Chapter 31: Sponges, Cnidarians, Ctenophores, and Protosomes

You have a sample of cat emesis (vomit) and find worms in the sample. The cylindrical worms are long and slender, pointed at each ends, with no other distinguishing characteristics. You conclude they are member of which phylum?

A.) Platyhelminthes

B.) Nematoda

C.) Cnidaria

D.) Annelida

E.) Nemertea

B.) Nematoda

What specialized structure do crustaceans use to sense gravity?

A.) antenna

B.) statocyst

C.) radula

D.) parapodium

E.) scolex

B.) statocyst

Cnidocyte Structure (3)

-Nematocyst: fluid filled organelles, thread extends when discharged

-Operculum: cover(lid)

-Cnidocil: trigger

Cnidarians are….

diploblastic, radial symmetry, two body forms (poly and medusa)

Cnidarian Featrues (4)

-gastrovascular Cavity: digestive cavity (one opening)

-mesoglea: jelly-like layer between endoderm and ectoderm

-nerve net: movement

-hydrostatic skeleton: movement (fluid filled)

Cnidarian classes

-hydrozoa: polyps

-scyphozoa: jellyfish

-anthozoa: flower animals (corals, anemones)

-cubozoa: box jellyfish

Ancestral Features of Lophotrochozoans

-multicellula, triploblastic, bilateral symmetry, protostomic

Phyla: platyhelminthes, mollusca, and annelida

Characteristic of Phylum Platyhelminthes

Class turbellaria

-acoleomate, unsegmented flatworms

-organ level (none for circulation or gas exchange, some for sense)

-simple nervous system (brain and nerve chords)

-gastrovascular cavity (digestion)

Four classes of Phylum Platyhelminthes

-turbellari: flatworms

Parasitic:

-trematoda: flukes

-monogenea: flukes

-cestoda: tapeworms

Class Cestoda Features

-parasitic faltworms, segmented flatworms (internal parasites of vertebrates)

-anterior end modified into hold-fast, lost digestive cavity, lost sense organs,

Molluscan features

-soft body, head, foot, coelom, circulation (open and closed), radula (tongue with chitinous teeth), complete digestive system

Phylum Mollusca Classes (3)

Gastropoda, Bivalvia, Cephalopoda

Class Gastropoda Features

(snails, slugs, conchs, sea slugs)

- cephalic: defined head

-chitin acts as file, depend on orientation (back and forth or drill)

-pulminate lungs'

-right and left handed coil shells→adaptation→ snake only eats one

Class Bivalvia features

(clams, oysters, mussels, scallops)

-two halves connected by hinge

-no head (asiphalic)

-heart, kidney, etc

-foot

Class Cephalopoda features

(octopus, squid, nautilus, cuttlefish)

-cephalic

-well developed head

-water in cyphon, into mantle cavity, coools cyphon

-loose skin: pigment can be concentrated or dispursed in cells=range of colors

Phylum Annelida features

(polychaeta, oligochaeta, hirudinea)

-segmented

-septa (internal membranous partitions)

-annuli (surface rings)

-nervous system, circulatory, digestive

-respiration across body surface

ceolomate

Class Polychaeta Features

blue crawl leg

-marine

-cephalic

-setae (multiple)

-jaws with pedipalps

-eyes, antennae, sensor tentacle, parapodia

Class Oligochaeta

earthworm

-all 3 habitat

-proteins, lipids, mucus (moisture)

-acephalic

-no jaws

-filter feeder

-no eyes, antennae, tentacles, or parapodia

-clitellum: undergoes reproduction, mucus, allows for exchange of sperm cells

Class Hirudinea features

leeches

-parasites

-annuli (surface rings)

-setae or appendages: none

-suckers: muscular structure at both ends

Clade Ecdysozoa features

-polyphyletic

-molting

-multicellular, triploblastic, protostomic development

Phylas of Ecdysozoa

nematoda and arthropoda

Phylum nematoda features

(Ascaris, hookworms, pinworms, trichin worm)

-elongated and round

-pseudocoelomate

-no annuli or setae

-hydrostatic skeleton

-eutely: fixed number of cells

-dioecious: separate sexes

-sexually dimorphic

phylum Arthropoda features

most succesful group

-coelomate

-segmented

-paired, jointed-may functions

-protein outer layer (waxes protect again moisure)

-Chitin and protein inner layer

-senses: antennae and compound eyes

-gills or trachael tubes

-book lungs

Subphylum Chelicerata features

-adapted fangs or pinchers

-pedipalps second pair of appendages

-cephalothorax abdomen

Chelicerata Suphylum classes

-Merostoma: horsehoes crabs

-Arachnida: spiders, scorpions, ticks, daddy long legs

4 pairs of legs

Subphylum Crustacea

(crayfish, lobsters, crabs, shrimp, barnacles)

-mandibles and maxillae

-nonbranched antennae

-branched

2 pairs antennae (taste and touch)

-cephalothorax and abdomen

-dioecious and sexually dimorphic

-compound eyes

-antennal glands

Hexapoda Class Insecta features

-head, thorax, abdomen

-uniramous appendages (3 pairs of legs)

-wings (one or two pairs)

-1 pair antennae

-eye spots

-mandibles and maxillae( chewing, piercing, lapping labial parts)