hey guys I'm coming at you from a slightly different location today but our topic is still a good one as always please make sure you are filling out your notes organize your as you watch this video today's video topic is kingdom Animalia we're gonna be looking at the characteristics of what makes an animal and animal why would an organism belong to this kingdom we're gonna look at some of the body plans and anatomical features of animals as we look at the most simple to the most complex and then we're gonna look at how we use that information to classify animals so let's start by just talking about what makes an animal and animal why does an organism belong to the kingdom Animalia as you remember kingdom Animalia belongs to the domain Eukarya so all animals are eukaryotic their cells have a nucleus and they have a membrane-bound organelles our animals are multicellular which means they're made up of mini cells all animals are heterotrophic which means they have to consume other organisms in order to obtain their energy and most animals do reproduce sexually but a few reproduce asexually and a few reproduce it in both ways and then all animals are able to move and I'm going to put a little star next to that statement because for a few animals that's just like during their larval stage of their lifecycle but all animals are able to move at some point in their life cycle so let's refresh our memories on some animal cell structures remember animal cells do not have an outer cell wall the outer cell covering is just a cell membrane there every animal except for sponges cells are organized into tissues and then for the majority of your animals they go into more complex systems so tissues form into organs and organs form into organ systems and those organ systems work together in our more complex animals to form the entire organism but depending on the animal and depending on what the cell is being used for different animal cell structures have specialized features to them for feeding for digestion for protection and that sort of thing now you probably have heard that animals can be served groups into two major categories invertebrates and vertebrates the majority of your animals 90 to 99 percent of animals we we don't know all the animals that exist in the world but but most of the animals are what we call invertebrates that those are animals that do not have a backbone the majority of invertebrates do have what we call exoskeletons or sort of skeletons on the outside of their body except for a kind under arms those have endoskeletons but for the invertebrates that have exoskeletons those are outer coverings which serve as some sort of support framework they provide protection they prevent water life but the thing about exoskeletons is they don't grow with the animal so they have to be shed as the animal grows your other major category of animals are vertebrates which is much fewer in number you can see on this slide here here would be your mammals and other vertebrates so very small in numbers compared to our invertebrates those do have a backbone and they contain what we call endo skeletons or skeletons on the inside that and this is an internal framework that grows with the animals so we obviously don't have to shed our skeleton as we grow it grows with us now what the skeleton is made up of can vary from cartilage like in sharks and in stingrays to bone like isn't is it nuts okay so here this would be examples of invertebrates and these would be examples of vertebrates with endoskeletons now animals we know can be found all over the earth anywhere there is capable of life being supported you're gonna find animals there so everything from marine water is from coral reefs to the benthic zone to fresh water from rivers and streams to lakes and ponds to land right our terrestrial ecosystems from deserts to grasslands to rain for us to polar ice caps you're gonna find animals in all of those places now remember we talked too quickly about reproduction and I said I have to put a little star next to that most animals do reproduce sexually utilizing either internal fertilization or external fertilization internal fertilization is when the sperm and the egg join as a zygote the fertilized egg inside the animal's body external fertilization and you're gonna hear me use these terms a lot so it's important that you understand what they mean external fertilization is like what's happening in this picture here where the female releases the eggs into water and then the would release the sperm into the water as well so the sperm and the egg form the zygote outside of the body now this is going to only happen in animals that either live in the water or they're gonna lay their eggs specifically in the water but it does require some sort of aquatic environment and then for the organisms for the animals that reproduce asexually some animals actually are what we call hermaphrodites meaning they're capable of producing both egg and sperm earthworm would be an example of that our other forms of asexual reproduction and animals you have animals that are capable of budding like a sponge or coral fragmentation which would be like a starfish breaking off and then regenerating that's a sexual representation as asexual reproduction as well so an animal that is capable of producing a new animal from the same one single parent okay now let's get into a little bit of animal development details so the fertilized eggs of most animals the zygotes of most animals follow a similar pattern of development so first of all we have our zygote which is our fertilized egg and it starts to undergo mitosis so one cell becomes two cells and two cells becomes four cells and so on and so on and so we have the formation of an embryo which is that little ball of cells from two cells until you have a ball of cells then the embryo that little cluster of cells is going to form what we call a blastula and basically this is where the ball of cells fills with fluid and becomes almost like a hollow bubble of cells on the outside fluid and the inside that's the blastula stage so like this picture right here then in all animals the blastula is going to start to pinch in and that's gonna form what we call a gastrula and that sort of like it's gonna form like a double bubble right a bubble within the bubble and that's gonna be really important as you get into your more complex animals what happens after that stage but all animals sort of follow this similar sequence of events so the zygote then the embryo then the blastula and then the gastro lobe now the gastrula is going to develop into different tissue layers so the inner cell layer is going to form what we call the endowed and in most animals that's gonna form the digestive organs and the digestive tract lining and then the mesoderm which is your sort of like more complex layer that not all animal gastrula are gonna form this is gonna be this is gonna form more complex organ systems and like different muscle tissues so not all animals have that mesoderm layer and then the ectoderm layer is the outer cell layer which is going to develop into nervous tissue and the skin of the animal okay this is a really important diagram and something that is really important to understand so make sure you fill this in on your notes organizer animals