hi um it's getting a little fuzzy as to where things fit so this recording is probably what would have been in the podcast but i don't know anymore um it always depends on where i get to in lecture what goes into the podcast so what we're going to talk about now or next i guess is the uh innovation of the different feeding mechanisms so if you remember some of the characteristics of animals revolve around the fact that they're chemoheterotrophs and they have to have ways of getting on food so there are a couple things that we sort of identify as trends in getting food in general but there are also the diverse groups tend to have a few things in common that allow them to get food so the first thing i want to do is remind you we're trying to talk about why some groups represent more of the pie than others and so let's get on and first let's talk about what how we actually get food in um in animals all right so first we have a lot of different ways that animals go about getting food and on this list that you see on the side are a whole bunch of them um terms associated with acquisition of food and when we talk about these there's some terms that are going to come up and have come up already but let's go ahead and just start with the list and define these things as we go so in terms of things like sponges and often organisms that have flagella or cilia that trap food we have this process called filter feeding and so in most cases filter feeding includes taking materials from water trapping food in them and then using that trap to obtain your food and so when we think about filter feeders we're often thinking about like the way we talked about the sponges drawing a current in through the body and then we talk about it then the cells trapping the food that's in there okay um so in the top left panel you see an organism that uses structures that filter water around it and then trap that food so typically we also have uh the characteristic of filter feeding where the organism is feeding on something that's that's smaller than itself and suspended in water or air so most of the organisms that are filter feeders um are going to be aquatic and they're basically straining their food so even the in panel b that you see underneath directly underneath the a in figure 29.8 that's a baleen whale and it has a structure that goes across its mouth that filters small uh animals into it and then it actually is just basically removing that food from the filter to digest it so it isn't something that's limited to small organisms or organisms that have these fancy uh fancy flagella or cilia-like structures it also can have a fancy structure like the baleen whale does sometimes you'll also hear these called suspension feeders but it's just it's about the same thing all right so other animals rely on feeding on plants we call those organisms herbivores herbivores can be anything from aquatic to land animals but they rely primarily on eating plants and so i put up a picture of a caterpillar that likes to eat plant materials to grow into its adult form we also have predators like the crocodile you see down at the bottom left that one is taking out a very large herbivore um and then we have omnivores you kind of fall into the omnivore category because you get your nutrients both from plant material and animal material and fungal material if you can consume all those different things you are an omnivore but animals also fall into the categories of parasites so parasites are typically animals that feed off of other living things it can be a long-term relationship or the parasite can actually kill its prey or it's excuse me it's host i want to emphasize that when we talk about parasites we're typically they can be external parasites or they can be internal parasites but when we're using that term um we're talking about an animal that can kill and eat parts of its its host even though the host is much bigger than it um and in your textbook it it also refers to um the size of the organism so typically the parasite is much smaller than the the post the organism that it is eating or killing is usually referred to as a host um whereas with a predator relationship the animal that is being eaten is called prey and it typically results in predators are killing their hosts but parasites don't have to um it's a little bit different but typically it's a harm more harmful both parasites and predators are harmful to the organism that's getting eaten but the primary difference i think is that the parasites are much smaller than their host species um so you can see a parasite there's a horse hair worm devouring a cricket in figure 30.17 and lastly we can talk about detritivores and so when we talked about fungi it gave you the definition of detritivore as an animal so it's a specific it's a category of animal that ingests [Music] dead decaying matter uh often it refers to a detritavar is often something that's eating dead plant material and some people are very specific about that uh one example of this is something like a tadpole that's a larval frog where it skims the rocky bottom of where it's living and it's actually eating off the bottom and there's several animals that live this way they are super important in dealing with elimination of dead organic matter okay so these are sort of types of animals we can have we can be more specific and we could talk about sap robes as well there are some animals that live as saprobes remember saprobes are organisms that live off of dead decaying matter whereas a detritivore typically is an animal that lives off of dead decaying matter both all of these fall into the category of of um organisms that live off of dead decaying matter and that can include they can be part of the decomposer community okay so what we're going to try to discern from all the stuff i'm going to present about animals feeding is that when we think about the evolution of diversity in the clades there's sort of a couple different ways that animal clades seem to solve the problem of eating and i sort of wrote these out as bigger longer texts than i normally would but just to give you an idea of what we're going to look at we have a couple different categories first some animal clades have a single unique structure that's used for all members of the clade and the example i have listed here is pneumaticist that i'll show you in just a second but this structure doesn't always undergo massive modifications and it's sort of when they are it seems like when they're limited by these the clade isn't as diverse as when they have a structure that's modified