Invertebrate Characteristics and Phyla

when you think of animals what do you think of the big charismatic animals of the African savanas the cute red pandas at the zoo the animals you may see on farm these are the animals that most people think of the vertebrates but the truth of the matter is over 95% of all animal species are invertebrates and most of those belong to only eight Fila there are 34 Fila of invertebrates some only containing single species while another philm contains nearly 85% of all animal species in the world today we're going to concentrate on the major characteristics that makes an invertebrate an invertebrate and we'll be looking at those eight most common and recognizable Fila of invertebrates first what exactly is an invertebrate well invertebrates are animals in the kingdom Animalia that lack vertebral column or backbone some of the characteristics that help us put invertebrates into categories called phym are the animals body plan or symmetry if the animal has head or not and the way it digests its food and vertebrates have three basic body plans called symmetry if it has two similar hats like we do then it has bilateral symmetry if its body parts are arranged in circle around central point it has radial symmetry then if it seems like there is no symmetry at all this is called asymmetrical symmetry the simplest of all animals have asymmetrical symmetry the sponges many people just don't realize that sponges are in fact fact animals sponges are in the philm peripher and in fact are cile or immobile animals that lack nerves in fact they don't have any organs or organ systems at all rather they are made up of grouping of cells that work together to meet the survival needs of the sponge these cells are supported by skeleton of spicules which are slivers of carbon carbonate or silica just like us sponges have EP theal cells in their case these cells are called porocytes these cells connect the outside of the sponge to the inside cavity the water flowing through these cells transport Plankton through them and this is what the sponge eats not crabby patties as animals become more complex we start to use the other characteristics mentioned before let's take look at filum called nidaria the jellyfish corals and the Sean enemies all nidian exhibit radial symmetry and have tentacles around their mouth and stinging cells in fact nidaria comes from the Greek word of nidos which means stinging nettle these cells are called nematocytes which give the film its name these cells inject Venom into their prey or potential Predator these animals can reproduce either asexually or sexually and can be free swimming Medusa forms or cile polyps some species exist as both forms at some point in their lives Coral is very unique narian these animals form massive colonies called reefs the largest being the Great Bear Reef off the coast of Australia this colony of invertebrates stretches over 1,400 mil over an area that covers 133 square miles these corals provide habitat and nesting grounds for over million marine species making coral keystone species for our oceans without them our oceans would not be what they are today the first time we see bilateral symmetry is within the philm platty helment these or simply put the flat worms these unsegmented worms like body cavity other than the mouth and anus they also lack respiratory and circulatory system so how do these organisms get the essential oxygen they need if they don't Breathe In Like Us well it's process called diffusion and oxygen molecules can diffuse use through their skin this is also the first time in the animal kingdom we start to see head sometimes with distinct eye spots most flat worms are parasitic think about the parasitic tapeworm that's flat worm and that's why you should probably put your pets on regular Dormer but other flat worms are free living which feed on bacteria smaller worms and even dead organic matter another phm that exhibits bilateral symmetry but has more of cylindrical shape is the phm nemat the round worms these parasitic worms are some of the most abundant animals in the world having over 28,000 different species with around 16,000 being parasitic nematodes also lack respiratory in circulatory system but are more complex than the flat worms in that they show tissue Lev level organization they are sexually dimorphic meaning that there is difference between the male and the female and can reproduce either sexually or asexually these worms can live in aquatic environments in our soils and even inside other organisms the species that aren't parasitic can feed on fungi bacteria other roundworms and even some of our insect pests in our garden they play very important role in nutrient cycling of our ecosystems but can also feed on plant roots inhibiting growth what about worms that have bilateral symmetry have organ system organization have well-developed circulatory and digestive system and have segmented bodies well they have their own philm philm and Alita these 177,000 species of worms can live in Marine freshwater and terrestrial ecosystems most analid worms are hermaphroditic meaning that they have both male and female reproductive organs they also can reproduce sexually or asexually if you have ever been fishing you know that some of these segmented worms make for great bait like earthworms and leeches 23% of all marine organisms belong to single philm the second largest philm of all animals the mollusk or phm molesa this fym consists of some of the widest range of body forms of all invertebrates most have head soft body mass and muscular foot all mlls have one or all of the following characteristics radula calcium carbonate shell and mantle the seop pods are the most advanced mollus in that their heads are very welld developed and have sophisticated sense organs and their foot is modified into prey capturing arms other mollus include snails slugs squid muscles and clams very recognizable film of invertebrates simply by their shapes and skin are the kind of derms phm echinodermata philm that is exclusively in Marine environments this filum includes all the starfish sea urchins sand dollar and sea cucumbers and the word eodm translates to spiny skin echinoderms have structure called an endoskeleton made up of calcium carbonate these species date back clear to the Cambrian Period 500 million years ago their diets can range from herbivores like sea urchins filter feeders like sand dollar and even Predators like starfish these Predators will prey on muscles Coral clams and even other echinoderms now to talk about the of invertebrates that is most recognizable to most people phm arthropoda which translates to jointed foot this massive phm consists of nearly 85% of all animal species in the world and all of them have an exoskeleton which is protective outer layer made of kiten the same protein that makes the cell wall of fungi they all have segmented bodies jointed appendages bilateral symmetry dorsal blood vessel and ventral nerve cord arthropods can be divided into four major groups the myriapods which is group that has one pair of antenna and multi- segmented trunk with multiple pairs of legs the most recognizable being the millipedes and the centipedes then there's the tastiest of all invertebrates well maybe that's just my opinion but let's talk about the Crustaceans group with two pair of antenna more than five pairs of Limbs and have gills most Crustaceans live either in Marine or freshwater ecosystems but some live in terrestrial environments this group includes crabs lobsters shrimp crayfish sand fleas Barnacles and pill bugs or simply rly poy most people's least favorite group of course are the arachnet this group consists of the Scorpions pseudo scorpions mites ticks daddy long legs or harvestmen and of course the spiders aragn do not have antenna wings or claws it'd be kind of terrifying if they did instead they have eight limbs and fused head and thorax called seph thorax and finally the largest group of arthropods class and secta these arthropods all have six legs compound eyes and pair of antenna this is by far the most familiar group of arthropods these animals live everywhere except the oceans there's even species that lives in Antarctica if you recall from the domains and kingdoms video if you don't then you should probably go back and check that one out classifying animals goes domain Kingdom philm class order family genus species right now we are in the film arthr and class and secta but there are over 30 orders including the orders of flies bees wasps and ants beetles moths and butterflies grasshoppers true bugs and many more each serving important ecological functions we wouldn't be able to function as Society without in fact all of the invertebrates that we talked about today serve these functions functions like pollination decomposition being both predator keeping the ecological balance and prey supporting other species they clean our Waters they're important at recycling nut nutrients in our ecosystems they build our precious coral reefs you can easily see just how important invertebrates are to us and our natural world hope this video has helped learning about invertebrates and you have better understanding as why you should think about invertebrates more instead of just the big charismatic animals be sure to subscribe to learn more about our natural world and all other Sciences