Invertebrate zoology - Lecture notes unit one PDF

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Invertebrate zoology Chapter 1: intro and environmental considerations 98% are invertebrates 1.3 million out of 1.4 million of animals are invertebrates 36 different phyla 35 are only invertebrates and 1 has some invertebrates animal characteristics:       

Multicellular Eukaryotic Heterotrophic Motile All have sexual reproduction Period of embryonic development cell membrane no cell wall

all animals evolved from protozoans 545 million years ago – Cambrian Explosion= the original evolution of animals and diversification

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Chapter 2; invertebrate classification and relationships Animal classification possibilities 1.

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habitat a. aquatic i. freshwater ii. marine b. terrestrial symmetry a. asymmetric b. radial symmetry c. bilateral symmetry i. cephalization (has a head) embryotic development a. zygote(fertilized egg) 1 cell 2 cells 4 cells 8 cells morula(solid ball of 16-64 cells) blastula (hollow sphere) blastocoel(fluid filled cavity) gastrula (forms embryonic germ layers) b. no germ layers i. no tissue 1. sponges c. diploblastic i. 2 germ layers ii. endo and ectoderm iii. cnidarians d. triploblastic i. 3 germ layers ii. ecto, endo, and mesoderm body plans a. only for triploblastic animals b. acoelomate i. no true body cavity ii. organs embedded in tissue 1. Platyhelminthes c. Pseudocoelomate i. False body cavity not entirely lined by mesoderm 1. Nematodes d. Coelomate i. True body cavity completely lined by mesoderm protostome vs. deuterostome a. Only for coelomate animals b. Protostomes: i. Blastopore develops into the mouth ii. Schizocoelous coelom formation 1. Mesoderm splits to form the coelom iii. Spiral and determinate cleavage 1. Mollusks, annelids, arthropods c. Deuterostomes: i. Blastopore develops into the anus ii. Enterocoelous coelom formation

iii. Folds of mesoderm lining the archenteron rise up and pinch closed iv. Radial and indeterminate cleavage 1. Echinoderms and chordates Phylogeny- evolutionary history of a species or a group of species  

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Stem or root ancestor o Common ancestor to all species in the tree Autopormorphy o Self-derived characteristic o 1st species to have it synapomorphy o shared derived characteristic from a common ancestor symplesiomorphy o shared characteristic not derived from a common ancestor

monophyly- group consisting of a common ancestor and all of its descendants paraphyly- group consisting of an ancestor and a portion of its descendants

CHAPTER 3; the Protists Kingdom Protista: 

1st eukaryote to evolve on the planet o 2.2 billion years ago o unicellular(mostly) o 3 groups  algae  slime molds  protozoans  heterotrophic  motile  no cell walls  ancestors to all animals  complex cell

regulation 

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passive o no energy needed 1. simple diffusion  solute moves from high solute concentration to low 2. osmosis  water moves from low solute to high active o requires ATP 1. active transport  solute against gradient through integral protein 2. exocytosis

 3.  4.  5.  6.  

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solute/ water gets transported out using vesicles o waste removal endocytosis stuff moves into cell using vesicles phagocytosis engulfment pinocytosis intake of water and solute through small indentations on outer membrane of cell that close up receptor mediated traps solutes in receptors o clathrin protein coat

Life cycle of Plasmodium vivax 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

female anopheles mosquito bites and picks up gametocytes gametocytes become gametes in the stomach of the mosquito fertilizationzygotes zygotes into oocysts oocysts undergo meiosis to produce sporozoites sporozoites migrate to the salivary glands of the mosquito mosquito bites and sporozoites enter the body and target liver cells sporozoites undergo asexual reproduction and morph into merozoites merozoites are released into blood and target red blood cells merozoites undergo asexual reproduction and morph into gametocytes

