Chapter 8: Lower Invertebrates

in this video we are going to be going over chapter 8 the lower invertebrates here's some key Concepts that we will basically be discussing throughout the video but you can come back later and check them out so we are shifting gears from things that like photosynthesizer and early video earlier videos we talked about um different um things in the ocean and how the water moves currents things like that but now we're finally shifting over to animals in the ocean and animals are defined as things that are multicellular they have true cells and they don't have cell walls on their cells they can't make their own food so they rely on eating other things you can have both invertebrates or vertebrates meaning they do or don't have a backbone um although most marine animals are actually invertebrates now I know you're thinking but a ton have a backbone yeah but those tend to be the most iconic ones but but like what you see here are some sponges and things in the background that are all invertebrates so if you added up how many invertebrates there are there's actually a lot more invertebrates than vertebrates so the first one that we're going to be talking about are the sponges the sponges are in the phylum periphera and it's thought that long ago they were probably one of the first original animals to come about they are um asymmetrical meaning they just kind of free form grow in different directions they're Cecil and immobile meaning they don't move here's a good video by Deep Marine scenes facts on sponges for you to check out and see some good images and explanations of how they work but basically inside of a sponge they don't have any uh specialized tissue two areas but they do have specialized cells so we're going to explain some of those cells here so they have a cell called the collar cell and the color cell has a flagella on it that beats and helps the sponge circulate water so in this diagram the water is coming in the sponge and the flagella help push the water along and move it out through the osculum at the top so this brings in food and oxygen it also helps get rid of waste so there's a few different body forms that you see in sponges one is called askanoid which is pretty basic the cycanoid which is more feathery and then very complex looking is the lucanoid with each of these if you look at the blue arrows this represents the direction that water flows into the organism and again and out through the osculum you can see some like on the lucanoid have multiple exit points and then the koana sites are shown in Black those are going to be areas that have the flagella that push things along and then each of these in foldings are there because it helps move a larger volume of water and in the sponge is better able to get oxygen and food and other things that it needs so this is a collar cell up close with the flagella and the color on it and where it anchors to the main part of the sponge and how water circulates through a sponge out these different spaces here's a video by Professor Dave explains phylum periphera on sponges where you can look at that for more information um so these are obviously suspension or filter feeders they're obviously feeding by pushing things through they have pinocytes which is their skin along the outside the archaeocytes which are like an amoeba and it'll move through this whole Space repairing anything that's broken which is really cool and then of course they have the color cells with the flagella that we've already talked about um so reproduction can happen a couple different ways asexually it can happen by budding remember budding is like making a mini me where it just makes a tiny little version of itself that's sticking off and it's done very intentionally and then when it gets big enough it will break off that little bud and that it can grow um that little clone somewhere else right and then another type is called fragmentation fragmentation is where say there's a piece of damage where something bumps into it and a chunk a random chunk just gets broken off it can fragment and regenerate the rest of it or it can have sexual reproduction most or actually hermaphrodites where they have the male and the female parts they have the archaeocytes which are cells that can turn into anything um eggs and they make their eggs from that and then they make sperm no Shocker from their color cells so if we back up and look at their color cells it looks like oh yeah this could turn into a sperm and it does and that's ends up being the sperm and then the eggs come from the archaeocytes interesting once the little baby is formed it makes a planktonic amphiblastula and this little guy moves around and it actually has a ring-like area on it that is sensitive to light and helps it kind of Orient itself what's interesting is the adult version doesn't have that just when it's in its little planktonic state is it able to do that so sponges actually compete pretty hard with some other organisms like corals and bryzoans we're going to talk you know what corals are but Bray zones will talk about a little bit later in the chapter they're moss-like animals that grow in colonies and on rocks and kind of encrust on those things um so obviously sponges will want to grow on the same types of places so they have turf wars with corals and brazoons for that that perfect spot to grow a whole Little Colony so in order to get other organisms to go away they will actually produce chemicals that can kill competitors or they will actually bore down into corals interesting for predator prey relationships sponges are have something in them called spicules which for us would be like eating glass or fiberglass like these tiny tiny little gloss shards and so almost nothing can actually eat that and digest it but sea turtles are an example of something that can I think that sea turtles have like gut Linings like that is just made out of like hammers nails and anvils or something because they can digest literally anything so here is a picture of a hawksbill turtle eating a sponge and having no ill effects from that because of its amazing digestive system sponges also have symbiotic relationships remember that a symbiotic relationship just means that a relationship exists it doesn't mean it's good or bad and sometimes that term is misused in other videos or taught incorrectly so as symbiosis just means there is a relationship however there are some of those relationships are defined as mutualistic where it's good for both or commensalism where it's good for one and neither here nor there for for the other organism so some organisms will live inside of the canals of these sponges so one example of that is a shrimp that ends up going inside of a sponge when it's a tiny little baby with a male and a female go in there and they end up um growing and eating different things that come in using the sponges protection they'll eventually grow so big that they're locked inside of the sponge for the rest of their lives and then their eggs and sperm will actually come out through the canals like the osculum and float away and hopefully find another sponge because the parents are locked in the house forever here's a video by side show the shrimp and the sponge a deep sea love story that you can see more like videos of what that looks like it's super weird so sponges um I also said they will go down and bore into corals like this to find a hard surface and they'll just grow on top of the coral which kills that chunk of the coral so now we're going to shift to nidarians cnidarians are organisms with stinging cells like jellyfish or hydroids or corals or sea anemones and they all have um neetocytes which are stinging cells and they actually have nematosis which are spear-like stinging cells here's a video from Professor Dave explains he has a lot of videos so on this topic so I'm pointing out I think all of them eventually we get to all of them but it's a really good I believe six part series on these but this is phylum Nigeria part one intro into the broad characteristics and phylum cnidarian part two the class hydrozoa to check out so with the organization of cnidarians it's important to know like the body shape or what it looks like so they generally have a skin on the outside and a gastrodermis which are cells that line the gastro vascular cavity on the inside and then a mesoglia which is a jelly part and the majority is the mesoglia um on the inside which is where they get their name jellyfish but um they are what is called radially symmetrical meaning you could put this like divider down in lots of different directions and you would get an equal half on both sides It generally looks the same on the both sides so as you can get move this Orient this lots of different ways and you're going to get equivalent halves that's a strong theme of this chapter is understanding um that like body symmetry and how it works so I put a video by Professor Dave explains on body symmetry that he kind of goes over all of it in one quick video and so this is the polyp form and this one has just the tentacles around the mouth and this one is called the Medusa form and um it's like the classic umbrella shaped jellyfish that most people think of when they think of a jellyfish um so there are staining cells this is crazy so there's the staining cells are called nematocysts and I put a gif here of what that looks like but the nematosis actually like pop out with a trigger so when this lid gets opened up when it gets touched there's actually a little trigger here that pushes the whole Barb suddenly out and it