among groups so we have a lot of examples where clades that are diverse have one structure that gets modified in a lot of different ways to exploit different food materials so that often triggers a whole diverse group of organisms another way to become diverse is not to take one structure and modify it but instead to have a whole variety of different structures in each each clade of organisms and so there are three kind of things we have a unique structure a modification of one structure and then novel structures in each group of a clade and so we'll look at some of these as as we walk through different clades of animals and you can see that in the two diagrams i have i'm showing you different ways that appendages have been modified to help assist in getting food okay so when we talk about these specific structures i'm just going to highlight a couple different ones just to give you an idea of what we mean so cnidarians include jellyfish hydra and a few other organisms and the way that they capture their food is they have a specialized cell called a nidosite anytime you see the ending cyte like you saw in sponges um and here it refers to a cell so anytime you see cyte it's a cell and this cell is unique to united arians so it's called a nidocite so the pref the prefix of the site is just to describe cnidarians and this structure within the cell you have a structure called the demacist so you can see the whole cell is called a nidosite and it has this structure that it can flip inside out and use to sting its prey so when a normal a nidocide is sitting before it's being used it would look like the black and white drawing on the right when it's being used to paralyze prey it gets averted and this whole tube can come out hit the prey item and then in insert toxins into the prey so in the diagram of the portuguese manowar you can see that in the in the tentacles it has trapped a fish and that fish has been poisoned by the pneumaticist so if you've ever been stung by a jellyfish this is what's happening this um tube is being everted out of the cell it's entering into the tissue and injecting some sort of toxin so all cyderians do this this is how they capture prey they kill it first and then once they can immobilize it they can digest it similarly in ribbon worms they have a structure called a proboscis so ribbon worms are long skinny protostomes they have this specialized structure that they store in their body that's ejected by muscles and they use that to trigger and capture their prey okay all right so one of the favorite organisms remember in that characteristics of animal slide i showed you what a velvet worm looks like so velvet worms belong to a clay called anacophara and what they do is they spit glue and this actually they have these modified mouth parts that specifically spit out this chemical that traps their prey and the link that i'll i'll put up when i put the link to the video up um it's really crazy to watch because they spit out so much glue and it traps the prey items other insects typically in this glue and then the mouth parts will come up and actually rip apart the insect when it's trapped and so that video shows that really well okay so these are three examples of specific very specific methods of getting food now within the clade lofotrochozoans so if you look back at that phylogeny from figure 29.1 low photrochozoans are a group of protostomes that include things like flatworms bryozoans rotifers the ribbon worms i just showed you and annelids and mollusks so one of the cool things about loaf trochazoids is they all have this uh ciliated structure at least at some point in their life and in many cases um this this ciliated structure is used for feeding so in the organisms you see shown in these diagrams so um the picture in the top left is a bryozoan the cartoon-like drawing is a um uh rotifer and the picture at the bottom right is another uh it's a brachiopod and then in the right is a faronid so these are very uh not very diverse groups of organisms but but each of them themselves have a modification to this ciliated feeding structure so um called the lofaphor and the loafor gets modified to have uh these cilia that trap and capture food so a lot of these are filter feeders but they've taken that one structure structure the loaf of four and they've gone in and modified that structure so it does an efficient job of trapping food all right so that's an example where we have ciliated feeding structures that have modifications made to them another cool thing that happens in terms of um trends we see now this isn't for diversifying a single clade but what we often see when animals are parasites they they rely on being able to enter their host get into their host and then digest the tissues of their host so they can have specialized structures for attaching to their hosts so in the um arrow worm you see the spines at the top you see those in tapeworms as well that they attach to the tissues of the host so that they actually stay there and can break down the food in things like flatworms what they've often done is their whole goal is to just seep the nutrients off of their host so they actually don't need to do anything but really reproduce and digest so if you look at a parasitic worm compared to a free living worm you'll see modifications to deal with whatever tissue they've dealt with in this case i believe this is a parasitic blood feeding tapeworm so it is better at digesting blood uh others like or sorry flat worm not tapeworm others like the tapeworm have very thin bodies so they're basically hanging out in the intestine of their host and absorbing nutrients through the body wall of um the animal and it becomes really flattened so what you see in um the free living flatworm on the left and the parasitic flatworm is the the flat the parasitic ones tend to be more flattened with the ability to just absorb materials through their body or they have a specific attachment structure that allows them to get food from their host an alternative strategy is used by this group annelids and so anilids are segmented worms and they have four well-defined clades each of them is represented in this diagram and they each are doing different specific food feeding and i've listed what they i show what the type of feeding is on the right bottom so earthworms are an example of an anilid that uses a feeding mechanism called grazing and what they do is they're actually going through the soil and they're kind of chewing on the dirt and scraping materials off of the the dirt so they're grazing at the top that fan like