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8/14/2019 Lecture 14, Ch. 33
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Lecture #14 Date _____
s Chapter 33 ~
Invertebrates
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Parazoa
s Invertebrates: animals
without backbones
s Closest lineage to
protists
s Loose federation of
cells (unspecialized);
no tissuess Phy.:Porifera
(sponges)
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Phylum:Porifera(pore bearer)
s Sessile (attached to bottom)
s Spongocoel (central cavity)
s Osculum (large opening)
s Choanocytes (flagellated collar cells)s Hermaphroditic (produce both sperm and eggs)
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The Radiata, I
s Diploblastic
s Radial symmetry
s Phy: Cnidaria (hydra, jellies,
sea anemones, corals)
s No mesoderm; GVC
gastrovascular cavity (sac with
a central digestive cavity)
s Hydrostatic skeleton (fluid held
under pressure)
s Polyps and medusa
s Cnidocytes (cells used for
defense and prey capture)
s Nematocysts (stinging capsule)
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The Radiata, II
s Phy: Ctenophora (comb
jellies)
s 8 rows of comblike plates
of fused cilia (largestanimals that use cilia for
locomotion)
s Tentacles with colloblasts
(adhesive structures thatcapture prey)
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Eumetazoa: The Acoelomates
s Phy:Platyhelminthes(flatworms, flukes, tapeworms)
s Bilateral; no body cavity
s Predators, scavengers,
parasites
s Triplobastic; mesoderm but,
GVC with only one opening
s Some cephalization
s Many pathogens
(Schistosoma, Cestodidias)
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Eumetazoa: Pseudocoelomates, I
s Body cavity partially
derived from
mesodermally derived
tissue
s Phy:Rotifera
s 1st with a complete
digestive tract
s Hydrostatic skeleton
s Parthenogenesis: type of
reproduction in which
females produce offspring
from unfertilized eggs
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Eumetazoa: Pseudocoelomates, II
s Phy:Nematoda(roundworms)s Very widespread group of
animals (900,000 sp. ?)
s Cuticle (tough exoskeleton)
s Decomposition and nutrient
cycling
s
Complete digestive track; nocirculatory system
s Trichinella spiralis
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The Coelomates: Protostomes, I
s Phylogenetics debated.
s Phy:Nemertea (proboscis and
ribbon worms)
s Complete digestion and closed
circulatory system (blood)
s Phy: the lophophorates (sea
mats, tube worms, lamp shells)
s Lophophore: Circular shaped
body fold with ciliated tentacles
around the mouth
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The Coelomates: Protostomes, II
s Phy: Mollusca (snails, slugs,
squid, octopus, clams, oysters,
chiton)
s Soft body protected by a hard
shell of calcium carbonates Foot (movement), visceral mass
(internal organs); mantle
(secretes shell); radula (rasp-
like scraping organ)
s Ciliated trochophore larvae(related toAnnelida?)
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The Coelomates: Protostomes, III
s Phy: Annelida (earthworms,
leeches, marine worms)
s True body segmentation
(specialization of body regions)
s Closed circulatory system
s Metanephridia: excretory tubes
s Brainlike cerebral ganglia
s Hermaphrodites, but cross-fertilize
QuickTime and aCinepak decompressor
are needed to see this picture.
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The Coelomates: Protostomes, IV
s Phy:Arthropoda trilobites
(extinct); crustaceans (crabs,
lobsters, shrimps); spiders,
scorpions, ticks (arachnids);
insects (entomology)s 2 out of every 3 organisms
(most successful of all phyla)
s Segmentation, hard exoskeleton
(cuticle)~ molting, jointed
appendages; open circulatorysystem (hemolymph); extensive
cephalization
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Insect characteristics
s Outnumber all other forms of life
combined
s Malpighian tubules: outpocketings
of the digestive tract (excretion)
s
Tracheal system: branched tubesthat infiltrate the body (gas
exchange)
s Metamorphosis...
s incomplete: young resemble
adults, then molt into adulthood
(grasshoppers)
s complete: larval stages (looks
different than adult); larva to adult
through pupal stage
QuickTime and aCinepak decompressor
are needed to see this picture.
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The Coelomates: Deuterostomes, I
s Phy:Echinodermata (sea stars, sea
urchins, sand dollars, sea lilies, sea
cucumbers, sea daisies)
s Spiny skin; sessile or slow moving
s
Often pentaradials Water vascular system by hydraulic
canals (tube feet)
QuickTime and aCinepak decompressor
are needed to see this picture.