injects the Venom just like having a hypodermic needle it's like an organism that has a trigger filled needle on it when it touches you and I have been studying or stung by jellyfish um hundreds of times times I've gotten hundreds of jellyfish stings with the work that I've done before it's not comfortable to have these this is a video by smarter everyday jellyfish stinging in microscope slow motion okay this is a really cool video they actually um got this footage from a jellyfish sting which is really cool and I recommend looking at it so here's just another close-up of what the opening looks like of the lid and the trigger cell and then this nematocyst that comes out so you can have um very dangerous stings from these one is called the Box jelly because it's very boxy so it's not a big shocker that it's in a group called The Cuba zoens but a box jelly can be fatal within three to 20 minutes um and this is called the irocondi this is a type of jellyfish that is very venomous and it's named after some Aboriginal people in Australia and that's one of the places where you can find it I just have to give a shout out to this nudie here nudabranks are one of my favorites and this is one of my favorite nudies this is a blue Glaucus or the blue sea dragon so this is a type of nude rank that eats it actually eats the Portuguese man of war and then incorporates the Venom into its own body and it's just the goat of all nudibranchlic it's just really cool um looking so um there's different types of cnidarians besides that one is the hydrazoans and Hydra are Colonial and they actually have a joint like stomach area where they will share Foods so they have the gastrozoids that capture food and the gonan ganangium that serves for reproduction so they also make a calcium skeleton and some groups of them most of them are Cecil but some of them will actually form these floating colonies and in order to float they need different members to do different things so some of them reproduce some catch fish some will act as bladders and they'll blow up their cells just with air so that they can stay floating for the colony crazy thing is that Hydra which is a common name for hydro zones Hydra are actually considered Immortal because they can take their stem cells and regenerate um stem cells so most organisms have limited stem cells a stem cell is a cool cell that can turn into anything you need it to turn into so stem cells are awesome that way because they can their their possibilities are unlimited for for your body right but you only have a certain number of stem cells but not Hydra because when their stem cells are low they can just build more stem cells so they're basically Immortal and then interesting their cells don't age whereas we have a number of things about ourselves that they age over time but Hydra do not so another nidarian type is a jellyfish so I put a cool picture of a golden jellyfish that I think is really gorgeous that lives in Palau um the normal or most commonly thought of form of a jellyfish is a Medusa because it can't swim really well and you might look at this and be like I think it swims fine but it doesn't matter people have decided that it can't swim very well so it is jellyfish are considered planktonic um and so they are considered a plankton they do have photoreceptors tend to like it in the dark and they tend to shy away from the light here's a video by Professor Dave explains phylum Nigeria part 5 anthazoa and here is the same from the same series um phylum nydaria part 4 class Cuba zoa that will go over some of those um so a box jellyfish we already said is the cubazoa they are bell-shaped they're compared to other jellyfish these ones are stronger swimmers they live in tropical spaces they're voracious Predators especially a fish so this is a box jelly catching a tiny little baby fish and kind of so what it's doing to this fish here is it's injected it's venom and then it that will cause the fish to have muscle spasms which you can see here eventually that will cause the heart to stop and then the jellyfish can digest the fish so this is another video by Professor Dave explains phylum Nigeria part three um that goes over a few more jellyfish so anthaz Owens um got their name because they look like flowers so it's like flower animal is what its name is and if you look at them they kind kind of are flowery so this is sea anemones corals and gorgonians um we're gonna talk about sea anemones first and this is obviously a coral but this is an anemone over here and enemies are benthic meaning they live on the bottom of the ocean but um a lot of times you can find them in very shallow places though they can live deep as well um they tend to be Cecil but what's crazy is they can actually move their base around and find new places to go in many cases if they want to so corals are really one of like near and dear to my heart lots of people have a soft spot for corals they just love them and we're going to spend a few minutes just talking about them here so they are actually a type of polyp that excretes a skeleton so if you look at these guys here in this close-up they look a lot like a jellyfish Medusa and they just closed up in this GIF but they'll open right back up they look like a jellyfish and they are a distant cousin of jellyfish and um for their life history they were almost like jellyfish that like decided hey we don't want to be just planktonic floating around we want to stop and build a hard calcium carbonate skeleton and move all of our relatives around us so it's you when you think about a coral you can think about a bunch of like tiny little upside down jellyfish that have like glued themselves there with calcium carbonate all over so it really is a lot of people look at corals and they're like that's just a rock it's not it's a many many many um it's a whole colony of small organisms living together and if you rub up on Coral and stuff and get injured by it a lot of times it can be more painful than just getting scratched by a rock because it does have a stinging property in many cases just like a jellyfish so these guys by making these Rocky um Rocky skeletons for themselves they end up actually being a reef building type of creature that helps other organisms have a space to live so one type of coral that people don't even know exists in many cases are the soft corals So Soft corals um do have colonies um sort of like plants and I put two that I really like seeing in Southern California one is called the sea pen that when you um go diving here in Southern California you can often see these this is you know some people think southern California doesn't have Coral but we do and here's one of our soft corals and then this is another Coral called the sea panzan when you see it on the ocean floor it looks like this it doesn't look like much they're not very big um here's someone holding one of them here but what's so cool is because they are a coral um they have a they some like jellyfish relatives have bioluminescent properties and this is called a sea pansy that actually does have the bioluminescent properties this is a video by golf specimen Aquarium sea pansy glow and I highly recommend you check it out what it shows is at night when you go back if you are lucky to find one of these wherever you touch it it will light up and glow in that space like wherever it is touched um you activate it and you don't want to do it too much because then it's a living creature but that's what it is capable of doing and it's really really cool so um for Nutri nutrition and digestion they do have a gastrovascular tissue and cavity kind of gross their um the same part for taking in food is used for Waste as well so it's like having your food come in your mouth and out of your mouth at the end which is a little bit gross they um lots of them are suspension feeders but of course you know like jellyfish and box jellies that we just went over are carnivorous sea anemones will generally feed on invertebrates and just floating things in the water but Stony corals get the majority of their food from a symbiotic relationship that they have with zozantheli and just because this is so so important to what is going on in our coral reefs I need to press pause here for a minute and just take a minute to talk to you about this very very important relationship that not that many people know the details of so corals if I'm zooming in on it you know it looks like a polyp we just talked about that and here's like a really close-in picture of what a couple of coral polyps look like and if you look at them really closely you'll see that at least the outside Fringe of these ones are kind of like clear white translucent-ish right they don't have very much color and um corals don't have much natural color or any at all they just are clear white translucent-ish and also Coral over time has lost its evolutionary ability to make enough food for itself so like many many many organisms it takes on um other organisms in a mutualistic relationship where they both can benefit so Coral basically says hey I have a hard um cavity that's empty I'll take on a renter that can pay me in food so it actually takes this organism called zozantheli and zosantheli um is actually very brightly colorful and whatever color moves into the coral that ends up being the color of the coral so some Coral have a relationship with like a pink zosanthelier orange zosantheli or bright bright pink or purple or whatever color that it is that now when they take in that zozanthelian concentrate it that will appear to be the color of the coral is