Chordates Animals With Some Real Spine

alright biology 11 our last lecture in the diversity unit is chordates also known as some animals with some real spine not really afraid of these animals alright these are the ones that you think when you think of an animal it's probably chordate you only want to have problem with lamas don't like them think they're very distrustful animal the terrible hair bad teeth they spit at you the crazy look in their eyes like they they don't care like they'll do what they want and just can't be around an animal like that anyway if you're llama farmer apologize and yeah no you know what no sorry not sorry anyway on with the show so what does chordate chordate is an animal that has nerve cord that runs along their back it's called the dorsal nerve cord so dorsal nerve cord dorsal means along the back like the dorsal fin of shark is like in those jaws movies it's that fin that pokes above the water well that's the fin that comes in that you know the Sharks back so dorsal nerve cord means your nerve cord runs along your back ours does this we're chordate all right so all chordates have gill slits near their throats at some point in their lives or their development now for us it's during our prenatal development for things like fish and well the Sharks just mentioned they have them as adults all right so we don't have gills that's not what I'm saying our gills they dissolve during our development they go away but we do have them early on an embryonic development so while we're in our mothers wombs and all of us have tail at some point yes just like the gills I'm not saying we have tail we do have tail bone that at one point was more elongated and then it fused together to form the coccyx that our tailbone but lots of chordates do have tails ours goes away during prenatal development again and all chordates show bilateral symmetry if you remember bilateral symmetry that's where you could take an organism and cut it straight down the middle and have two equal halves alright so that was bilateral symmetry everybody in this group has that all right now something we have to differentiate between there's chordates and there's vertebrates and all vertebrates are chordates but not all chordates are vertebrates all right seems kind of weird so core date is the larger group this just means you have the dorsal nerve cord I'll just put dorsal nc dorsal nerve cord now vertebrate has the vertebral column it has the bones right protecting its nerve cord right so this is like saying insects and beetles alright insects is the larger group there's whole bunch of different insects beetles is one group within it same thing here chordates is the larger group vertebrates is still pretty big group but it doesn't account for all of these right the same way I'd say all beetles are insects you can say all vertebrates are chordates but you can't say all insects are beetles so you can't say all of these are these because there are some chordates that don't have cartilage or bony skeleton protecting their nerve cord so we've got the vertebral column our spinal column it's all those bones that extend down from the back of our skull down to our tail bone all right so many many chordates have that but not all of them alright there's two early classes of chordates called the Euro core data and cephalo core data alright these are very small creatures they don't have the bones or cartilage skeleton protecting their dorsal nerve cord they still have it running down their back their dorsal side but they don't have any real protection for it the Euro core data are tune our tunicates these are small marine creatures marine meaning in the ocean and then we have the cephalic core data which are the LAN slits these are also small marine creatures so you probably haven't seen these things around don't think they're widely exposed whole lot but if you do go into and was doing marine ecology we got these things all the time they're not an uncommon thing in the ocean but again they're it's just too small little factions within this larger group and because of the Euro core data and cephalo core data we can't say that all of these are the same so and again neither one of them had their bony vertebral column or even one made out of cartilage to protect their dorsal nerve cord alright so what is vertebrate vertebrate has backbone it has those vertebrae that protect their dorsal nerve cord all right so other things that we're gonna see in the vertebrates scull to protect their highly developed in large brains well-developed internal cavities and organs if we man if we can get back into the school at some point and get through this pandemic and get back into the doors of st. Mary you know we do that section in grade 11 the pig dissection and you see the internal cavities and just how neatly the organs are placed in there and that's you know well-developed internal cavities that house the organs I'd love to say we're gonna get back in there I'm not sure at this point but we'll see survivals little more important they have ventral heart so ventral heart means that there has chambers and they have these highly muscled eyes diva muscle eyes the word anyway they very muscular bottom sections of the heart called the ventricles fossilised good one anyway gas exchanges either done through gills if you're an aquatic species or lungs if your terrestrial aquatic water terrestrial land and we're going to go through whole bunch of different groups within the vertebrates and we've labeled them here we'll go through them so Agnetha is our first class so phylum Chordata and then our first class if you remember our levels of classification kingdom phylum class order family genus species so these are all classes class Agnetha these are the jawless fish there's not whole lot of these but there are some species still alive today so we'll go over them quickly like Nathan's or jawless fish there's two main groups the hagfish and the lampreys there's not very many species alive today there's very few of them that are still around today they get out competed for by the by the fish that have jaws so let praise our