Phanerozoic Eon paleozoic protostomes PDF

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Phanerozoic Eon – Paleozoic: Protostome Invertebrates    

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Cambrain: 550-488 Ma Ordovician: 488-443 Ma Silurian: 443-416 Ma o Singled cell ocean plants start to move closer to land, along the shores Devonian: 416-359 Ma o “The age of the plants” where there are many terrestrial plants o Has lignin in plants: not able to break down, plants die and get turned into fossil fuels Carboniferous: 359-299 Ma o So much plant material and turned into fossil fuels Permian: 299-245 Ma

Cambrian and Ordovician  

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There a pieces of continents that are floating around Continental mass: Laurentia o Has continental shells which are shallow enough for light and nutritional supply o Has the potential to be incubators of variety and diversity o Is also sitting on the equator: best temperatures and the most light Odd species that are “experiments” to invertebrate life Burgess Shales o A giant deposit of fossils that is very well preserved o Many unusual invertebrates o Fossils found are the very first forms of multicellular life o o

Able to compare to different continents because of the moving of terrain and see that the diversity is the same Colonial choanocyte ancestor  Consists of a cell body with finger like projections (microvilli) that make a collar around the cell with a flagellum. As the flagellum beats, it creates a water current that flows through the microvilli which allows different aliments to get trapped in the microvilli and the aliments gets digested through phagocytosis and that is used for nutrients  Usually in clusters or mats  More choancytes together means they can pump more water than just one alone, an emergent property  This means more water flow, more access to food and a higher fitness

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Collar is unique, the microtubules in the microvilli of the collar are the same across species, therefore we are all dependents of an organism like this Sits at the base of the fungi and Animalia

Autapomorphies of Animalia     

Multicellular eukaryotes Ingestive heterotrophs Cells with different functions other than reproduction Choanocytes -> closely related Collagen o Can’t find in other kingdoms, used to stick cells together

Animal Architecture 

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Tussues o Non, diploblastic (ectoderm and endoderm), or triploblastic  Blastic is the number of cell layers  Ecto, endo, meso o Mesoderm is always used to make muscles Symmetry and cephalization o Asymmetry, radial (symmetrical in multiple cuts), and bilateral symmetry (only one way to divide the organism, symmetry in one way) Emryology o Protosome and deuterostome Body Cavities o Coelomate, pseudocoelomate, acoelomate

Porifera Autapomorphies (Sponges)   

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Use of choanocytes in an aquiferous system o Cells are behaving independently and there is no coordination in between cells Cells but no tissues Totipotent cells o Any cell in the body can turn itself into any of the other cells in the body if required o This is an organism that is made up of stem cells that are specialized to different functions Asymmetric body plan o Dividing the organism from the mouth to the butt. This organism doesn’t have a mouth Consists of a mass of cells Chonocytes are lining the inside of the sponge. The wall of the sponge is perforated, so the water passes through the perforations and the beating of the choanocytes create a current

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On the surface of the sponge (pinacoderm) made of pinacocytes that stick together to create the “skin” of the sponge Porocytes create the holes in which the water travels through There is a jelly-like matrix is the adhesive surface so the cells can stick to it (mesohyal) o Between layers The only feeding cell is the choanocyte. Feeds by phagocytosis. Amoebocyte turn into any cells that are needed in the sponge Skeletal elements called spicules that can be made out of glass, protein, etc. The interlocking needs give the cell shape First animals that trap and harvest things in the oceans Sponge sex o Choanocytes become sperm Archeocytes (same as amoebocyte) (sponge stem cells) form egg Sperm is ejaculated into the ocean and then a “female” sponge makes a water current through it and takes the sponge No tissue, asymmetric organism o o

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Animal Innovations (Symplesiomorphies) 

Gap (septate) junctions loss of the choanocyte o There is a connexion complex that can open and close that can pass in between cells

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True tissues with all components internal digestive epithelium o going to have two cell layers

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Oral-aboral axis and symmetry Triploblastic mesodermal musculature Bilateral symmetry o There is still a group of organisms that is radial symmetric but still have a mesoderm

Gastrulation – digestive epithelium    

Hollow ball with one layer of cells and true tissues is called a blastula Second layer of cells is the result of the invagination of a blastula with created a gastrula There is now an opening and the cells on the inside are specialized for digesting No mesoderm, therefore no complex movements, radial symmetry

Cnidaria Autapomorphies (Jelly fish) 

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Cnidocytes o Unique to this group o Stinging cell o Contains a discharge organelle, turns itself inside out (has bars or toxins) and shoots out really fast. Was really fast and strong so it could feed off of the first arthropods o Like a taser Polyp body plan o A U shaped body with tentacles around it o Has two cells layers (Ecto and endo) o Made of true tissues o First skeleton in animals o Hydrostatic skeleton Epitheliomusculature o Has special cells that is a strand of muscle (myoneme) around the central cavity. The muscles in the epithelial cells are opposite from the myoneme cells o Uses like skeletal muscle because it doesn’t have mesoderm yet o Has a mouth but no anus, therefore incomplete digestive system o Invaginated inwards Polyp and Medusa (the one we see most often) o Mesoglea, a matrix between tissues Life cycle o Grows a polyp, some may be in colonies o Gonozooid produces little medusa jellyfish wish swim away and release gametes into the water. If inseminated, then a planula will form. The planula then forms a polyp o Planula has bilateral symmetry Corals? o o o o o

