typically used to represent these three different tissue layers so yellow is usually endoderm red is mesoderm and blue is ectoderm and you can see there's no space except for the interior of the gut what this means is these animals cannot develop complex organs because when the muscles of the body will all contract it's going to crush the organs so they really can't get very big and they can't get very complex I'm not going to take the time to completely fill this in but you get the point so this is the yellow is [Music] endoderm and this is the inside of the gut the red is mesoderm and the blue is ectoderm and the next group neota they are what's called pseudo cumate they have a pseudo what that means is once again using the same colors there is a gut led by endoderm and then there's a space called the pseudo celum outside of that space is a layer of mesoderm and then outside the mesoderm is going to be a layer of ectoderm so sorry I'm not doing this perfectly but I just want to paint a picture for you how this looks okay outside of that ectoderm that space between the endoderm and the mesoderm can be filled with fluid to create a hydrostatic skeleton and it can house some more complex organs than what we saw in the flat worms so I'm not going to go through the trouble of drawing I mean writing that because you already know from the previous that this space here this space is the pseudo and again the worms can fill that with water and they can have a little bit more complexity a true celome is going to happen as we get to the next organisms so the mollis so these are different PHA so FM molesa phm analita and philm arthropoda all have a true celome so they're what's called camate and here's what that looks like I'm switch back to thicker endoderm around the gut mesoderm this is where it gets a little trickier more mesoderm and then ectoderm this space is the seum the body cavity a true is completely surrounded by mesoderm organs can attach and be anchored to that mesoderm layer and now animals can get more I'm going to make a whole list for you of the advantages to having this seum to having this body cavity that's completely surrounded by mesoderm so advantages to having a celum a body cavity number one body muscles can contract without crushing the organs so when you move your body you have just think about your abdominal cavity and how it's surrounded by muscle but then there's this fluid filled space with your organs of your abdominal cavity anchored in place you can do sit-ups you can run you can jump you can stretch and it's not crushing your liver crushing your kidneys that's because of your body cavity it also means you have space to develop these complex organs sorry about that and anchor them in a protective way so they're not just floating around in there so now we start getting complex systems we can develop a digestive system more complex than previously excretory system to deal with waste circulatory system respiratory system reproductive system all because of this body Cav body cavity all because of this with this space in these more complex organ systems we're going to have better transportation of nutrients gases hormones waste products and now because of all this animals can get larger if you can more efficiently get nutrients to your tissues gases to your tissues you can have complex muscles that can contract without crushing your organs you can now get bigger so the first time we're going to be seeing some bigger organisms is mostly with the mollusks mollusks have a body cavity and if you've seen giant squid before you can you know that mollusk can get pretty big so let's just look at these pictures one more time I really wish that on this one I had used the fat marker to start with but no space at all in here this is an asomate organism the flat worms no body cavity the next is the pseudo celum there's a space there but it's not lined with mesoderm on both sides and then this is a true body cavity completely lined with mesoderm and the advantage is to having a body cavity I also want to just quickly review the three embryonic tissue layers and what what those can develop into and I'm just going to give you a short list of those so I'm going to start with the ectoderm sorry I saw fat pen the ectoderm which is shown in blue typically that outer layer that develops into the epidermis of the skin it develops into the lining of the mouth and anus so not the entire digestive tract that's going to be endoderm the cornea of your eye your nervous system and your teeth so obviously animals who don't have some of these structures doesn't develop into that okay mesoderm which is always represented in red I should have written ectoderm in blue mesoderm it can develop into elements of the skeletal system muscles the excitory system circulatory and lymphatic systems lymphatic system is an important part of your immune system your reproductive system comes from mesoderm and the reproductive system of all animals comes from mesoderm the dermis of your skin and lining of the body cavity which is very important okay and then finally endoderm always shown in yellow that is I'm going to write it in black now lining of the digestive tract except for the mouth and anus but your entire intestine stomach all of that is aligned with endoderm so lining of the gut um lining of the respiratory system lining of the excitatory system so lining of your bladder your ERS lining of the reproductive tract your liver your pancreas and your thyroid so that's not a complete list but it's just kind of gives you an idea of once you have three tissue layers and you have a body cavity animals can get a lot more complex okay so now let's move to our next fum so again going back we've had peripher nideria platal menes and nematoda so this is going to be our fifth animal philm and