ectoparasites that means they're parasites they live off the resources of another living thing and ecto means they they live on the outside like leech leech draws your blood but it still lives on the outside of your body that's what these lampreys do and the hagfish is scavenger we know scavengers wait for someone else to kill something any you know bones and meat that's left on the carcass they'll go over and they'll they'll eat from that so there's lamprey there you can see there's its mouth there's no jaw there's no hinge there so it just stays open like that 24/7 so there's one there the ruler next to it just so you can see like these are not small little things you'd notice that if that was swimming by you here's game warden and it's showing some fish that had an issue with my appraising lampreys you can see that the huge wounds on the side of the fish where the lamprey was stuck to it here's hagfish again scavenger so it kind of just lurks around and hides off in the corners and crevices in that and then something like shark or barracuda happens to take something down there'd be little bits of food that would float away from that carcass that this thing could feed on and there's what its mouth looks like and it doesn't again it doesn't close it doesn't have that hinge that we have or that other vertebrates have and there's some guy that's just put lamprey on his head don't know why you do that but guess it made for good photo anyway chondrichthyes is our next class chondrichthyes are your cartilaginous fish now this it fees right here when you see that that means fish alright we're gonna see this in another class within the chordates but we're also where you also may have seen this is an ichthyosaur an ichthyosaur was one of the few aquatic dinosaurs it's swam along it had fins not lakes so it deus or really meant pay to fish dinosaur really the Kandra apart here means cartilaginous chondrocytes in your body are what make cartilage so chondrocyte is basically cartilage making cell site is cell so chondrocytes is where you may have seen that before and that just basically means cartilage so cartilage if you want to feel cartilage just feel the end of your nose your earlobes alright so the end of your nose that's cartilage your earlobes are cartilage that's what their skeleton is made out of so sharks and skates and rays which belong to this group they have softer sort of skeleton shark skates and rays so when things develop and they start to grow skeleton including ourselves and dogs and and birds and you know reptiles the skeleton starts off as cartilage and then it undergoes process of ossification ossification is where the bone cells take over and you get that hard you know like rock like bones like what we have our bones are hard right saying with your dog saying with the lizard saying with frog same with bird but these things that cartilage skeleton develops and it never undergoes that process of ossification alright so that's the difference so there's still skeleton there there's still you know vertebral column protecting that dorsal nerve cord it's just made out of softer material they have two sets of paired fins pectoral fins pectoral means coming out of the chest area you think of your pecs if you go to the gym and work out your pecs it's chess day and pelvic fins your pelvis is where your legs meet up with the rest of your body so that's down lower and have some pictures that will show that and breathing is done as water moves over gills they can't ever stop so sharks can't stop swimming rays can't stop swimming they have to at least be moving at some point and when sharks guess you know put air quotes around it when they sleep they go into trance-like state but they still have to continue moving because if water stops going over their gills they stop getting the infusion of oxygen into their blood and that will mean death because you need oxygen to make energy sharks are ovoviviparous so here's word I'll see if can get it in here ovoviviparous ovo's egg and vivvy is life all right so eggs are fertilized internally inside of the female so she has eggs they get fertilized and inside of her the eggs will hatch so it looks like she's giving birth to live young same way human would or your cat would or whatever right but the eggs that are in there do have shell it's soft shell and usually quite usually what happens is the first shark or two that hatches eats their siblings so you want to be the first one out of the egg if you're in clutch of eggs that's that's inside of mother shark you want to be the first one out that's what how they gain their first nutrition and then they are giving birth to so it looks like they're given birth to live young but they started eggs at first so we look at some here here is great white shark here you can see the dorsal fin here here are your pectoral fins those larger ones on the side the pelvic fins you can kind of see in this one down here and of course you have your tail here if something gray and streamlined like this is swimming out in the ocean the way to tell us apart from you know shark that's gonna eat you in the dolphin that's gonna help you out is the tail you can see the tail they both have the dorsal fin but the tail on dolphin the tail goes side to side it goes east to west on shark it goes north to south the tail fin there's another great white and you can see very brave guy much braver than in that cage here's one here you can see again there's our pectoral fins and the pelvic fins are down here you can actually enlarge that picture in your own slideshow there's another one here you can see this shark has breached the water going after prey and you can see here pelvic fins and pectoral fins here you can see the gills here as well here is array again these very large extensions off to the side are the pectoral fins and you can see the two smaller ones down here where the tail meets the body those are the pelvic fins and there you can see it there again all right and again there so the next one is class Ostia keys so if look at that word again can see the ick these at the end of it so us yech these no big these