animal is actually filter feeding so it has this unique feathery filter structure that it can use to filter materials out of the water column leeches are another example of an annelid and they feed explicitly on blood and have modifications to have a sucker to attach to their host so it's a parasite and then it has specif has uh a chemical it secretes into the host to prevent that blood from clotting and then it can take in the blood and digest it in its body and then lastly at the top is sort of one of the most terrifying worms i think we can imagine where it has this beak-like structure that's heavily keratinized really sharp and actually is a carnivore that eats other animals so in these guys instead of having one structure that gets modified into different set of feeding approaches they've actually got all wildly different approaches in different clades of the organisms you see that similarly in echinoderms so echinoderms are they have several subdivisions in them and in each of these pictures you're seeing um [Music] different representatives from those clades um so at the top is a sea star and what it is doing is it's going in it's taking a cl a bivalve muscle that has two shells it will go in and grab onto that muscle pull it apart with its tube feet and then it can flip its mouth inside out and put the materials inside the mouth and pull it back into the body so those guys are predators we also have organisms like the sea cucumber where it has modified structures at the top that filter feeds so you can see those sticking out it's the purplish one at the bottom left purple blue ish um and then we have grazers so both the um both of these pictures the other two pictures are sea urchins and sea urchins they use their water vascular system to do this gas exchange but at the bottom of that little ball they have a structure that's been uh highlighted in the bottom right picture that's white and it's these sharp uh elements inside their outside shell that scrapes along the bottom of it would be scraping detritus off so it's a grazer as well and so it scrapes that off and uses food that way so again three totally different methods just like in annelids where they have unique ways of getting food and using their organ systems differently in contrast if you look at mollusks you have um remember mollusks when we looked at the body plan have several structures in them that are consistent like the mantle the radula the muscle muscle muscle muscular foot and the shell in the case of mollusks what we see happening is that the structure called the radula is um modified in each group of organisms to feed in a different way so with the exception of the bivalve so those are any shelled mollusk that has two shells they filter feed and they don't use the ratula and they don't even have one so they basically are opening and closing their shells and filter feeding in the other groups of mollusks that would include things like snails slugs octopus squid um did i forget anybody well the kittens that we looked at as the generalized body plan like you see in this picture here they can be grazers so if they're using the radula like it's shown in the diagram they are using that to scrape along the bottom scrape detritus off or scrape along the surface of something so sometimes you'll see on a really slimy rock you'll see the trail of a snail that's used its radula to scrape off that material off of a of a rock so that's the common use of the radula and these are just hard structures that can scrape they're called the radula teeth they are not teeth they are controlled by muscles within the cell within the um chitin or within the snail the radula encephalopod so that would be squid and octopus have modified their radula into a beak and so it's this sharp structure that they can use to pull apart things like bivalves and then they use their tentacles also to manipulate their food so they have taken that radula modified it and created a new structure called the beak okay so that's an example where most mollusks have taken the single structure the radula and manipulated it into different structures similarly arthropods have done something to make um their different approaches to finding food and this is so this is kind of an interesting one because it's tied to the evolution of segmentation the evolution of paired appendages um and so when you tie those two things and the muscles right so we have three things we have evolution of mesoderm evolution of segmentation and the evolution of paired jointed appendages and arthropods have taken that and generated many new feeding modes many of them are new feeding modes that use the paired and jointed appendages to manipulate their food and so i've picked out several different arthropods here because i want to point out the differences among them and how it's allowed them to use different structures so first in the head structure of many different arthropods you have modified modes of getting food into the body and so some of them have these long proboscis like you can see the ones feeding off of the nectar in a flower some of them feed off of pollen and some of them feed off of blood like in the mosquito so they use that structure to feed off of things so that's a modification in the head structure and the same with the little green aphid now that little green aphid is a little tricky it's feeding off of phloem in the leaf that it's on some of some of these aphids have done weird things like secondarily acquired photosynthesis in their bodies so they actually can generate some of the food themselves in other arthropods we see massive modifications to their limbs and so in their limbs they have joints in them so they can walk and move and that's new in arthropods and they also have made with the repeated legs this their legs can if a change happens in their legs it's okay because they have other legs they can use to walk right so when you look at something like the crayfish it has those um grabbing limbs where i can manipulate in this picture of fish and hold onto those and then eat them and things like spiders these are funnel web spiders from australia they have these massive fangs where they can uh inject prey but then they can use all of their different modified appendages to manipulate that food okay so this is one that's tied into all of these each of these things evolving uh at different times and kind of maximizing their use in arthropods now i also put up a picture of the the barnacles mostly because in the barnacles you have [Music] filter feeding so they have these structures that come out