actually the zozantheli that lives inside of it so so Sam feli has the word um zoo in the beginning and zoo or Zoo means um animal so it's a plankton that um digests like an animal but it actually photosynthesizes like a plant so it goes and lives inside of the coral and it uses the sunlight to turn that sunlight into food and it gets plenty of food for itself and it's actually capable of passing a lot of the food for the coral like I said earlier Coral can't feed itself in fact it's such a bad and dire situation the coral can only make about 25 of its own food depending on the species so it relies on this zosantheli for about 75 percent of its food so it's kind of a lot and it's really important that the zozanthal you're there well also we talked about it's like an animal so it digests even though it's photosynthesizing it's digesting food like an animal and creating waste and like we talked about that waste has to go out through the top of the coral and the coral doesn't have a good method for getting rid of it but it roughly can get rid of enough with the currents washing through to make it okay except the oceans have gotten a lot warmer um the ozone is like thinner all over and the light coming in is more intense and the water is warmer on these zozantheli so it's causing a lot of these zosantheli to actually over photosynthesize and over respirate and make too much waste so they're generating so much waste that the coral starts to get septic and um the coral is just like you're a bad renter you used to pay me but now you just have waste and garbage and sewage everywhere you need to leave and so the coral actually expels the zozanthelli and kicks it out and it kicks out the zozan felly and then the coral is there stuck with this sludgy waist and it can actually be bright yellow at first when this happens from this septic like waste that's inside um eventually that'll get washed out by currents but now think about it the coral does not have enough food to feed itself plus it's just been a wash with all of this septic septic um waste and so the coral is very sick but Additionally the coral has also lost its color because remember it was the zosantheli that gave the coral its color so now the coral is back to this white translucent color and so it's said to be bleached and so when you see a coral that it's bleached it's very very very stressed because it doesn't have the right amount of food and within about two weeks to a month on only 25 food it will die and then also remember that during this time there's a lot of other organisms like tons of other organisms like algae or like we talked about earlier sponges whatever that will all want to move in and take the space of that Coral so it's not only stressed and has sepsis and it's not getting the right amount of food but all these other organisms that have wanted to compete like for space now see it as an easy target to come in and Target it so a bleached Coral can come back and can get restored if conditions get better but um it is tough it's tough to do that because you've got about a two-week window before the coral is so far gone that it dies and when it dies it will actually very rapidly you would think the skeleton would just hold and be there in bright and beautiful and white even though it's dead it would still be pretty but it doesn't it turns into Coral Rubble like really rapidly I actually have a video here um that you can check out where I'm doing a swim up in Hawaii of a space that this um space has some good living Coral but it also has some very dead coral and you can see it in the video if you check it out later um some of it is totally alive but others spots you can see algae and things growing on it this is a very stressed Coral wall and what I heard was that there was a really really bad storm that had hit it about a year earlier um and so it's in rough shape and at the end you can see I just pick up some of the coral Rubble where it's just totally dead and it's it's a huge bummer um this is a video by Colette Ben Sultan living ocean foundations Coral what do they eat that explains the process that I just did um but a little differently and with good images and then here's a video by Deep Marine scenes facts corals and coral reefs if you have to pick an order I would say watch this one first and then watch the Khaled Ben Sultan second so I think this is the part where I go up and just kind of show you that this is all Rubble that's all just totally dead coral going all the way up that wall and what it looks like to have that it's just really sad and something you generally just hate to see so hydrazone's um reproduce because now we're going to talk about reproduction of these organisms they have a polyp colony and the polyps are actually their asexual stage and they will break off the tops of these and that will be the Medusa the Medusa can have sperm or egg and then that will get fertilized um with each other that's their sexual stage and that um fertilized Aid will turn into a planular larva which will swim around until it finds a place to settle and make a polyp the scyphozoans this is like a moon jelly is pretty um characteristic of the whole group and so this is a good drawing of what moon jelly replication looks like they also have the polyps stage but interesting they make this like Tower of medusas and then they will just break off a chunk of medusas or maybe just one but sometimes they'll release like three or four all at once and then the medusas will float around male female until they fertilize an egg and make the planuler larvae same thing till it settles here's a video by ocean wise ever wondered how baby jellyfish enter the world that shows this planular larvae it's only like a minute long um it shows this Tower of Medusa's breaking off and it's just interesting so anthaz Owens remember anthazoins are the flower-like ones so that's anemones or corals um they have asexual reproduction where a part breaks off but the bottom disc is still attached so um in another video I show like an anchor that a cruise ship dropped on um coral and the anchor is dragging it along and those corals when you find broken up corals when you're scuba diving you can help save them by just doing what you see here you don't need a cage just as long as they have that bottom disc on them you can put it upright in an upright position and that bottom disc can um affix to a new substrate hopefully the substrate is like hard not Sandy and they can start to reattach themselves you can also have um a fission where peace breaks off like it fragments or you can have budding where it does grow a little mini me and then and then it sloughs off and makes a new clone um you can also have sexual reproduction uh where male and female sperm and eggs are released in the water column until they fertilize and then it'll form a planular larva which will swim around and make a new Little Colony okay so um the ecological relationship of cnidarians and the role that they play here's a video that shows you what I want to talk to you about next the video by National Geographic see a sea turtle devour a jellyfish like spaghetti um going along with the theme that sea turtles have digestive systems of Steel they are crazy predators of jellyfish so this is I think a green sea turtle here um eating a jellyfish and they will just rip it apart this is just a one or two minute video that I recommend checking out uh because it shows it better than it shows in this GIF but in this gift you can kind of see it the sea turtle will actually come up to the jellyfish and because they're only vulnerable part is their eyes often they will close their eyes and then they will use their friend um leg to kind of push away or paddle away the jellyfish in One Direction while their mouth rips it off in the other direction and they just tear them apart like spaghetti so it becomes an important food source that way um other ecological relationships of cnidarians is like our corals make very important habitats for other organisms it's very difficult to see in this picture but I had a lot to put on this slide um this is a sea turtle sleeping under a coral and this is a shark swimming under like little reef shark swimming sleeping under the coral there's a large number of organisms that not only use this as their home these fish have specific shapes to Dart in and out of the coral for safety and to use it as their home so many organisms rely on corals um it's estimated that Coral only makes up a tiny fraction of the world's oceans but when scientists have tried to estimate how many organisms at one point or another rely on Coral either for food or for safety or to raise their young and be a nursery for their young it's something like 25 of the organisms in the ocean rely on Coral at some point in their life history and here you can and see that there are certain fish that are even adapted with very tight little mouth Parts because they just swim around all day pecking at the coral eating the tiny little living polyps so they rely on eating polyps all day and that type of organism is called a corellivore and just like a carnivore eats meat or an herbivore eats plants Corella Flores specialize in eating Coral specifically so a large number of organisms rely on them then there's also a lot of symbiotic relationships remember symbiotic relationships just mean that there is a relationship it doesn't mean if it's good or bad um here's an interesting relationship with Portuguese man of war and the Portuguese man of war fish so the Portuguese man of war fish is a very intense little fish that happens