it's going to be phm molesa the mollusks this is an extremely large diverse group of animals in fact it has the SE it's the second largest group of animals on Earth meaning second largest group in terms of number of species and it's incredibly diverse it includes I'm going to show you pictures of these that includes kitens it includes all the B valves such as oysters clams scallops muscles it includes what are called the seop pods which are the squid octopus cuddlefish that's a u sorry about that that's CU U it includes the Nautilus and then some other groups it includes the gastropods which are snails and slugs and as you know these can be terrestrial meaning they live on land or they can be aquatic fresh water and salt water which is pretty crazy includes Barnacles limpets so a very diverse group of organisms they can get very large they have very complex nervous systems in some as you probably know the octopus in particular are very intelligent they can solve problems work puzzles learn so huge diversity in the mollis what do they all have in common well they share a basic body plan and that basic body plan includes a shell so all mlls have a shell even if it's been greatly reduced if you've ever made Camari or dissected a squid and in Biology class you know there's this little clear piece you pull out called the pen and that actually is the remnant of the shell they all have a structure called a foot and that foot is used for a variety of things it can be used for attachment to rocks or other surfaces it can be used for capturing prey defense obviously Locomotion for mating for holding eggs lots of different functions of the foot then they all have what's called a mantle and a mantle cavity I'm not really going to take the time to go in a lot of detail about the mantle and the mantle cavity but if you do take an organismal biology course at some point you will learn a lot about the mantle and the mantle cavity in the mollusks I just want to show you some pictures of mollusks but I want to really emphasize again they are cumate so they have a true celum a true body cavity and that's how they're able to develop this complexity and they can get very large very large octopus very large squid in particular so let's look at some examples of those here's a scallop these guys are filter feeders a lot of molets are filter feeders snail on land and then a sea snail this is a nautilus Nautilus are very amazing they have this really cool chambered shell kind of like a mini squid with a really cool shell this is actually a cuddlefish looks a lot like a squid an octopus you can see in the octopus the foot has really been reduced to just the the suckers on his legs and then if you look at something like a kiten if you've ever seen these in the tidal Zone in San Diego or any kind of tide pools they really are subject to wave action water moving in and out they need to adhere to the Rocks so they don't just get swept away and also at low tide being able to attach with that foot is going to keep them from drying out this guy's really camouflaged this is one of my f favorite class names in the mollusks pooper it means many plates and you can see that this animal has a lot of plates on its back I love this look at this giant snail is that crazy people keep these as pets really beautiful mollusk really beautiful giant clam these of course are a really important source of food not just for animals in the ocean but we eat them they're a big source of food for us you can see some of the complexity here in this B valve a heart a kidney muscles intestine mouth you can see where they show the foot and the mantle has gills for respiration lots of complexity there and then of course the seop pods very complex in fact the most intelligent invertebrates here's an octopus trying to open a bottle because there's a treat in there and they can learn how to do that okay philm molesa the next FM we're going to look at are the segmented worms and they also have a true body cavity and they are in philm analita the segmented worms so we've had the flat worms the round worms and now we have the segmented worms so they have a true celum so they are called cumate two two big advancements in the segmented worms one is segmentation segmentation is a big deal in animals because this is going to lead to specialization of body segments and the arthropods are really going to go wild with that they're also the first with what's called a closed circulatory system meaning it's not just fluid sloshing around it's actually contained in blood vessels they have blood vessels and they have a heart who does this include it includes the earthworms several different types of segmented U Marine worms and it includes leeches which are parasitic in fact what's interesting about leeches is they're what's called ectoparasites they live outside the host fleas and ticks are also ectoparasites the worms we looked at before were called endoparasites okay they live inside the host leeches are interesting because they are actually medicinal and they are still used today in medicine you knew they used to a long time ago if you had cold or flu they would put leeches on you to suck out the toxin they felt like you could suck out the bad blood and you would get better they're used today in micro surgery it can put leeches on you know if they're doing a surgery on your fingers or toes they can put leeches in there because leeches produce what's called herodin which is an anti-coagulant okay so let's think about it you're an ectoparasite and you're sucking blood from your host you don't want the blood clotting as it's coming into your your mouth parts so they produce this anti-coagulant so basically the mouth parts are getting blood that's not clotting no the clotting factor is not working so they actually Harvest this and make an