and actually filter feed so these guys aren't segmented they don't have limbs but you know they're arthropods because they have that segmented larval form so in anima in vertebrate animals typically what's really being modified to help them manipulate their food is the jaw so early on in fishes there are bones along the jaw that held open their mouth and held open their gills and so what they're doing when they swim is pushing water across their mouth and that as it enters their mouth it also exits out their gills and that happens in sharks that happens in lampreys but over time those gill arches the bones that surround the gills actually became more ossified or they became more bony and they also had muscle attachments to them that allowed them to open and close their mouths all right so when we look at early fishes so in the diagram you see down on the right and the bottom you have early jawed fishes that are called placoderms almost the entire gill arch is now this massive bone that allows them to open and close their mouths those bones have been modified in many different groups of uh fishes to open and close that jaw and as we then transition onto land those bones in this in the skull actually serve as a point of muscle attachment so when you look at i'm not asking you to memorize the different types of skulls what i want you to recognize is that the bones that are that are in the skeleton of vertebrates are used to attach muscle and that muscle allows the jaw to be used to feed on different materials now in some things in things like uh diopsids like reptiles those jaws are incredibly powerful and can actually take out their prey like you see with crocodiles and things like that you are a synapsid you have a single opening in your your skull other than your eyeball opening and diopsids have two and each of those different muscle attachments allows a different use of the jaw for vertebrate feeding okay so we do know that this is a sort of a facilitator of different access to different food types all right so in vertebrates and in arthropods we have this modification of the structures that we have to diversify our group give us new kinds of food to eat okay so we've been talking about getting food and i already introduced the idea of paired jointed appendages by talking about arthropod feeding modes but i want to talk a little bit about tying together paired and jointed appendages with segmentation and how it allowed other things to happen so early on when you look at all of the animals that um are in the phylogeny and figure 29.1 many if you just look at the lofatrocozoans for example that would include mollusks and annelids and worms and flatworms things like that you have a lot of worms in there and then when you with the exception of things like octopus and squid none of those organisms have appendages appendages arose in actizones and they first showed up in tardigrades and in velvet worms so velvet worms the animal on the top and the one that spits glue and below that is a tardigrade and notice also that so we had segmentation evolve somewhere around annelids but it really got specialized when the animals like these shown here gave rise to tardigrades velvet worms and arthropods so tardigrade developed worms and arthropods are all segmented and one of the things in tardigrades and velvet worms that you see is associated with each segment is a pair of legs so in the case of velvet worms and tardigrades those legs are filled with fluid so they're they're held open and they're able to move and help them walk because they push fluid in them and that allows them to move forward so when you look at that velvet worm video you'll really see how they use those legs but in all of these guys and all the species of velvet worms and tardigrades their legs are just doing exactly the same thing every pair of legs is doing the same job but what happened in arthropods is that they developed appendages that are paired they still have them on either side of the body but they have joints in them and those joints are controlled by muscle movement so when we have the paired jointed appendages evolve in arthropods they use their the evolution of segmentation right because they have these repeated segments that got modified they have different limbs associated or different paired and jointed appendages associated with each of their tagma we talked about those are the fused segments that occur in arthropods they can either be the head the thorax and the abdomen or the cephalothorax in the abdomen um and what happens is this association of these jointed appendages with different functions and i think when you look at the grasshopper it's pretty simple you have two walking two sets of walking legs and a set of jumping legs in the crayfish you have many different leg types and all of them are jointed so they can do different things so they have the maxilla peds to help hold food they have peripods to gather food they have walking legs swimming legs and this allows them to not just move about and get food but it also allows them to get onto land okay so this is a massive transition and we see it repeated in early vertebrates so early vertebrates while they do have they are segmented organisms their appendages really are associated with the evolution of the bony skeleton and specifically bony jointed limbs so when you look at something like a shark it is not a bony animal it has made of cartilage and it has paired appendages and this picture is nice because you can see the two paired fins at the base of the shark but those are actually not bony there's not any there's muscular support in there but there's not bone so there's no joint in there to move but in the groups of early fishes um like lobe-finned fishes the lobe-finned fishes started to have bones uh appear in their fins about 380 million years ago and those bones changed as time passed on and as these organisms started to put more weight on them and move on to land early amphibians you can see how the bones have changed from the time that they started in lobe fin fishes two they became walking legs all right so we can actually see the development of these bones being tied to uh early bones in the lobe finned fish and just like in arthropods the development of this bony muscularly attached set of limbs allows them to move onto land so we have a two independent cases where bony or sorry paired jointed appendages evolve in organisms that allowed them to exploit land okay all right so i'm going to stop there and i will post this one up and move on to whatever the next one may be