to be 10 times more resistant to portuguese man of war toxins than other fish and it just swims along with the Portuguese man of war eating its gonads like its sex organs and eating its tentacles as it moves along um and unlike anemones or like clownfish around an enemies clownfish will secrete a mucus on themselves so they're not as bothered by the stinging cells this fish does not have that this fish instead has lots of extra vertebrates vertebrae that make it super agile and it will actually just constantly be darting away and avoiding the um stings of the Portuguese man of war but if it does get stung it actually has its own anti-venom too so it just swims along here eating its gonads and tentacles as it moves along um so interesting relationship another one is that um in sponges specifically or hermit crabs hermit crabs with anemones some of them will actually put anemones on their shell and the Anemones will get free food from the crab that after it nibbles on things and the anatomies give the crab protection so that would be a good mutualistic relationship this is a video that shows that by Blue World TV incredible footage of a hermit crab this hermit crab is actually changing its shell and when it changes and goes to a larger shell it picks off the Anemones and puts it on the new shell to take it with it totally crazy this is a video by coral reef 101 from National Geographic that you can look up as well and then here are just a few really good videos also from Professor Dave explains nidophoric home jellies also Professor Dave phylum Nigeria part 6 on coral reefs and a video by National Geographic world's deadliest comb jellies that's really interesting so now moving away from jellies and their stinging cells are the comb jellies these guys look like jellyfish and they would scare you like crazy with their bioluminescence but they actually lack stinging cells all together they are planktonic just floating around they're nearly transparent they have a status bubble inside of them that helps Orient them like up down and helps them figure out how to move or where to go they're for digestion and nutrition they tend to eat plankton larva fish fish eggs they have something called a collar blast which is a sticky adhesive cell that they use to capture their prey and here's a video by Alvaro megado swallowed holocome jelly praying on another comb jelly so you can actually see the calm jelly eat another one and then slowly how it's digested into little bits because it's transparent so you can see right through it for reproduction they are mostly hermaphroditic where they have male and female parts and those eventually will find each other and grow into a full adult here's a deep Marine Seas scenes facts that comb jelly tenofora where it talks about that a little bit more okay so with bilateral symmetry since we talked about um body plans and how we we covered La radial symmetry this is called bilateral symmetry so bilateral symmetry you can't just cut it in every direction and have equal parts there's one distinct way that this can be cut into two and usually organisms that have this tend to have um a concentrated a concentrated region that you would end up calling the head of the organism so the first um bilaterally symmetrical animal we're going to talk about is the flatworms and there's the turbularians and the flukes and the tapeworms and we'll go into a little bit more detail with them here here's a video from Deep Marine scenes facts Marine flat worms and you can see what they look like and how they move they're mostly on the bottom um dwellers and they live in the tiny spaces in between sand usually as a way to eat they have sensory receptors to detect light or chemicals or movements or maintain balance there's also some that live in the in side of other organisms so for reproduction this is really really crazy they actually reproduce asexually and their hermaphroditic when they have sexual reproduction okay this is the crazy part both of them have a penis and a vagina for mating with each other at the same time crazy their penis is like a sword and it has two prongs to it so here's two in this GIF and the gift does not do this mating process justice but these are two um flatworms that have found each other and they are going to fight each other and try to stab each other with their two-pronged penis when one of them stabs the other one with their two pronged penis you just lost and now you got impregnated and then that the other one will go away the winner goes away the loser now gets pregnant with all of the eggs and has to use their body um strength and energy to go towards growing and and caring for those those eggs while it's in its body so the organisms don't want to lose this battle they don't want to be the one that got stabbed so um while turbulyrians produce just a few eggs there are parasitic flatworms that produce 10 to 100 000 times more eggs then um the turbularians and obviously it it's parasitic that's kind of disgusting and it just goes out there and it's hoping to make it in its way inside of another organism so it can grow in it okay if you are interested in the um mating of flatworms here's a video by BBC Earth meet the penis fencing flatworm that goes into video detail of what this fencing fight joust looks like and it's really intense um okay so in ecology what is the role of flatworms well um they basically can cycle nutrients around and change help it to change forms the it eats other things other things eat it there's also in on a gross side they are parasitic some of them can be parasitic and so because they're a parasite and they're living in a host like um flatworms will have or I'm sorry um sperm whales for instance can have a tapeworm that is 30 meters long 30 meters long inside of them and that obviously makes the whale a lot less fit and it could get it could die because of that but then its body could be eaten by other things and so it's cycling nutrients still not my favorite way to go okay so um there are also ribbon worms ribbon worms are benthic they have external fertilization they are carnivores that have this crazy proboscis a proboscis is almost like a tongue that goes out and grabs food and here's a gif of what that looks like but the next gif is even better this looks like it would be fake right here but it's totally not this is a ribbon worm throwing out its proboscis which is effectively used like a web to capture prey it's a thing of my nightmares um so they can be important in the ecosystem because they make Burrows they cycle nutrients they're abandoned Burrows can serve as habitat and things like that okay so we're gonna switch to lofophoreaids which not that much is known on these and we're gonna go through them pretty rapidly the first one that I want to talk about is the um foreignids foreignids have a tube that they live in that they secrete of protein or chitin um they actually catch Plankton and dead and decaying matter that is floating nearby them here is one form that we see in Southern California called the California horseshoe worm and you can see why it's called the Horseshoe worm um they can produce sexually or asexually and they have a planktonic stage this is kind of what it can look like um this is a video by Alvaro megado the Horseshoe worm um for Anita that you can check out and then we're going to talk about bryz Owens so these earlier in this video I said they compete with sponges for space and that's because they live on colonies rocks shells algae Mangrove um they can sometimes they're they are very very abundant and found all over the place which it makes them important in the in the food chain because lots of other organisms will eat them they're also planktonic and most are hermaphrodites um the brachial pods um our benthic they live on the bottom these guys have two different shells so the top shell is a different shape than the bottom shell so if you think of like mollusks or bivalves um you might think oh that's just like like a mollusk or a bivalve like a clam but it's not because they have different shaped two different shaped cells they also have a flesh fleshy stock that they put into the sand to help them be upright they eat dead into cane matter in different algaes different they have different Sexes with a larva and a planktonic stage and their Plankton will eventually settle after like a day and be a grown-up this is a video um by the paleontology Association brachiopods small But Mighty that kind of goes into more detail on them so as a group these guys um lofophorates as a whole are filter your feeders and I like I said they do feed a lot of organisms they are somewhat disliked by ships a lot of times because they'll grow on whatever they can find and because they're so abundant they tend to grow on the bottoms of ships making them kind of slimy and they're part of what is called the felling Community where they are not appreciated um by the boating community so that is our chapter on Lower invertebrates I hope you grew an appreciation from them it's everything from sponges to corals and they're such an important important part of our marine ecosystem