anti-coagulant that can it's a actual drug that is given to patients sometimes after surgery but they're actually used in micro surgery for this reason too if they need to keep those tiny little capillaries open they'll let the leeches put that anti-coagulant into that area while they're working on it I'll just show you some quick pictures of anelids really segmentation is the big deal and it's the next group that are going to go wild with the segmentation so I'll show you those so here are the leeches here's some Marine worms at the top and of course the earthworm just want to show you some of the things in an earthworm that you probably didn't know about unless you did an earthworm dissection in high school biology but there's a centralized nervous control center called the brain they're are complex blood vessels mouth ferx esophagus is multiple Hearts male and female reproductive parts a nerve cord very complex this nephridium is involved in part of the excretory system so segmentation is going to allow these animals to develop even more complexity on top of the complexity they're getting because they have a true body cavity okay the next group of animals are the arthropods Vim arthropoda so let's go back to the notes I'm going to change color philm arthropoda these are the most numerous animals on Earth they live in virtually every ecosystem over 1 Milli milon known species the most numerous of which are the insects but let's talk about who this includes so it includes spiders ticks and mites which are all grouped together it includes the insects mipedes and centipedes it includes all the crustations so lobsters crabs um shrimp crayfish and then it includes the horseshoe crabs which are different normal crabs so huge diversity in the arthropods arthropoda this means joint arthro means joint and poda means feet jointed feet arthropods all have jointed appendages and really appendages are the big deal in the arthropods they have gone crazy with their append is a huge diversity of Form and Function let's talk about some of the functions of appendages in the arthropods obviously Locomotion and that Locomotion can take on so many different forms they can fly they can swim they can walk sensory especially the antenni and some groups of arthropods have multiple antenni defense if you have ever tried to pick up a lobster you know about the defensive structures that are appendages Fe eating capturing prey me go back to feeding for a second the mouth parts are actually considered appendages and they are so complex just looking at insect mouth Parts alone there's so much complexity there I love insect mouth Parts they're so interesting reproduction the actual mating holding eggs so lots of different functions of those appendages and really arthropods have just gone wild with that arthropods have an exoskeleton meaning the skeleton is on the outside and it's made partially of kiten remember kiten is also found in the cell walls of fungi so it's pretty interesting that arthropods which are animals have kiten that makes a part of their exoskeleton segmentation is a big deal and really they have specialized body segments and I'm going to show you an example of that when I show you the slides in a minute I'm going to give you a cool example of that and really complex mouth Parts like I had mentioned up up above really different feeding strategies especially in the insects so let's just quickly look at some examples of arthropods first I'm going to show you that just within the insects they are the most numerous about 80% of arthropods are insects and you can see most of those are beetles and then you can see you know flies butterflies Moss bees wasps ants this is a bee obviously which is an insect and if you look at how these body segments are specialized head thorax and abdomen the thorax is packed full of muscles and that's where the wings and the legs are so that thorax is going to be used for Locomotion whereas the head is where all the sensory functions are going to be located so looking at the head really everything the brain the eyes the mouth Parts everything sensory the antenna are all going to be in the head region then the thorax is for Locomotion so now that means if you can pack the thorax full of muscles all of the real um organs can be in the abdomen which is everything from the thorax back so this would be the abdomen and that's where the organs are so when this insect is flying or walking it's not Contracting muscles that are going to crush its organs it does have a body cavity so that's not a huge concern but also it's pretty cool that they can just pack this thorax full of mus muscles and that's really concentrated for Locomotion and then the head again everything sensory and nervous system so specialized body segments that's a big advancement in animals you can see here in the Crustaceans The Head and the thorax are combined into What's called the seph thorax seph means head so this is head and thorax together and then again the abdomen so the abdomen is going to be where the organs are and then sensory and Locomotion are going to be in the sephy thorax you can see they have antenna eyes you can see the gills and jointed feet arthropoda exoskeleton all those different traits of arthropods so in the next um video we're going to talk about chordates which includes the vertebrates but we do have one more invertebrate group left that are actually more closely related to us than all the other invertebrates and those are the echinoderms so we have one more phm left in the invertebrates and that's phm e kodada it means spiny Skin So EO means spiny and Derma is skin these are the spiny skinned animals this includes sand dollars sea urchins sea stars and brittle Stars what do they all have in common well they have this five body part plan that they all share