we know is fish and osteo is bone so these are bony fish an osteocyte is what makes it's bone cell it's what makes up your skeleton inside of your body so osteo means bone egg these is fish so these are the bony fish these are like your tuna and your bass and sturgeon and all those other things lot of the fish you go out and catch so the internal skeleton starts as cartilage but it gets replaced with bone it undergoes ossification they have flat smooth lightweight scales that cover over their body the sharks kind of have like toughen skin they don't have the scales like these fish do they use gills to breathe but what they have that the sharks don't have is thing called an operculum and the operculum so whatever does fish face and they take their hands and they put them by their ears and they do this sort of thing when they're the fish and they're going like this all right someone does the fish face like that they've got their hands doing that at the size of their head what that is that's the operculum it's little plate that goes over their gills and it moves back and forth and what it does is it fans or pumps water over the gills so they don't have to continuously move so if this thing has to you know hide from from larger predator like shark it can go into little nook or crevice and it can stay there it can stop swimming and just remain motionless and wait for the danger to pass shark could never do that so this little perk ulam helps these things breathe even when they're not moving most bony fish also have swim bladders and the swim bladder is something that they can fill up full of water and it helps them remain buoyant at different levels within the water right it's kind of like weight belt that scuba diver may have it helps them maintain their position within the water without it they might float to the surface all right the lungfish actually uses its swim bladder as modified lung it fills it full of air but it's the only one that can do that most fish use it for swimming purposes and what they do is and I'm sorry but I've got to do it it's my scientific duty I'm gonna destroy some Disney movies as we go through this course Finding Nemo right if you remember Finding Nemo the clownfish she got the little clownfish their Nemo and his dad and his dad zico Nemo care for you so much let's go find can't even remember what they were gonna go find but anyway the dad really care are they were Finding Nemo they had to find him well where's my head at the whole movie was called Finding Nemo that makes sense alright so Nemo gets lost and the dads like we got to go find them we got to go find my son that's lie that's Disney lie they do not care fish do not care about their children alright so Disney lied to you they're sorry if your hearts broken there's not much can do about that but what happens is the females deposit their eggs on the floor of the well on the ocean floor the lake bed right depending if they're freshwater or marine and then the male's come along and just spray their sperm in the general area so they can sense that there's the same species as me has laid some eggs here they go and they spray their sperm there there's no fish sex or nothing like that female lays eggs swims away male sprays the sperm swims away little fish never know who their parents are know that's much sadder movie and that's why Disney lied to you and said look the fish parents care but that's the way it is alright fish hatchlings never know their real parents Finding Nemo is lie anyway I'll see piece so here's tuna now this picture doesn't show you how big tuna can get but I've seen tuna caught down in Nova Scotia and these things can be several hundred pounds I've seen one bluefin tuna fill up the back bed of pickup truck you know 800 900 pounds some of these things and what they do is when they take the tuna to the shore so you catch it you take the tune of the shore they take little core out of the tuna and there's guy there on the shore right outside of the fish plant and he tells you the grade of the meat and then they weigh the fish and you get paid by that grade so if you have really good grade fish and I'm gonna make the prices up cuz don't know them I've only seen it kind of go on don't know what the going rate of tuna meat is but let's say you have great fish the quality of the meat is awesome you might get five bucks pound if your fish is little less awesome you might get three dollars and fifty cents pound so that's kind of what they do here but I've seen guys come in off the boats growing up in Cape writing that they've they come in with fish that are like 800 900 pounds I've seen couple that probably are topping thousand and these things just fill up the back bed of truck they're monstrous they have crane right on the dock to get those ones off the boats there is barracuda it's marine predator has very sharp teeth also the topic of wicked song from heart google it put it on Spotify you'll see sculpins sculpins these are fish that when we fish off docks and that back in Cape Breton we try to get good fish that you could eat and every so often you'd hook one of these bad boys and they're just useless they can't do anything so you know would always try to throw them back in but we'd always say some cool movie line and then whip them back into the water we weren't very nice guess but sculpins thought I'd throw those in here childhood memory and there's swordfish we have these off of the grand banks of Newfoundland people go out there and they catch Marlin or soar sorry think probably swordfish not Marlin they're related think but that's that our next class is amphibia the amphibians so the amphibians are an important step in our evolution because what they do is they represent the bridge of all life being aquatic to good deal of life becoming terrestrial so this is how we biologists believe that this is how we made the move from becoming land-based species or having land-based life-forms from well what used to be all aquatic life forms so they do still need water if you're an unfitting you still need water in fact part of your life cycle if you think of frog that's an afib