in this video we are going to be going over chapter 8 the lower invertebrates here&#39;s some key Concepts that we will basically be discussing throughout the video but you can come back later and check them out so we are shifting gears from things that like photosynthesizer and early video earlier videos we talked about um different um things in the ocean and how the water moves currents things like that but now we&#39;re finally shifting over to animals in the ocean and animals are defined as things that are multicellular they have true cells and they don&#39;t have cell walls on their cells they can&#39;t make their own food so they rely on eating other things you can have both invertebrates or vertebrates meaning they do or don&#39;t have a backbone um although most marine animals are actually invertebrates now I know you&#39;re thinking but a ton have a backbone yeah but those tend to be the most iconic ones but but like what you see here are some sponges and things in the background that are all invertebrates so if you added up how many invertebrates there are there&#39;s actually a lot more invertebrates than vertebrates so the first one that we&#39;re going to be talking about are the sponges the sponges are in the phylum periphera and it&#39;s thought that long ago they were probably one of the first original animals to come about they are um asymmetrical meaning they just kind of free form grow in different directions they&#39;re Cecil and immobile meaning they don&#39;t move here&#39;s a good video by Deep Marine scenes facts on sponges for you to check out and see some good images and explanations of how they work but basically inside of a sponge they don&#39;t have any uh specialized tissue two areas but they do have specialized cells so we&#39;re going to explain some of those cells here so they have a cell called the collar cell and the color cell has a flagella on it that beats and helps the sponge circulate water so in this diagram the water is coming in the sponge and the flagella help push the water along and move it out through the osculum at the top so this brings in food and oxygen it also helps get rid of waste so there&#39;s a few different body forms that you see in sponges one is called askanoid which is pretty basic the cycanoid which is more feathery and then very complex looking is the lucanoid with each of these if you look at the blue arrows this represents the direction that water flows into the organism and again and out through the osculum you can see some like on the lucanoid have multiple exit points and then the koana sites are shown in Black those are going to be areas that have the flagella that push things along and then each of these in foldings are there because it helps move a larger volume of water and in the sponge is better able to get oxygen and food and other things that it needs so this is a collar cell up close with the flagella and the color on it and where it anchors to the main part of the sponge and how water circulates through a sponge out these different spaces here&#39;s a video by Professor Dave explains phylum periphera on sponges where you can look at that for more information um so these are obviously suspension or filter feeders they&#39;re obviously feeding by pushing things through they have pinocytes which is their skin along the outside the archaeocytes which are like an amoeba and it&#39;ll move through this whole Space repairing anything that&#39;s broken which is really cool and then of course they have the color cells with the flagella that we&#39;ve already talked about um so reproduction can happen a couple different ways asexually it can happen by budding remember budding is like making a mini me where it just makes a tiny little version of itself that&#39;s sticking off and it&#39;s done very intentionally and then when it gets big enough it will break off that little bud and that it can grow um that little clone somewhere else right and then another type is called fragmentation fragmentation is where say there&#39;s a piece of damage where something bumps into it and a chunk a random chunk just gets broken off it can fragment and regenerate the rest of it or it can have sexual reproduction most or actually hermaphrodites where they have the male and the female parts they have the archaeocytes which are cells that can turn into anything um eggs and they make their eggs from that and then they make sperm no Shocker from their color cells so if we back up and look at their color cells it looks like oh yeah this could turn into a sperm and it does and that&#39;s ends up being the sperm and then the eggs come from the archaeocytes interesting once the little baby is formed it makes a planktonic amphiblastula and this little guy moves around and it actually has a ring-like area on it that is sensitive to light and helps it kind of Orient itself what&#39;s interesting is the adult version doesn&#39;t have that just when it&#39;s in its little planktonic state is it able to do that so sponges actually compete pretty hard with some other organisms like corals and bryzoans we&#39;re going to talk you know what corals are but Bray zones will talk about a little bit later in the chapter they&#39;re moss-like animals that grow in colonies and on rocks and kind of encrust on those things um so obviously sponges will want to grow on the same types of places so they have turf wars with corals and brazoons for that that perfect spot to grow a whole Little Colony so in order to get other organisms to go away they will actually produce chemicals that can kill competitors or they will actually bore down into corals interesting for predator prey relationships sponges are have something in them called spicules which for us would be like eating glass or fiberglass like these tiny tiny little gloss shards and so almost nothing can actually eat that and digest it but sea turtles are an example of something that can I think that sea turtles have like gut Linings like that is just made out of like hammers nails and anvils or something because they can digest literally anything so here is a picture of a hawksbill turtle eating a sponge and having no ill effects from that because of its amazing digestive system sponges also have symbiotic relationships remember that a symbiotic relationship just means that a relationship exists it doesn&#39;t mean it&#39;s good or bad and sometimes that term is misused in other videos or taught incorrectly so as symbiosis just means there is a relationship however there are some of those relationships are defined as mutualistic where it&#39;s good for both or commensalism where it&#39;s good for one and neither here nor there for for the other organism so some organisms will live inside of the canals of these sponges so one example of that is a shrimp that ends up going inside of a sponge when it&#39;s a tiny little baby with a male and a female go in there and they end up um growing and eating different things that come in using the sponges protection they&#39;ll eventually grow so big that they&#39;re locked inside of the sponge for the rest of their lives and then their eggs and sperm will actually come out through the canals like the osculum and float away and hopefully find another sponge because the parents are locked in the house forever here&#39;s a video by side show the shrimp and the sponge a deep sea love story that you can see more like videos of what that looks like it&#39;s super weird so sponges um I also said they will go down and bore into corals like this to find a hard surface and they&#39;ll just grow on top of the coral which kills that chunk of the coral so now we&#39;re going to shift to nidarians cnidarians are organisms with stinging cells like jellyfish or hydroids or corals or sea anemones and they all have um neetocytes which are stinging cells and they actually have nematosis which are spear-like stinging cells here&#39;s a video from Professor Dave explains he has a lot of videos so on this topic so I&#39;m pointing out I think all of them eventually we get to all of them but it&#39;s a really good I believe six part series on these but this is phylum Nigeria part one intro into the broad characteristics and phylum cnidarian part two the class hydrozoa to check out so with the organization of cnidarians it&#39;s important to know like the body shape or what it looks like so they generally have a skin on the outside and a gastrodermis which are cells that line the gastro vascular cavity on the inside and then a mesoglia which is a jelly part and the majority is the mesoglia um on the inside which is where they get their name jellyfish but um they are what is called radially symmetrical meaning you could put this like divider down in lots of different directions and you would get an equal half on both sides It generally looks the same on the both sides so as you can get move this Orient this lots of different ways and you&#39;re going to get equivalent halves that&#39;s a strong theme of this chapter is understanding um that like body symmetry and how it works so I put a video by Professor Dave explains on body symmetry that he kind of goes over all of it in one quick video and so this is the polyp form and this one has just the tentacles around the mouth and this one is called the Medusa form and um it&#39;s like the classic umbrella shaped jellyfish that most people think of when they think of a jellyfish um so there are staining cells this is crazy so there&#39;s the staining cells are called nematocysts and I put a gif here of what that looks like but the nematosis actually like pop out with a trigger so when this lid gets opened up when it gets touched there&#39;s actually a little trigger here that pushes the whole Barb suddenly out and it injects the Venom just like having a hypodermic needle it&#39;s like an organism that has a trigger filled needle on it when it touches you and I have been studying or stung by jellyfish um hundreds of times times I&#39;ve gotten hundreds of jellyfish stings with the work that I&#39;ve done