are classified by how their tissues develop which we just briefly talked about we'll talk about more in detail their body symmetry their body plan they are body cavities how they digest food and their different anatomical features so go ahead and take a minute to pause on the slide and fill in this chart on your notes organizer so let's talk quick you're gonna hear me talk a lot about animal symmetry as you learn about these different animal groups so it's important to understand why we're looking at symmetry and what type of organisms you would see each of these types of symmetry the type of symmetry an animal has really allows it to move in certain ways so symmetry when I say that I'm just talking about the similarity or balance among body structures of an organisms so animals can be asymmetrical they can have a radial symmetry or they can have bilateral symmetry asymmetry means that their body cannot be divided evenly across a central front plane or an axis in any way it's never gonna sort of fold in half and be equal on both sides so examples of animals that have asymmetry would be like sponges and corals so here's a sponge here's coral this doesn't allow for movement right these are more sessile or non moving animals remember they can move during their larval stage but at this point in their lifecycle they don't have any body symmetry which means that they sort of have to plant themselves in place radial symmetry is when a animals body can be divided along any plane through a central axis into roughly equal halves so think about animals with radial symmetry their bodies sort of raid Yates from a central point right so that would be like a jellyfish or a starfish or an anemone animals with radial symmetry these this typically allows for very slow movement very simple animals that don't need to sort of hunt for prey specifically they just need to be able to detect and capture prey in any direction at any time this type of animal only develops from ectoderm and endoderm they don't have that more advanced mesoderm and then there are some anatomical terms that are gonna come along with organisms that have radial symmetry so if you hear me refer to the oral surface I'm talking about the surface of the animal that has the mouth so I want to starfish that's the underside right it's always gonna be the underside of an animal with radial symmetry or the abhorrest which is the side opposite the mouth so the sort of side you would see on a starfish if you were looking down in the water hey then we have animals that have bilateral symmetry and this is the sort of most complex form of symmetry you're going to see this in more complex animals so bilateral symmetry is when the body can be divided into mirror image halves along one plane through the central access so examples are worms insects crustaceans fish amphibians reptiles birds mammals humans right we have bilateral symmetry you could sort of cut us down the middle and we'd be roughly the same on either half this is gonna be seen in your more advanced animals because this is an adaptation for movement in a specific direction this is an adaptation for animals that are what we call hunters right they want to find their prey and be able to move easily in that direction so animals that have bilateral symmetry they've developed from all three of the tissue layers ectoderm endoderm and that more complicated mesoderm layer as well animals that have bilateral symmetry exhibit what we call cephalization which means they sort of have a thinking end ahead in with some sort of concentrated nervous tissue either like a brain like what we call ganglion or an actual brain but they have cephalization a head region so this is gonna require us to use some different anatomical terms as well so for an animal with bilateral symmetry if I'm talking about their anterior end I'm referencing their head end the opposite end would be their posterior end so you can see on all these diagrams here anterior and posterior and that looks a little bit differently for organisms that are like tetrapods sort of walking like this versus animals that are more upright like we are okay then the dorsal surface would be the back surface of the animal with bilateral symmetry think of the dorsal fin being the scary fin the fin you don't want to see in the water right so their back fin and then the ventral surface would be the side opposite that which is the belly surface and then again with animals with bilateral symmetry their body cavities can vary in different ways they can have a more simple sort of sac like body cavity that has a single opening so food and waste are going through the same spot or they can have a more complex tube like body cavity with two openings this is where you know food comes in one in the mouth and then waste goes out the other at the anus you're gonna have a more complete digestive system which means they're gonna be able to obtain nutrients more efficiently and effectively so we give we give those some terms if an animal has a solid body without a fluid-filled gut we call it an AC limit these animals like flat worms for example this picture here are gonna rely on just simple diffusion in order to move gases and nutrients throughout their body pseudo cela mates and those are gonna be like your round worms are gonna have a fluid filled gut but it's only gonna be partially lined with mesoderm meaning they're not gonna have like internal organs also lined with the the mesoderm tissue layers and then true coelom Eights which is basically gonna be everything after mollusks and segmented worms they're gonna have a true fluid filled gut that is lined with mesoderm and also encloses all the organs with mesoderm as well this was a key adaptation for more specialized structures more specialized systems within the animal and then to further classify cela mates their embryonic development can develop in two ways they can have protostome development which is where the mouth develops from that first opening in the get and the gastrula so if a mouth develops here that we're gonna say that that animal has protostome development so that's gonna be like snails earthworm spiders things like that more simple animals and then if they have deuterostome development it's actually the anus that develops from that first opening in the gastrula and this is gonna be your more complex animals like mammals and birds but also the echinoderms and invertebrates which is why going back to this cladogram right here that i showed you earlier we think that echinoderms are more closely related to vertebrates mammals humans than any other invertebrate because their development is more similar and they share more similar characteristics okay so what I want you to do right now is I want you to attempt to answer these questions using the chart that is on this slide so which invertebrate animal group isn't as a coelom eight what are the characteristics of a mollusk chordates are vertebrates are most closely related to which in vertebrate animal group which is the answer I just gave you which in vertebrate animal group has the only animal are the only animals without true tissues and what do annelids and arthropods have in common and see if you can answer those questions and that's all I have for you today hope you have a great day bye