Ian's part of its life cycle the tadpole swims in the water it lives in the water exclusively it has gills all right and then it goes through metamorphosis and becomes frog and can then be terrestrial live on the land so they start with gills they developed lungs later on the Frog is three chambered heart air how do they breathe well they do have lungs so they can breathe like we do and get oxygen into its body and make energy from it but they can also breathe through their skin some of these species their skin is very very thin and diffusion can take place right across the surface of the skin so it'll be like you closing off your nose and mouth and you you wouldn't die you could breathe through your skin amphibians reproduce very similarly to fish the mother lays the eggs or the eggs will come out of the female of the species the male sprays sperm there is no active sex or like that and then they bugger off and little frog legs never know who their frog parents are so another example of very poor parenting but use you what nature does to combat this if you're if you're not very good parent you get tons and tons and tons of offspring and mother nature goes well some of them will get through if you only have few offspring like humans or bears or other animals elephants and that you often invest lot of your energy as parent there's lot more energy into parenting all right common amphibians include frogs toads salamanders and all right so if we look here there's poison dart frog so when we see something like this in nature and we've mentioned it before in the invertebrates look at the bright colors on that frog the frog get of its back has cells that exude neurotoxin and in fact indigenous hunters what they'll do is they'll take the tips of their arrows and they'll rub them on the back of the Frog and then when they go hunting when the arrow pierces whatever there is that they're hunting that neurotoxin breaks down the brains control of the muscles and the thing basically stops moving and then they can eat it there is leopard frog these are the types of frogs you've probably dissected in grade 10 and there is salamander there we have sent lots of salamanders around if you go hunting and looking around for them you'll find them and there's toad toad has little bit rougher surface of this to the skin there used to say if you handle toads you got warts because they look like if they have covered in warts that's that's not true you can hang out with toads you won't get warts and here's tadpole that's right in the middle of metamorphosis so you can still see the tail section here but you can see the legs developing and then there's few more poison dart frogs our next class are the reptiles feel like don't have to write down what they are because feel you probably know what these things they're like said when we think of animals this is what we think of right things like frogs things like sharks and fish and and reptiles so reptiles alligators crocodiles turtles lizards snakes all of those things they're all reptiles reptiles kind of picked up where amphibians left off in terms of coming out of the water and onto the land they have terrestrial lifestyle only theirs can be some reptiles are exclusively terrestrial they don't they don't breathe in the water they don't need the water to - you know - how is their young or anything like that so they've really become specific to terrestrial lifestyle they don't need water to reproduce they can live fine just on land they don't have like tadpole stage they have eggs that have hard shell amphibians have soft shell egg these have hard shell and so it minimizes water loss around the young fertilization is internal so that means there is sex act here they have to actually inseminate the female and then eggs fertilized eggs are laid and then they're looked after by by the parents tough scaly skin restricts water loss they don't have that thin skin that allows for diffusion like their fins do they have tough scaly skin and they have kidneys that can form really highly concentrated urine so your kidneys look after your water balance so if it's you haven't had whole lot of water for nymph in that could be deadly but for reptile their kidneys just concentrate their urine and allow more water to be kept in the body and the lungs of reptile are considerably larger - in fitting because again you don't have the help of oxygen diffusing through the skin their skin is too thick and too tough so if we look at some reptiles here don't know what this man is doing but it's wrong you just look at him there you know who wants to go pet the 15-foot crocodile this guy raised his hand don't know if he's still alive would doubt it mean he's play danger here anyway braver than me there's another picture you can see that the tough scaly surface of the of the crocodile there tortoise here's snake now this is one of these snakes one of them is safe and one of them is dangerous and think of its red next to yellow deadly fellow red next to black friend of Jack so if you look at the band's the red here is next to the yellow so this is the deadly fellow this is the one that if it bites you you're probably gonna die there's another snake that mimics this one because no one wants to go near the snake again notice the bright colors but the red is next to the black and not the yellow so right next to black friend of Jack red next to yellow deadly fellow so this is the deadly one there's sea snake sea snake some sea snakes some sea snake species tongue twister have some of the deadliest toxins on the planet of all the animals sea snakes have some really deadly toxins our next group is Abbey's and Abbey's are the birds right because they are aviators they fly that's where Abbie's comes from it means flight all right so we look here the avians are the birds right they have they developed from reptiles we all learn that in Jurassic Park or maybe your parents did remember the original Jurassic Park that was the big speech at the beginning birds came from reptiles anyway they have scales on their legs reptiles had scales they have large yoked eggs in firm shell reptiles have