before it&#39;s not comfortable to have these this is a video by smarter everyday jellyfish stinging in microscope slow motion okay this is a really cool video they actually um got this footage from a jellyfish sting which is really cool and I recommend looking at it so here&#39;s just another close-up of what the opening looks like of the lid and the trigger cell and then this nematocyst that comes out so you can have um very dangerous stings from these one is called the Box jelly because it&#39;s very boxy so it&#39;s not a big shocker that it&#39;s in a group called The Cuba zoens but a box jelly can be fatal within three to 20 minutes um and this is called the irocondi this is a type of jellyfish that is very venomous and it&#39;s named after some Aboriginal people in Australia and that&#39;s one of the places where you can find it I just have to give a shout out to this nudie here nudabranks are one of my favorites and this is one of my favorite nudies this is a blue Glaucus or the blue sea dragon so this is a type of nude rank that eats it actually eats the Portuguese man of war and then incorporates the Venom into its own body and it&#39;s just the goat of all nudibranchlic it&#39;s just really cool um looking so um there&#39;s different types of cnidarians besides that one is the hydrazoans and Hydra are Colonial and they actually have a joint like stomach area where they will share Foods so they have the gastrozoids that capture food and the gonan ganangium that serves for reproduction so they also make a calcium skeleton and some groups of them most of them are Cecil but some of them will actually form these floating colonies and in order to float they need different members to do different things so some of them reproduce some catch fish some will act as bladders and they&#39;ll blow up their cells just with air so that they can stay floating for the colony crazy thing is that Hydra which is a common name for hydro zones Hydra are actually considered Immortal because they can take their stem cells and regenerate um stem cells so most organisms have limited stem cells a stem cell is a cool cell that can turn into anything you need it to turn into so stem cells are awesome that way because they can their their possibilities are unlimited for for your body right but you only have a certain number of stem cells but not Hydra because when their stem cells are low they can just build more stem cells so they&#39;re basically Immortal and then interesting their cells don&#39;t age whereas we have a number of things about ourselves that they age over time but Hydra do not so another nidarian type is a jellyfish so I put a cool picture of a golden jellyfish that I think is really gorgeous that lives in Palau um the normal or most commonly thought of form of a jellyfish is a Medusa because it can&#39;t swim really well and you might look at this and be like I think it swims fine but it doesn&#39;t matter people have decided that it can&#39;t swim very well so it is jellyfish are considered planktonic um and so they are considered a plankton they do have photoreceptors tend to like it in the dark and they tend to shy away from the light here&#39;s a video by Professor Dave explains phylum Nigeria part 5 anthazoa and here is the same from the same series um phylum nydaria part 4 class Cuba zoa that will go over some of those um so a box jellyfish we already said is the cubazoa they are bell-shaped they&#39;re compared to other jellyfish these ones are stronger swimmers they live in tropical spaces they&#39;re voracious Predators especially a fish so this is a box jelly catching a tiny little baby fish and kind of so what it&#39;s doing to this fish here is it&#39;s injected it&#39;s venom and then it that will cause the fish to have muscle spasms which you can see here eventually that will cause the heart to stop and then the jellyfish can digest the fish so this is another video by Professor Dave explains phylum Nigeria part three um that goes over a few more jellyfish so anthaz Owens um got their name because they look like flowers so it&#39;s like flower animal is what its name is and if you look at them they kind kind of are flowery so this is sea anemones corals and gorgonians um we&#39;re gonna talk about sea anemones first and this is obviously a coral but this is an anemone over here and enemies are benthic meaning they live on the bottom of the ocean but um a lot of times you can find them in very shallow places though they can live deep as well um they tend to be Cecil but what&#39;s crazy is they can actually move their base around and find new places to go in many cases if they want to so corals are really one of like near and dear to my heart lots of people have a soft spot for corals they just love them and we&#39;re going to spend a few minutes just talking about them here so they are actually a type of polyp that excretes a skeleton so if you look at these guys here in this close-up they look a lot like a jellyfish Medusa and they just closed up in this GIF but they&#39;ll open right back up they look like a jellyfish and they are a distant cousin of jellyfish and um for their life history they were almost like jellyfish that like decided hey we don&#39;t want to be just planktonic floating around we want to stop and build a hard calcium carbonate skeleton and move all of our relatives around us so it&#39;s you when you think about a coral you can think about a bunch of like tiny little upside down jellyfish that have like glued themselves there with calcium carbonate all over so it really is a lot of people look at corals and they&#39;re like that&#39;s just a rock it&#39;s not it&#39;s a many many many um it&#39;s a whole colony of small organisms living together and if you rub up on Coral and stuff and get injured by it a lot of times it can be more painful than just getting scratched by a rock because it does have a stinging property in many cases just like a jellyfish so these guys by making these Rocky um Rocky skeletons for themselves they end up actually being a reef building type of creature that helps other organisms have a space to live so one type of coral that people don&#39;t even know exists in many cases are the soft corals So Soft corals um do have colonies um sort of like plants and I put two that I really like seeing in Southern California one is called the sea pen that when you um go diving here in Southern California you can often see these this is you know some people think southern California doesn&#39;t have Coral but we do and here&#39;s one of our soft corals and then this is another Coral called the sea panzan when you see it on the ocean floor it looks like this it doesn&#39;t look like much they&#39;re not very big um here&#39;s someone holding one of them here but what&#39;s so cool is because they are a coral um they have a they some like jellyfish relatives have bioluminescent properties and this is called a sea pansy that actually does have the bioluminescent properties this is a video by golf specimen Aquarium sea pansy glow and I highly recommend you check it out what it shows is at night when you go back if you are lucky to find one of these wherever you touch it it will light up and glow in that space like wherever it is touched um you activate it and you don&#39;t want to do it too much because then it&#39;s a living creature but that&#39;s what it is capable of doing and it&#39;s really really cool so um for Nutri nutrition and digestion they do have a gastrovascular tissue and cavity kind of gross their um the same part for taking in food is used for Waste as well so it&#39;s like having your food come in your mouth and out of your mouth at the end which is a little bit gross they um lots of them are suspension feeders but of course you know like jellyfish and box jellies that we just went over are carnivorous sea anemones will generally feed on invertebrates and just floating things in the water but Stony corals get the majority of their food from a symbiotic relationship that they have with zozantheli and just because this is so so important to what is going on in our coral reefs I need to press pause here for a minute and just take a minute to talk to you about this very very important relationship that not that many people know the details of so corals if I&#39;m zooming in on it you know it looks like a polyp we just talked about that and here&#39;s like a really close-in picture of what a couple of coral polyps look like and if you look at them really closely you&#39;ll see that at least the outside Fringe of these ones are kind of like clear white translucent-ish right they don&#39;t have very much color and um corals don&#39;t have much natural color or any at all they just are clear white translucent-ish and also Coral over time has lost its evolutionary ability to make enough food for itself so like many many many organisms it takes on um other organisms in a mutualistic relationship where they both can benefit so Coral basically says hey I have a hard um cavity that&#39;s empty I&#39;ll take on a renter that can pay me in food so it actually takes this organism called zozantheli and zosantheli um is actually very brightly colorful and whatever color moves into the coral that ends up being the color of the coral so some Coral have a relationship with like a pink zosanthelier orange zosantheli or bright bright pink or purple or whatever color that it is that now when they take in that zozanthelian concentrate it that will appear to be the color of the coral is actually the zozantheli that lives inside of it so so Sam feli has the