Found a fossil that was formed 600 Mya and Cambrian starts at 550Mya All coral reefs around the world are built of small polyps Coevolved with an algae and are now co-dependent on each other The algae has been killed off, therefore the coral does not have a symbiont Called algobleaching (in the great barrier reef)

Role of Skeleton 

To lengthen and contract muscles

Animal Innovations (symplesiomorphies)(two different steps)

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Tripoblastic Mesodermal musculature Bilateral symmetry Embryology o At the 4 cell state, they divide into an 8 cell embryo. o This 8 cell embryo can be in a spiral cleavage (top 4 cells are in the grooves of the underlying cells) or radial cleavage (cells are on top of each other) o Gastrulation  As the blastula invaginated to the gastrula, it created a mouth opening to the gut. The gut is now a second area in the cell  Blastopore: could have been the mouth or the anus  If the blastopore became the mouth, the organism is called a protostome  If the blastopore become the anus first, the organism is called a deuterostome o Coelom formation  As the gut is formed, the mesoderm fills the space between the ecto- and endoderm that created a body cavity. The mesoderm is solid tissue, not hollow.  Called a schizocoel  Another way mesoderm form: mesodermal cells form on the endodermal cells of the gut that form a little pouch and slowly gets bigger and bigger and fills the mesodermal space between the ectoderm and the endoderm.  This is calls an enterocoel o Protostomes ve deuterostromes  Protostomes  Blastopore mouth  Spiral cleavage  Schizocoely  Deuterostromes  Blastopore anus  Radial cleavage  Enterocoley  Two great lineages  But now proven false, so only the blastopore is the defining factor of the two lineages Body Cavities o Acoelomate  Mesoderm with no cavity (solid block) and no fluid filled space  Solid mass of mesoderm and the only visible cavity was the digestive tissue o Pseudocoelomate  Thought to be the intermediate between having and not having a coelom  There was a whole phylum that has this name

Mesoderm is associated with the outer ectoderm, but there is no mesoderm associated with the gut, therefore the only way to move food through the digestion cavity is to move the entire body of the organsim Coelomate  Mesoderm with cavity  When mesoderm forms, it forms simultaneously with a cavity, therefore came first  Mesoderm is associated with both the gut and the outer ectoderm 

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Protostomia (autapomorphy)  

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Blastopore is mouth 3 different groups o Ecdysozoa (animals that live within an exoskeleton)  When the organism grows and does not fit inside its exoskeleton, it gets rid of it and grows a new on (process is call ecdysis/moulting) o Lophotrochozoa  Lophophore or trochopore, never both  Lophophore: a feeding structure that is covered in cilia  Trochopore: larval stage  A taxonomic name where the group has one thing or the other  Wouldn’t have thought they were related, but when the genetic material was looked at, it suggested that they were related o Platyzoa  Primarily acelomate animals (flatworms) Ecdysozoa o Moulted protein cuticle o No surface cilia o Can be broken into two different groups based on the supporting structures of the proteins  Collagenous cuticle  Longitudinal but no circular muscles (mesoderm is usually in two sheets, one circular and one longitudinal muscles and they work together to create movement)  Epitheliomuscular pharynx  Dual valve system to let food into the gut without releasing it  Triradiate pharynx: the fastest way to open a structure is to part in 3 o Example: tricuspid valve in the heart o Triploblastic, pseudocoelomate, protostome, bilateral

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Nematoda  Using a whip-like movement to move between soil particles  Ascaris body cavity  Only animals that have amoebic sperm, no flagellum  Muscles are constantly contracting

Panarthropoda (autapomorphies)  

Cuticle with chitin o Acetyl glucosamine Food manipulated by limbs o Manipulates their food (preprocess) before digesting **Key event o May tear into smaller pieces o They use jaws, not limbs

Onychophora      

Oral papillae with slime glands Body wall musculature continuous sheet Unarticulated limbs Appendages are modified into antennae Tears and shreds food before swallowing and stuff Little claws

Arthropoda       

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Articulated exoskeleton of plates Muscles arranged in bands Compound eye Largest group of animals They all make their appearance in this time period Take the appendages around the body and fuse them together in plates called tagma Crustacea o Extensive tagmatization o Specialized limbs for different functions  Legs for walking, swimming, defense , mouth o Zooplankton/krill were first legs move in a metachronal wave to swim first group of animals that are the first swimmers, move and affectively trap the algae

Spiralia 

Spiral cleavage

Lophotrochozoa  

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Either the presence of a U shaped gut and lophophore or throchophore larval stage Lophophorates o Lophophore o U-shaped gut: created a u-shaped gut so the anus is located close to the mouth without cross-contamination o Brozoans  Moss organisms  Ciliated tentacles  Traps food and creates a water current, and this filter feeds  Colonial, so they live in groups, share nutrients and things  Has Deutosome characteristics Throchophore larva o Ciliated band: used for swimming and filtering o Undergoes morphogenesis and transforms into 4 different organisms o Symplesiomorphies  Htrochophore  Schizocoel  Dorsal heart and pericardial cavity