that there's no metamorphosis in the young the metamorphosis is like the tadpole which kind of look like sperm cell becoming frog reptiles don't have that well neither do birds so that means when reptile or bird hatches out of its egg it's little version of itself of the adult so out of an egg for fish you get tadpole or sorry totally wrong out of an egg for an amphibian you get tadpole that doesn't look like we know it will become frog but it has to go through metamorphosis first birds and reptiles when their egg hatched so if you have crocodile what happed is that the egg is little crocodile it looks like it when you have bird chicken what hatches is chick it looks like little chicken so there's no metamorphosis in the young birds differ though from these previous groups from the reptiles because they are endotherms endotherms endo means inside or inner and therm is heat which means they have an internal body temperature that they maintain ours is 37 degrees Celsius so our body works and expends energy to maintain that 37 degrees Celsius because that's what our cells work optimally in is that temperature of 37 degrees that's hotter than it is outside more often than not so we do have to put energy towards that birds are the same way they have to maintain the internal body temperature and keep it there all the other things so far the fish and the reptiles amphibians they're ectotherms ectotherms are cold-blooded they're not warm-blooded like the birds and us are they're cold-blooded and basically how they warm up is they have to go out and lay out in the sunlight or go lay somewhere where it's warm right to warm up their bodies and get their metabolism going we don't have to worry about that neither do the birds they're endothermic so are we they also have feathers which evolved from scales and of course the feathers are one of the things that allow them to preserve heat because there's layers of feathers just like layers of clothes will help you preserve heat and they allow for flight hollow bones the bones are still hard they still undergo ossification so they're still made of osteocytes their heart but they're hollow this lightens the bird up so it can fly and then of course they have air sacs that branch off of their throat area all right the trachea the wind too and what this does it helps them with buoyancy water is fluid but so is air right air is fluid as well so to keep them buoyant and balanced within the air they have air sacs that they can that they can partially inflate and that helps the bird with its buoyancy within the air if you look at some of IANS here this is bald eagle we have these in Cape Breton they're big big birds there was bald eagle nest up behind my place and bet you the nest was probably at least two-and-a-half to three meters in diameter that's through the middle of the nest it was huge nest the birds are very very big there's an ostrich there with baby ostriches there's penguin hummingbird hummingbirds need to eat ton of calories day because the metabolism is just so highly ramped up and Senor Tucan remember my kids used to watch Dora the Explorer in this guy didn't trust him he was the only character didn't have like the soft childlike voice it was like everyone else spoke like baby almost and then this guy would come along with his dark deep accent and just didn't trust him thought he was always going to lead Dora astray anyway the mammals last Mammalia this is us so class Mammalia has mammary glands and mammary glands are what produce milk to feed the young alright so the females do that for us well the females do pretty much everyone here other traits of mammals they're endothermic again just like the birds we just discussed that they maintain an inner temperature that's higher than the environment more often not they're covered in hair fur and we have four chambered heart so we look here there's lion very large mammal here's kangaroo now there's different types of mammals lion is placental mammal just like we are there's placenta inside with the children as they're developing inside of the mother but the Sena helps nourish them and do all that sort of stuff here the kangaroo it gives it gives birth to premature young so when the lion cubs are born they live outside of the parents body and they're good to go mean they got to be looked after and taught but they're big they don't have to be protected as much they can you know walk around after little bit and there they live outside the parents body the Kangaroos and that these are marsupial mammals and what they do is they give birth to the young while they're still really premature so when the young kangaroo comes into the mother's body it's not ready to live outside of the mother's body yet so it goes into pouch and the mammary glands are in that pouch and the rest of the development before it can live freely outside the parent occurs inside of that pouch and that's common trait to all the marsupials and there's duck-billed platypus this is our third main category of mammals these are monotreme mammals this is one of the few types of mammals that lay egg right no eggs here no eggs here these things lay eggs and mean eggs with shell right there's silver back at the zoo large gorilla there's cat in dog there's nice friendly opossum actually possums can be quite friendly we met one at the Oshawa Generals game and my daughter got the hall to pet it it seemed like it really it all seemed like really nice little dog in way this one doesn't seem as nice he might have rabies then of course kung-fu chimp the ultimate mammal anyway that's it and you know what grinds Peter Griffin's gears six would tell chickens with attitudes if you've ever watched the Family Guy every so often Peter and this chicken they just have this epic like three four five minute fight that takes up good chunk of the episode but it's it is it's wicked battle anyway that's it hope you enjoyed the lecture if you have any comments you can comment below the video here in the comments section or go to Ed's being it can ask questions there hope you enjoyed the lecture and learn something we'll talk again soon all right bye bye