word um zoo in the beginning and zoo or Zoo means um animal so it&#39;s a plankton that um digests like an animal but it actually photosynthesizes like a plant so it goes and lives inside of the coral and it uses the sunlight to turn that sunlight into food and it gets plenty of food for itself and it&#39;s actually capable of passing a lot of the food for the coral like I said earlier Coral can&#39;t feed itself in fact it&#39;s such a bad and dire situation the coral can only make about 25 of its own food depending on the species so it relies on this zosantheli for about 75 percent of its food so it&#39;s kind of a lot and it&#39;s really important that the zozanthal you&#39;re there well also we talked about it&#39;s like an animal so it digests even though it&#39;s photosynthesizing it&#39;s digesting food like an animal and creating waste and like we talked about that waste has to go out through the top of the coral and the coral doesn&#39;t have a good method for getting rid of it but it roughly can get rid of enough with the currents washing through to make it okay except the oceans have gotten a lot warmer um the ozone is like thinner all over and the light coming in is more intense and the water is warmer on these zozantheli so it&#39;s causing a lot of these zosantheli to actually over photosynthesize and over respirate and make too much waste so they&#39;re generating so much waste that the coral starts to get septic and um the coral is just like you&#39;re a bad renter you used to pay me but now you just have waste and garbage and sewage everywhere you need to leave and so the coral actually expels the zozanthelli and kicks it out and it kicks out the zozan felly and then the coral is there stuck with this sludgy waist and it can actually be bright yellow at first when this happens from this septic like waste that&#39;s inside um eventually that&#39;ll get washed out by currents but now think about it the coral does not have enough food to feed itself plus it&#39;s just been a wash with all of this septic septic um waste and so the coral is very sick but Additionally the coral has also lost its color because remember it was the zosantheli that gave the coral its color so now the coral is back to this white translucent color and so it&#39;s said to be bleached and so when you see a coral that it&#39;s bleached it&#39;s very very very stressed because it doesn&#39;t have the right amount of food and within about two weeks to a month on only 25 food it will die and then also remember that during this time there&#39;s a lot of other organisms like tons of other organisms like algae or like we talked about earlier sponges whatever that will all want to move in and take the space of that Coral so it&#39;s not only stressed and has sepsis and it&#39;s not getting the right amount of food but all these other organisms that have wanted to compete like for space now see it as an easy target to come in and Target it so a bleached Coral can come back and can get restored if conditions get better but um it is tough it&#39;s tough to do that because you&#39;ve got about a two-week window before the coral is so far gone that it dies and when it dies it will actually very rapidly you would think the skeleton would just hold and be there in bright and beautiful and white even though it&#39;s dead it would still be pretty but it doesn&#39;t it turns into Coral Rubble like really rapidly I actually have a video here um that you can check out where I&#39;m doing a swim up in Hawaii of a space that this um space has some good living Coral but it also has some very dead coral and you can see it in the video if you check it out later um some of it is totally alive but others spots you can see algae and things growing on it this is a very stressed Coral wall and what I heard was that there was a really really bad storm that had hit it about a year earlier um and so it&#39;s in rough shape and at the end you can see I just pick up some of the coral Rubble where it&#39;s just totally dead and it&#39;s it&#39;s a huge bummer um this is a video by Colette Ben Sultan living ocean foundations Coral what do they eat that explains the process that I just did um but a little differently and with good images and then here&#39;s a video by Deep Marine scenes facts corals and coral reefs if you have to pick an order I would say watch this one first and then watch the Khaled Ben Sultan second so I think this is the part where I go up and just kind of show you that this is all Rubble that&#39;s all just totally dead coral going all the way up that wall and what it looks like to have that it&#39;s just really sad and something you generally just hate to see so hydrazone&#39;s um reproduce because now we&#39;re going to talk about reproduction of these organisms they have a polyp colony and the polyps are actually their asexual stage and they will break off the tops of these and that will be the Medusa the Medusa can have sperm or egg and then that will get fertilized um with each other that&#39;s their sexual stage and that um fertilized Aid will turn into a planular larva which will swim around until it finds a place to settle and make a polyp the scyphozoans this is like a moon jelly is pretty um characteristic of the whole group and so this is a good drawing of what moon jelly replication looks like they also have the polyps stage but interesting they make this like Tower of medusas and then they will just break off a chunk of medusas or maybe just one but sometimes they&#39;ll release like three or four all at once and then the medusas will float around male female until they fertilize an egg and make the planuler larvae same thing till it settles here&#39;s a video by ocean wise ever wondered how baby jellyfish enter the world that shows this planular larvae it&#39;s only like a minute long um it shows this Tower of Medusa&#39;s breaking off and it&#39;s just interesting so anthaz Owens remember anthazoins are the flower-like ones so that&#39;s anemones or corals um they have asexual reproduction where a part breaks off but the bottom disc is still attached so um in another video I show like an anchor that a cruise ship dropped on um coral and the anchor is dragging it along and those corals when you find broken up corals when you&#39;re scuba diving you can help save them by just doing what you see here you don&#39;t need a cage just as long as they have that bottom disc on them you can put it upright in an upright position and that bottom disc can um affix to a new substrate hopefully the substrate is like hard not Sandy and they can start to reattach themselves you can also have um a fission where peace breaks off like it fragments or you can have budding where it does grow a little mini me and then and then it sloughs off and makes a new clone um you can also have sexual reproduction uh where male and female sperm and eggs are released in the water column until they fertilize and then it&#39;ll form a planular larva which will swim around and make a new Little Colony okay so um the ecological relationship of cnidarians and the role that they play here&#39;s a video that shows you what I want to talk to you about next the video by National Geographic see a sea turtle devour a jellyfish like spaghetti um going along with the theme that sea turtles have digestive systems of Steel they are crazy predators of jellyfish so this is I think a green sea turtle here um eating a jellyfish and they will just rip it apart this is just a one or two minute video that I recommend checking out uh because it shows it better than it shows in this GIF but in this gift you can kind of see it the sea turtle will actually come up to the jellyfish and because they&#39;re only vulnerable part is their eyes often they will close their eyes and then they will use their friend um leg to kind of push away or paddle away the jellyfish in One Direction while their mouth rips it off in the other direction and they just tear them apart like spaghetti so it becomes an important food source that way um other ecological relationships of cnidarians is like our corals make very important habitats for other organisms it&#39;s very difficult to see in this picture but I had a lot to put on this slide um this is a sea turtle sleeping under a coral and this is a shark swimming under like little reef shark swimming sleeping under the coral there&#39;s a large number of organisms that not only use this as their home these fish have specific shapes to Dart in and out of the coral for safety and to use it as their home so many organisms rely on corals um it&#39;s estimated that Coral only makes up a tiny fraction of the world&#39;s oceans but when scientists have tried to estimate how many organisms at one point or another rely on Coral either for food or for safety or to raise their young and be a nursery for their young it&#39;s something like 25 of the organisms in the ocean rely on Coral at some point in their life history and here you can and see that there are certain fish that are even adapted with very tight little mouth Parts because they just swim around all day pecking at the coral eating the tiny little living polyps so they rely on eating polyps all day and that type of organism is called a corellivore and just like a carnivore eats meat or an herbivore eats plants Corella Flores specialize in eating Coral specifically so a large number of organisms rely on them then there&#39;s also a lot of symbiotic relationships remember symbiotic relationships just mean that there is a relationship it doesn&#39;t mean if it&#39;s good or bad um here&#39;s