Excavate Protozoans 

flagellated protozoans with a ventral groove for absorption

phylum Parabasala o o o

o o o

multiple flagella undulating membrane parasites and some mutualistic symbionts  Trichomonas vaginalis  Causes trichomoniasis  Parasite to human females  Trichonympha  Lives in a termites stomach to digest cellulose for it  Mastigont systems o Palm-like arrangements of flagella anaerobic nonfunctional mitochondria

Phylum euglenozoa (Euglenophyta)  

Euglenids Euglena gracilis o Bi-flagellated  Only one is locomotory  One is housed in the ventral groove (doesn’t function) o Mixotrophic  Do absorb food but are also photosynthetic  Chlorophyll pigments  Glucose is stored as paramylon o Pyrenoid-inside the chloroplast and synthesizes and stores the paramylon o Photoreceptive eyespot (ocellus) o Pellicle covers the cell  Flexible protein covering

Phylum Kinetoplastida   

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Parasites to vertebrates Have a Kinetoplast o Enormous mass of DNA inside a mitochondrion Aerobic

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Bi-flagellated o One is locomotory and one created an undulating membrane Trypanosoma o Causes sleeping sickness o Lives in bloodstream and strips oxygen from the red blood cells o Changes receptors continuously to evade white blood cells o T. brucei (gambiense)  Causes African sleeping sickness  Tsetse fly = vector o T. cruzi  Causes south American sleeping sickness (Chagas disease)  Vector= kissing or assassin bug  Leishmania o leishmoniasis o found in the middle east o vector= sand fly  (no-see-um)

amoebozoan protozoans  

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amoeba like cells with pseudopodia ectoplasm and endoplasm o ecto- thick and near the surface (protects from rupture) o endo-thin and internal phagocytosis- ingest food by engulfment

phylum Gymnamoeba   

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free-living and shelled amoebas has lobopodia- thick and blunt pseudopodia Amoeba proteus o Large nucleus Arcella vulgaris o Shelled amoeba

Phylum foraminifera   

Forams (common name) Shell like cellular covering- called a test o Made up of calcium carbonate ( CaCO3) Reticulopodia- Thin needle-like branching pseudopodia o Extends out of the pores of the test

Phylum Radiolaria     

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Radiolarians Internal skeleton- endoskeleton o Made up of Silica or strontium sulfate Intracapsular zone o Endoplasm Extracapsular zone o Ectoplasm Axopodia or filopodia –thin needle like

Phylum heliozoan 

Actinosphaerium o Axopodia or filopodia o Medulla  Internal region containing endoplasm o Cortex  Outermost region containing ectoplasm

Phylum choanoflagellida   

Choanoflagellate Protists Closest living ancestors to animals Choanocytes o Flagellated cells with a mucus covered collar  Covered collar traps food o

CHAPTER 4; the Poriferans and Placozoans Kingdom Animalia Phylum Porifera –sponges         

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Pore barring Filter feeding Asymmetrical or radially symmetrical Sponges are parazoans o Early branch off animal tree No gastrula o No germ layers and therefore no tissues Sessile= attached Moves during larval stage Cell specialization level of organization o Many different independent cell types Cell types o Pinacocytes  Flat scale-like cells covering the outer surface  Hexagon shaped o Porocytes  Tubular cells surrounding the ostia (incurrent pores)  Regulates water influx  Contain actin to contract and open the cell o Choanocytes  Food trapping cells  Line a spongocoel or some smaller cavity o Archeocytes

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Many different types All sit in the mesohyle- thick gelatinous fluid in the body of a sponge  Water and collagen protein  Totipent- serve as stem cells  TYPES:  Amoebocytes o Moves via pseudopodia through the mesohyle o Receives food from the choanocytes and digest it o Contains lysosomes o Distribute nutrients to other cells  Sclerocytes o Produce spicules of CaCO3  Spongocytes o Produce spicules of spongin  Protein and silica  Lophocytes/ collenocytes o Produce and secret collagen into the mesohyl Myocytes  Contain actin to contract  Surround the osculum –excurrent pore Reproductive cells  Sit in the mesohyl  Produce gametes through meiosis

