zoology

• PHYLUM PORIFERA - [SPONGES]

  1. Earliest multicellular organism linked to descend from a common ancestor along with protists

  2. Do not possess a tissue grade of organization

  3. Organs absent

  4. Marine and a few freshwater

  5. Radial and asymmetrical

  6. No respiratory or excretory system

  7. No nervous system or sense organs

  8. Asexual & Sexual, Regeneration
• PHYLUM PORIFERA - [SPONGES]


  • Body plan: No mouth
  • Water pumped through Ostia - Spongocoel - Out to Osculum
  • Nutrients from water current
• PHYLUM PORIFERA - [SPONGES] Cell types

  • Choanocytes / Collar Flagellated Protist
  • Pinacocytes
  • Porocytes
  • Amoebocytes
  • Spicules - Skeleton surrounded by cells in gelatinous matrix: Calcium carbonate, Silica, Spongin
• PHYLUM PORIFERA - [SPONGES] Feeding and Digestion

  1. All but few sponges are filter feeders

  2. One sponge is a predator

  3. Small number of sponges are parasites
• PHYLUM CTENOPHORA - [COMB JELLY]

  1. Flattened or elongated

  2. All marine, few simple organs

  3. Most spherical and transparent

  4. No bell or polyp shaped as cnidaria

  5. Some are pink, orange, olive, all are bioluminescent

  6. Most are planktonic

  7. No stinging cells; instead have adhesive cells (colloblasts) for food

  8. 8 rows of comb plates of cilia

  9. Origin is obscure
• PHYLUM CTENOPHORA - [COMB JELLY]

  • Body plan: Biradial symmetry
  • Epidermis - Outer / Gastrodermis - Inner [Gelatinous layer of collenchyma]
• PHYLUM CTENOPHORA - [COMB JELLY] Support & Locomotion


  Crawl on bottom! Derived Mesoderm
• PHYLUM CTENOPHORA - [COMB JELLY] Feeding

  1. Most are carnivores

  2. Few are parasitic

  3. Eat small crustaceans/zooplankton

  4. Asexual - Regeneration or fragmentation

  5. Sexual: Both have gender organ, external fertilization
• PHYLUM CYNIDARIA - [JELLY FISH]


  All aquatic, marine & some freshwater
• PHYLUM CYNIDARIA - [JELLY FISH]

  • Body plan/form: Radial/Biradial symmetry
  • Many are polymorphic
  • Polyp (hydroid) and Medusa (jellyfish)
  • Cell tissues: Epidermis diploblastic - Outer, Mesoglea, Gastrodermis
• PHYLUM CYNIDARIA - [JELLY FISH] Movement

  1. Sessile - secretes cup

  2. Hydrostatic Skeleton - flexible by fluid pressure

  3. Mobile - hydrostatic skeleton
• PHYLUM CYNIDARIA - [JELLY FISH] Feeding and Digestion

  1. All carnivores, Cnidocytes, Nematocysts

  2. No respiratory or excretory system

  3. Absorb oxygen from water by way of their skin

  4. Hydra, Blind gut

  5. Lives for 80 years, some jellyfish 10 years
• PHYLUM CYNIDARIA - [JELLY FISH] Reproduction

  1. Asexually, by budding/fusion

  2. Sexually - Most are dioecious
• Feeding and Digestion


  1. All CARNIVORES have Cnidocytes and Nematocysts

  2. Absorb oxygen from water by way of their skin

  3. Hydra has a Blind gut

  4. Some jellyfish live for 80 years, some for 10 years
• Reproduction


  1. Asexually by budding/fusion

  2. Sexually - Most are Dioecious

  3. Most shed gametes into water, often mass spawning

  4. Some can switch genders

  5. Do Wedding Dance
• Chapter 10: Lophotrochozoa
• Characteristics of Phylum Platyhelminthes

  • Simplest phylum at "organ level"
  • Very diverse group including flatworms, flukes, tapeworms
  • Few fossils, no hard parts
  • May be the first animal to have a head & tail and show directed movement
• Body Form of Phylum Platyhelminthes