an interesting relationship with Portuguese man of war and the Portuguese man of war fish so the Portuguese man of war fish is a very intense little fish that happens to be 10 times more resistant to portuguese man of war toxins than other fish and it just swims along with the Portuguese man of war eating its gonads like its sex organs and eating its tentacles as it moves along um and unlike anemones or like clownfish around an enemies clownfish will secrete a mucus on themselves so they&#39;re not as bothered by the stinging cells this fish does not have that this fish instead has lots of extra vertebrates vertebrae that make it super agile and it will actually just constantly be darting away and avoiding the um stings of the Portuguese man of war but if it does get stung it actually has its own anti-venom too so it just swims along here eating its gonads and tentacles as it moves along um so interesting relationship another one is that um in sponges specifically or hermit crabs hermit crabs with anemones some of them will actually put anemones on their shell and the Anemones will get free food from the crab that after it nibbles on things and the anatomies give the crab protection so that would be a good mutualistic relationship this is a video that shows that by Blue World TV incredible footage of a hermit crab this hermit crab is actually changing its shell and when it changes and goes to a larger shell it picks off the Anemones and puts it on the new shell to take it with it totally crazy this is a video by coral reef 101 from National Geographic that you can look up as well and then here are just a few really good videos also from Professor Dave explains nidophoric home jellies also Professor Dave phylum Nigeria part 6 on coral reefs and a video by National Geographic world&#39;s deadliest comb jellies that&#39;s really interesting so now moving away from jellies and their stinging cells are the comb jellies these guys look like jellyfish and they would scare you like crazy with their bioluminescence but they actually lack stinging cells all together they are planktonic just floating around they&#39;re nearly transparent they have a status bubble inside of them that helps Orient them like up down and helps them figure out how to move or where to go they&#39;re for digestion and nutrition they tend to eat plankton larva fish fish eggs they have something called a collar blast which is a sticky adhesive cell that they use to capture their prey and here&#39;s a video by Alvaro megado swallowed holocome jelly praying on another comb jelly so you can actually see the calm jelly eat another one and then slowly how it&#39;s digested into little bits because it&#39;s transparent so you can see right through it for reproduction they are mostly hermaphroditic where they have male and female parts and those eventually will find each other and grow into a full adult here&#39;s a deep Marine Seas scenes facts that comb jelly tenofora where it talks about that a little bit more okay so with bilateral symmetry since we talked about um body plans and how we we covered La radial symmetry this is called bilateral symmetry so bilateral symmetry you can&#39;t just cut it in every direction and have equal parts there&#39;s one distinct way that this can be cut into two and usually organisms that have this tend to have um a concentrated a concentrated region that you would end up calling the head of the organism so the first um bilaterally symmetrical animal we&#39;re going to talk about is the flatworms and there&#39;s the turbularians and the flukes and the tapeworms and we&#39;ll go into a little bit more detail with them here here&#39;s a video from Deep Marine scenes facts Marine flat worms and you can see what they look like and how they move they&#39;re mostly on the bottom um dwellers and they live in the tiny spaces in between sand usually as a way to eat they have sensory receptors to detect light or chemicals or movements or maintain balance there&#39;s also some that live in the in side of other organisms so for reproduction this is really really crazy they actually reproduce asexually and their hermaphroditic when they have sexual reproduction okay this is the crazy part both of them have a penis and a vagina for mating with each other at the same time crazy their penis is like a sword and it has two prongs to it so here&#39;s two in this GIF and the gift does not do this mating process justice but these are two um flatworms that have found each other and they are going to fight each other and try to stab each other with their two-pronged penis when one of them stabs the other one with their two pronged penis you just lost and now you got impregnated and then that the other one will go away the winner goes away the loser now gets pregnant with all of the eggs and has to use their body um strength and energy to go towards growing and and caring for those those eggs while it&#39;s in its body so the organisms don&#39;t want to lose this battle they don&#39;t want to be the one that got stabbed so um while turbulyrians produce just a few eggs there are parasitic flatworms that produce 10 to 100 000 times more eggs then um the turbularians and obviously it it&#39;s parasitic that&#39;s kind of disgusting and it just goes out there and it&#39;s hoping to make it in its way inside of another organism so it can grow in it okay if you are interested in the um mating of flatworms here&#39;s a video by BBC Earth meet the penis fencing flatworm that goes into video detail of what this fencing fight joust looks like and it&#39;s really intense um okay so in ecology what is the role of flatworms well um they basically can cycle nutrients around and change help it to change forms the it eats other things other things eat it there&#39;s also in on a gross side they are parasitic some of them can be parasitic and so because they&#39;re a parasite and they&#39;re living in a host like um flatworms will have or I&#39;m sorry um sperm whales for instance can have a tapeworm that is 30 meters long 30 meters long inside of them and that obviously makes the whale a lot less fit and it could get it could die because of that but then its body could be eaten by other things and so it&#39;s cycling nutrients still not my favorite way to go okay so um there are also ribbon worms ribbon worms are benthic they have external fertilization they are carnivores that have this crazy proboscis a proboscis is almost like a tongue that goes out and grabs food and here&#39;s a gif of what that looks like but the next gif is even better this looks like it would be fake right here but it&#39;s totally not this is a ribbon worm throwing out its proboscis which is effectively used like a web to capture prey it&#39;s a thing of my nightmares um so they can be important in the ecosystem because they make Burrows they cycle nutrients they&#39;re abandoned Burrows can serve as habitat and things like that okay so we&#39;re gonna switch to lofophoreaids which not that much is known on these and we&#39;re gonna go through them pretty rapidly the first one that I want to talk about is the um foreignids foreignids have a tube that they live in that they secrete of protein or chitin um they actually catch Plankton and dead and decaying matter that is floating nearby them here is one form that we see in Southern California called the California horseshoe worm and you can see why it&#39;s called the Horseshoe worm um they can produce sexually or asexually and they have a planktonic stage this is kind of what it can look like um this is a video by Alvaro megado the Horseshoe worm um for Anita that you can check out and then we&#39;re going to talk about bryz Owens so these earlier in this video I said they compete with sponges for space and that&#39;s because they live on colonies rocks shells algae Mangrove um they can sometimes they&#39;re they are very very abundant and found all over the place which it makes them important in the in the food chain because lots of other organisms will eat them they&#39;re also planktonic and most are hermaphrodites um the brachial pods um our benthic they live on the bottom these guys have two different shells so the top shell is a different shape than the bottom shell so if you think of like mollusks or bivalves um you might think oh that&#39;s just like like a mollusk or a bivalve like a clam but it&#39;s not because they have different shaped two different shaped cells they also have a flesh fleshy stock that they put into the sand to help them be upright they eat dead into cane matter in different algaes different they have different Sexes with a larva and a planktonic stage and their Plankton will eventually settle after like a day and be a grown-up this is a video um by the paleontology Association brachiopods small But Mighty that kind of goes into more detail on them so as a group these guys um lofophorates as a whole are filter your feeders and I like I said they do feed a lot of organisms they are somewhat disliked by ships a lot of times because they&#39;ll grow on whatever they can find and because they&#39;re so abundant they tend to grow on the bottoms of ships making them kind of slimy and they&#39;re part of what is called the felling Community where they are not appreciated um by the boating community so that is our chapter on Lower invertebrates I hope you grew an appreciation from them it&#39;s everything from sponges to corals and they&#39;re such an important important part of our marine ecosystem

Transcript for:Chapter 8: Lower Invertebrates

Transcript for:
Chapter 8: Lower Invertebrates