Sponge body plans 

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Asconoid o Less than 2% of sponge species o Simples vase shaped o 1-4 cm in height o CaCO3 spicules o Water enters through ostia into incurrent canals o Water collects in the spongocoel  Lined with choanocytes o Water exits out the osculum Syconoid o Larger than Asconoid o 3-8cm in height o vase shaped with a folded outer wall o spicules of CaCO3 o water enters through numerous ostia into incurrent canals o water moves to radial canals  lined with choanocytes o water moves to the spongocoel and out the osculum Leuconoid o 90% of all sponges o typically have spongin spicules o asymmetrical o water enters through ostia into branching incurrent canals o incurrent canals lead to flagellated chambers lined with choanocytes

o

water moves excurrent canals and out the oscula

sponge reproduction 

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asexual o fragmentation  occurs in favorable conditions  accidental  parent undergoes regeneration o internal budding  occurs in harsh conditions  gemmules= internal, resistant buds  develop along the spongocoel, radial canals, or flagellated chambers  package of Archeocytes  pg 84 fig 4.3  micropyle- opening of a gemmule  gemmule germination influenced by temperature but not oxygen concentration sexual o sponges are hermaphrodites o testes  groups of cells that produce sperm through meiosis o ovaries  groups of cells that produce ova through meiosis o both sit in the mesohyl o sperm is released out the oscula o self-incompatibility- they reject their own sperm o sperm enters into a second sponge through the ostia o internal fertilization o internal development o takes place in the mesohyle o zygote2 cells 4 cells8 cellsmorulablastula  stereoblastula  solid mass of cells  coeloblastula  hollow sphere of cells o larval stage- amphiblastula larva (fig 4.10)  has flagellated and non-flagellated cells  motile – allows for dispersal  parenchymella larva- flagella elongate only in Leuconoid

phylum Placozoa     

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1 species Trichoplax adhaerans Only found in shallow sea water or in salt water aquariums Looks like a multicellular amoeboid colony o Cells covering the body have flagella No tissues

CHAPTER 5; intro to the hydrostatic skeleton Water providing structure to the animal body 

Seen in cnidarians and ctenophores

Phylum Cnidaria    

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2.

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Cnid= nettle Approx. 50,000 species Radially symmetrical throughout their entire lives Diploblastic  2 germ layers  ecto and endoderm incomplete gut  one opening serving as mouth and anus tissues level of organization epidermis a. single cell layer body covering (fig 6.4) i. epithelio- muscle cells 1. simple cuboidal epithelial cells 2. contain actin ii. cnidocytes 1. stinging cells 2. covering the tentacles 3. pic on phone also pg 103 fig 6.1 4. cnidocil- trigger of the cnidocytes a. operculum opens to release the nematocyst once triggered b. nematocyst- stinging apparatus with neurotoxins that could paralyze prey 5. mesoglea a. thick gelatinous fluid b. water and collagen gastrodermis a. digestive tissue lining the gut i. coelenteron b. extra cellular digestion c. from endoderm i. gland cells 1. produce and secrete digestive enzymes into the coelenteron ii. nutrient cells 1. absorb digested nutrients iii. substitute cells 1. totipotent 2. become other cell types iv. nervous tissue 1. from ectoderm 2. nerve net 3. made of sensory cells 4.

CHAPTER 6; the Cnidarians CHAPTER 7; the Ctenophores CHAPTER 8; the Platyhelminthes CHAPTER 10; the Gnathifera: Rotifers, Acanthocephalans, and Two Smaller groups CHAPTER 11; the Nemertines CHAPTER 12; the Molluscs CHAPTER 13; the Annelids CHAPTER 14; the Arthropods CHAPTER 16; the Nematodes CHAPTER 19; the “Lophophorates” (Phoronids, Brachiopods, Bryozoans) and Entoprocts CHAPTER 20; echinoderms

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