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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

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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

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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)

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