  • Wide variety of body shapes
  • Bilateral Symmetry
  • Elongated & slender, leaf-like or long & ribbon-like, FLATTENED
  • TRIPLOBLASTIC
• Platyzoa: Phylum Platyhelminthes


  • No synapomorphies
  • Derived tissue - Parenchyma fills spaces between body wall for skeletal support, motility, reserve of regenerative cells
  • First phylum with organ system
  • Unsegmented worms
  • Monoecious with complex reproductive organs
• Body Wall of Phylum Platyhelminthes

  • Epidermis
  • Muscle layers
• Feeding and Digestion of Flatworms

  1. Carnivores mostly free-living forms or endoparasites

  2. Incomplete digestive tract in most, secretes enzymes to partially digest food before "eating" them

  3. Gas exchange through a flattened body wall
• Flatworms were probably the first creatures to have a "brain"
• Some wastes like ammonia are eliminated by diffusion through the body wall
• Class Trematoda


  1. Divided into two subclasses: Aspidogastrea and Digenea

  2. An incomplete digestive tract is present

  3. Most are monoecious

  4. The outer body layer is a tegument
• Subclass Aspidogastrea


  1. Primarily endoparasites of mollusks

  2. The life cycle may involve one host (a mollusk) or two hosts (a fish or turtle)
• Subclass Digenea


  1. Majority of all flukes belong to subclass Digenea

  2. Medically important species

  3. Members have at least two forms and require two hosts: Adult & Larval stages

  4. The eggs hatch in freshwater into a ciliated larva called a Miracidium - penetrates a snail
• Subclass Digenea


  • Majority of all flukes belong to subclass Digenea
  • Medically important species
  • Members have at least two forms and require two hosts: Adult & Larval stages
  • The eggs hatch in freshwater into a ciliated larva called a Miracidium - penetrates a snail and develops into a sporocyst
  • TREMATODE PARASITES of Humans – Chinese liver fluke/ Clonorchis sinesis
• Class Monogenea


  • Monogenetic flukes, Only one generation in their life cycle
  • Mostly ectoparasites of fishes as adults
  • Eggs into ciliated larva attaches to FISH GILLS
• Class Cestoida


  • Cestodes, or tapeworms, are gut parasites of vertebrates
  • NO MOUTH & DIGESTIVE TRACT
  • Absorb nutrients across body wall
  • Consist of a series of repeating units called proglottids
• Subclass Eustoda


  • True tapeworms
• Phylum Gastrotricha


  • Microscopic, aquatic animals
  • Interstitial ocean floor or lake bottom substrate particles
  • Head, neck, trunk
  • Numerous adhesive glands are present
  • Hermaphroditic
• Phylum Micrognathozoa


  • Microscopic, small, jawed animals
  • Two-part head with complex jaw (15 parts)
  • Simple, complete gut
  • NO males
• Phylum Gnathostomulida


  • Jaw worms
  • Slender to thread-like
  • Nervous system with sensory cilia
  • Incomplete digestive tract
  • Use diffusion for circulation, excretion, gas exchange
  • Monoecious
• Phylum Rotifera


  • Abundant in freshwater habitats
  • Corona around their lobes on Heads
• Phylum Ciliophora


  • One of the most recently described phyla
  • Members of this phylum live on the mouthparts of the claw lobster
  • Attach via an adhesive disc on the end of an acellular stalk
  • Very tiny animals
• Phylum Ectoprocta


  • U-shaped
  • Live in sessile colonies of zooids
  • Marine or freshwater environments
  • Colonies produced by asexual budding
  • Sessile in marine & freshwater habitats
• Phylum Brachiopoda


  • Triploblastic, coelomate, bilaterally symmetrical
  • U-shaped gut, NO ANUS
  • Open circulatory system with one or more hearts
  • No gas exchange organs
  • Horse-shoe-shaped lophophore in anterior mantle cavity
• Animal Taxonomy, Phylogeny, and Organization
• Learning Outcome: Section 7.1
• Phylogeny


  A description of the evolutionary history of a group of organisms and is usually depicted using tree diagrams