and I'll show you a picture of that they actually have gone back to having radial symmetry so all of the organisms we've talked about starting with platy helenes leading up to this all have bilateral symmetry now we're going back to organisms that have radial symmetry which again means they're round in some way and you can have two halves that are mirror images by cutting this a number of different ways they have what's called a water vascular system where it's a system of tubes that fill with water to help them move and if you've ever seen a sea star moving very slowly in a tide pool you've seen that water vascular system at work and it's combined with what are called tube feet and those little tube feet are filled with water also so let's look at the ayog germs then I'm going to tell you one more thing about them oh I left off the C cucumbers in my list too so sea urchins sand dollars brittle star sea stars and SE cucumbers also so add that to your list SE cucumbers are so cool I love C cucumbers so you can see the five-part plan on the sea star he not only has five legs but he has five parts in the middle here a brittle star which is in a different class than the regular sea stars sea urchin which if you turn it over you can see the five parts there sand dollar 1 two 3 4 five and here's a picture of the water vascular system and the tube feet that fill with water for Locomotion I just want to tell you something else about the echinoderms though let's go back to this chart if you look at everyone we've looked at so far okay so starting with the sponges this is hard to read because it's pretty small so here are the sponges phym periphera no true tissues no germ layers meaning no endoderm ectoderm or mesoderm and then we start getting true tissue layers and that branches into those with just two k versus those with three and the only group that we are studying in this class that it has just two are the Nigerians and remember they also had radial symmetry okay then we get into those with three tissue layers so this is where that starts three tissue layers versus just two and then we Branch off into those that have a body cavity and those who don't so the only aate organism that we looked at with three tissue layers are the platy helenes then we get the pseudo and the other one we looked at were the nematodes and then finally a true celome and you can see it includes the mollusks the anelids and the arthropods it also includes the echinoderms and the cordat but you can see that there's one more Branch here a group called The protostomes and a group called the deuterostomes the protostomes include the mollusks analid and the arthropods whereas the deuterosomes include the echinoderms and the chordates I'm going to write that on paper for you they all have segmentation except for the Mala so segmentation have in the anelids the arthropods the kodm and the cordat but what's significant about the protostomes versus the D systems is how they develop embryologically and that's what makes us more closely related to the echinoderms than the other invertebrates chordates are more closely related to the echinoderms because they are all deuterostomes what does that mean so let's just quickly look at protostomes versus deuterostomes again the protostomes this includes mollis so Mesa analita and arthropoda and I really should have capitalized the first letter there but I didn't dter Dums this includes echinodermata and cordada the cordat are going to be covered in a different video that's going to be video number three what's different is first the pattern in which the cells start dividing and whether or not those cells have a fate for what type of cell they're going to become at what at the eight cell stage or not okay so in the protostomes it's what call it's called spiral cleavage because it's they're dividing in this spiral pattern okay versus radial cleavage also at the eight cell stage protostomes it's already been determined what type of cell those are going to become but in dudos it has not yet been determined the other thing that happens is as these cells start dividing dividing dividing they form a ball called the blastula the blastula is basically a ball of dividing cells and eventually an opening develops in that blastula whether that first opening becomes the mouth or the anus is the other difference between the protoo development pattern and the dudoso development pattern okay that first opening is called the blastopore and in the protostomes the blastopore becomes the mouth and in the dutters the blastopore becomes the anus so blastopore is that first opening and oops sorry I I just did it the opposite way the blastopore becomes the mouth in the protostomes and in the deuters it becomes the anus okay I'm going to go back to the notes and I'm going to write this down so you know exactly what you need to know okay let's go back to the notes protostomes versus deuterosomes the big difference is in how they develop embryologically so starting from that first cell the zygote how that zygote starts developing it divides divides divides it eventually forms a ball of cells called the blastula and the first opening is the blastopore pattern of cell division differs when determinant cell fate happens differs and you don't need to memorize which one is which but I do want you to know this what the blastopore becomes differs and in the protostomes blastopore becomes the mouth and in dudes the blastopore comes the anus and that is us so the first opening in that blastula is the blastopore who are the protostomes it's via molesa analita and arthropoda who are the deuterosomes T Fila echinodermata and cordada which is going to include us so that's all for video number two the next video number three is going to cover the chordates including the vertebrates which includes us