Biology II Lab Midterm Study Guide Highlighting Things that Spears emphasized and we MUST know Underlining Gastrulation Diagram on the very last page referred to frequently throughout this study guide Good Luck Studying key vocabulary terms Phylum Porifera pore bearers aka SPONGES Features Classification based on spicule morphology 1 Hexactinellida comonly known as glass sponges that produce 6 sided silicious spicules Don t have distinct cells The cell layers are syncytial cell bodies are fused to gether into a mass of many nuclei Syconoid or leuconoid in form 2 Demospongiae produce silicious spicules and spongin 80 of sponge population Mostly Marine and leuconoid in form 3 Calcarea calcium carbonate spicules All species are marine Includes all three sponge architectures asconoid syconoid and leuconoid Embryonic Development no embryonic germ layers Symmetry Assymetrical Skeleton Support spicules spongin collagen Organization Cellular no true tissues Movement Locomotion None sessile attached to substrate Digestion intracellular Sensory Nervous No specialized structures Feeding suspension filter feeders choanocytes have a collar of microvilli that trap food particles from flowing water that get phagocytized engulfed by the cell passes on to archaeocytes aka amoebocytes Excretory Osmoregulation simple diffusion Circulation Simple diffusion no specialized structures Respiration simple diffusion Reproduction Asexual Regeneration external budding fragmentation gemmules Gemmules are a densed hardened ball of archaeocytes in the mesohyl that s protected by collagen and spicules Gemmules are usually found in freshwater sponges If the sponge experiences a harsh winter and dies the parent sponge will disintegrate and the gemmule will resume growth in the spring and will be a clone of its parent Sexually Broadcast spawning released sperm enter another sponge where they are captured phagocytized by choanocytes which lose their flagella and collar become amoeboid and travel through the sponge mesohyl to fertilize egg cells The fertilized egg develops into a simple parenchymula or amphiblastula larva a ball of cells with flagella on the outside the larva exits the parent sponge swims for a few hours then settles and develops into a new sponge Sponge Life Cycle page 3 of Lab Manual Mostly monoecious makes eggs and sperm They reproduce both sexually and asexually Anatomy of a sponge The outer layer of sponges is called the pinacoderm The cells of the pinacoderm are called pinacocytes Within the pinacoderm are porocytes which are cells that have a pore to allow for the passage of water into the sponges interior Porocytes can contract to regulate water flow The incurrent pores of the sponge wall are ostia Sponges interior cavity is called the spongocoel aka Atrium A constant flow of water into the spongocoel is created by choanocytes Choanocytes are cells with beating flagella that produce current Choanocytes also have a collar of microvilli that traps food particles from in flowing water Once water passes into the spongocoel it is expelled through the osculum a very large opening Beneath the pinacoderm is a gelatinous matrix called mesohyl Spicules and spongin fibers which are used for skeletal support are found within the mesohyl Spongin are a type of collagen protein Archaeocytes are also found in the mesohyl Archaeocytes aka amebocytes amoebocytes are totipotent cells that can differentiate into any other type of sponge cell They can even develop into eggs or sperm Archaeocytes ingest and digest food transferred from choanocytes through phagocytosis Archaeocytes also transport nutrients to other cells Archaeocytes can also differentiate into sclerocytes that can secrete sponging Archeocytes aslo differentiate into spongocytes that secret spongin Three Types of Sponge Architecture Body Plans Asconoid Simplest o Water flow Ostia spongocoel osculum Syconoid has increased surface area for filter feeding by folding Sycanoids use flagellated radial canals instead of flagellated atriums spongocoels o Water flow Ostia incurrent canal prosopyle radial canal apopyle spongocoel osculum o Leuconoid Most Complex greater increase in surface area than sycanoids Leuconoids use flagellated chambers instead of radial canals These chambers are more efficient water pumping systems Leuconoids often lose a distinct spongocoel and use multiple oscula o Water flow Ostia incurrent canal prosopyle radial canal flagellated chamber apopyle spongocoel osculum See our lab manual page 2 for more labeled structures Quick notes Sponges are the simplest multicellular heterotrophs hence animals Ecological Roles o Dominant structural elements in marinescapes o Important for water filtration o Influence water chemistry o Provide refuge for other animals Leuconoid Ascanoid usually are very tiny Phyla Radiata Cnidaria Ctenophora Phylum Cnidaria bearing stingers hydroids jellyfish sea anemones and corals Features Classification phase 1 Class Hydrozoa Hydroids Clearly visible polyp phase mostly colonia Not easily seen medusa 2 Class Scyphozoa Jelly fish not easily seen polyp phase very small vey noticible medusa phase ofter large medusa phase 3 Class Staurozoa solitary polyp phase No medusa phase 4 Class Anthozoa very obvious polyp phase No medusa phase Subphylum Zoantharia Hexacorallia sea anemones and hard corals Subphylum Alycoonaria Octocorallia soft corals sea fans sea pens pansies Subphylum Ceriantipatharia tube anemones thorny black corals 5 Class Cubozoa Box Jelly fish unknown poly phase Predominantly medusa phase Organization tissue level Embryonic Development Diploblastic two germ layers goes through gastrulation and stops at step A go to the very last page to see a diagram of the steps of gastrulation Therefore cnidarians have incomplete guts with one Gastrovascular Cavity GVC serving as an anus and a mouth Symmetry Radial to protect itself from all directions because they don t have eyes Skeleton Support hydrostatic skeleton fluid filled GVC Movement Locomotion slow swimming or sessile attached to a substrate Sensory Nervous nerve net rhopalia small sensory structures that usually control muscle contraction and the speed of swimming see pic below they are glowing statocystys used for balance and sensing gravity and ocelli used for photoreception Feeding Mostly carnivorous and capture prey with tentacles Excretory Osmoregulation simple diffusion Circulation food canals only in schyphozoan medusae Digestion Extracellular
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