Mollusca         

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Radula Dorsal mantle Calcareous spicules or shells Ventral ciliated muscular foot Large diversity and large fossil record Adaptive radiation: has a simple morphology that can be adapted to many different forms o They all share one common origin There are a set of muscles that are able to pull down the shell to let it hide When the shell is down, the mollusc is still able to do all the normal biological acivities Radula o Unique feeding structure that sits on the tongue o On the surface is a set of hardened teeth o Used to grind the surface of inorganic material to scrape off organic material and use it as food Snails (Gastropods) o They are successful because they move up on land o Body is in the shell, able to pull shell over as a protective mechanism o Hermaphrodites 

Every mating event, you end up with 2 fertilized zygotes

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 Sperm transfer comes first, then the egg thing happens after  Seminal receptacle o They have a dart that is trying to stab each other, and the one that is stabbed the deepest is more susceptible to being inseminated Squids and octopods (cephalopods) o Huge fossil record o Has an elongated body o Ammonites  One of the big predators in the Cambrian oceans  Over time, the shell disappears because there are so many more predators from the fresh water (moved into the ocean) and they couldn’t compete  Now squids Clams o Takes the shell and folds it in half o Used cilia on the gill to create water currents to bring in water, and in the water is organic material that is used for food o Clam sits below sentiments with two little openings

Annelida  

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Metamerisim of mesodermal structures o Distinct blocks of muscle Four bundles of setae o When longitudinal muscles contract, the setae stick out and used movement or anchoring Able to burrow by swallowing the material in their way and excreting it out the other end. They also used the materials to harvest organic material Marine worms o Can have jaws, teeth, palps, tentacles, eyes and stuff

Platyzoa  

Loss of coelom Acoelomate or pseudocoelom o Solid mass of tissue, but still have a gut o Circle of muscle on the outside and longitudinal muscle on the outside o Has cilia that allows the organism to move and also have a ”sticky” cells that is used to stick to things o Kept flat by the dorsal ventral o Mouth is located on the ventral (bottom) side in the middle of the body

The cells that are involved breaking down nutrients in the gut were located on the ventral side. Used the stick cells to adhere itself to the substrate and used different cells to break down the food (early Platyhelminthes). o Able to stick and adhere to a surface to be protected from predators o Some flatworms adhere to the surface of coral and secrete a digestive enzymes on the polups. They also found a way to eat the polups and are able to bypass the stinging effects. They coat themselves with the stinging cells of the cnidarian for protection from the cnidaria and other predators Loss of metanephridia, and circulatory system Platyhelminthes o Incomplete gut -> no anus o

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Complex reproductive system associated with hermaphrodism  Testis send the sperm to the sperm duct and is stored in the seminal vesical. When they mate with another organism, and the penis is inserted into the seminal receptacle of the other organism. After mating, the male reproductive system shuts down. Eggs are formed in the ovaries and they travel through the oviduct to the seminal receptacle and are inseminated o Developed a strategy to become smaller and less complex by flattening their body. Surface are is advantageous Life cycle o Invaded the fluid filled body cavities of other organisms (like a parasite) o Can come in 2 different forms: fluke and tape worms  Fluke stick to other organisms (ducts of liver, urinary tract, etc)  When they get in, they stick to the wall, they anneal themselves against the wall to whatever area of the body they are in. They are just a thin little layer, so they do not obstruct the function of the organ that they are in  Larvae are covered in cilia moves around looking for a new host (usually a snail) (miracidium). When finds host, it turns into a sporocyst that produces many redia, which produce cercaria (which looks around for another host). If enters a fish, it lays dormant as metacercaria, and if ingested by an uncooked fish, it will enter the digestive system and start the cycle over again  Very specific to its host and such. Swimmers itch: little bites from the fluke o

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Deuterostomia   

Blastopore becomes the anus Pentaramous symmetry Water vascular system o NOT THE AQUIFEROUS SYSTEM IN SPONGES

The water vascular system is a hydraulic system used by echinoderms, such as sea stars and sea urchins, for locomotion, food and waste transportation, and respiration. The system is composed of canals connecting numerous tube feet. The contraction of the hydrostatic skeleton allows for the movement of the tube feet (has suction cups on the feet) and all are moving in unison. o Predators and carnivores  Can feed on a clam: wraps arms around the clam and uses the feet to open the clam just a little, then turns the stomach inside out, injects it into the clam and secretes digestive enzymes, then uses cilia to bring the food to the body. The clam cannot close because the starfish locks the connective tissue  Can do the same think to coral Mutable connective tissue Endoskeleton o Connective tissue in between the skeleton that can generate movement due to the tissue being connected to the nervous system Starfish and relatives o Thought that the cnidarians and these are related o Looking that the fossils, they appeared to have a body sitting on stocks, with “arms” coming from the top that would push food towards the mouth. Was able to use the nervous system to move the stock (tissues) and able to catch the falling food that is coming down before the animals on the bottom can get it o o

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