Porifera
Phylum
Cnidaria
Platyhelminthes
Nematoda
Common Name
“Pore bearer”
“Stinging Celled”
“Flatworms”
“Roundworms”
Representative(s)
sponges
jellyfish, sea anemone,
hydra
planarian, tapeworm, fluke
Ascaris, Trichinella,
hookworm, pinworm
Habitat
mostly marine, aquatic
mostly marine, aquatic
planarian - pond bottom
tapeworm - parasitic
parasitic, aquatic, terrestrial
(complex cycle)
Body Plan (symmetry, #
germ layers, body cavity)
asymmetric
2 germ layers(no mesoderm)
acoelomate
radial
2 germ layers
acoelomate
bilateral
3 germ layers ***1st!
acoelomate
(1st mesoderm so 1st tissues)
bilateral
3 germ layers
**pseudocoelomate (only!)
Food Getting and Digestion
“filter feeders” - food with
water in incurrent pores, out
excurrent pore (osculum)
collar cells -draw water/food
in, amebocytes -carry food to
other cells (ameboid mvmt)
sting / paralyze prey using
nematocysts on tentacles,
then bring food into mouth
with tentacles
planarian - extends mouth +
pharynx like vacuum on
pond bottom; 1 anterior + 2
posterior intestines
tapeworm - hooks + suckers
to attach to host
**1st to have mouth and anus
so “tube within tube”
Circulation (open/closed,
imp details)
diffusion
diffusion
diffusion
diffusion, smaller vessels
Nervous System
none really
“nerve net” reflex response
to touch, chemicals
***1st ~ cephalization
Planarian: Primitive brain +
longitudinal, transverse nerve
cords; eyespots, auricles
(“smell”)
Tapeworm: reduced
reduced in parasitic forms
since environment is constant
Reproduction
Asexual ~ budding
Sexual - hermaphroditic,
external fertilization
Asexual ~ budding
Sexual - egg + sperm,
larva, goes thru both body
forms in process
Asexual ~ fragmentation
Sexual - hermaphroditic,
planarians - cross fertilize
tapeworm - self fertilize
Complex life cycles
male and female worms
Respiration
diffusion
diffusion
diffusion
diffusion
Movement
sessile
polyp: mainly sessile but
1) glides on base
2) somersaults
3) flips onto tentacles
nerves + muscles control
mvmt in planarian
some free living, some
parasitic (depends on stage)
Phylum
Annelida
Mollusca
Arthropoda
Echinodermata
Common Name
“segmented worms”
“mollusks”
“jointed feet”
“spiny skinned”
Representative(s)
Class Oligochaeta - earthworm
Class Polychaeta - sandworm
Class Hirudinea - leech
Chitons
Class Gastropoda - snail, slug
Class Bivalvia - clam, oyster
Class Cephalopoda -octopus,
squid, nautilus
Subphyla:
Trilobitomorpha - extinct
Chelicerata - spider (Arachnida)
Crustacea - lobster, crab
Uniramia - insect (Insecta)
centi + millipede (Myriapoda)
starfish (sea star)
sea urchin
sea cucumber
sand dollar
Habitat
terrestrial, aquatic, parasitic
mostly marine (not slug etc)
terrestrial, aquatic....anywhere!
Mostly marine
Body Plan (symmetry, # germ
layers, body cavity)
bilateral
3 germ layers
coelomate (**1st true coelom)
bilateral
3 germ layers
coelomate
bilateral
3 germ layers
coelomate
radial
3 germ layers
coelomate
Food Getting and Digestion
earthworm: mouth - pharynx - buccal
cavity - esophagus - crop - gizzard intestine - anus
leeches: external parasites - sucker like
mouth to hold on, hirudin prevents
blood clots...
Bivalve (clam): “filter feeder” - in
with water thru incurrent siphon caught in mucus on gills - mouth.....
Cephalopod: hunts prey; uses
tentacles, puts in mouth
mouth, appendages, and eating habits
adapted for many diff environments +
food sources
water vascular system (sieve
plate + ring, radial canals + tube
feet) used to pry open mollusks
(bivalves) - extends stomach out
mouth into it!
Circulation (open/closed, imp
details)
closed circulatory system
aortic arches, dorsal + ventral blood
vessels
bivalve (clam): open - blood in
sinuses bathe tissues
cephalopods: closed - (need more
O2 since more active)
open circulatory system (sinuses)
open circulatory system
Nervous System
suprapharyngeal ganglion (“brain”) +
ventral nerve cord, ganglia in each
segment...
Bivalves: primitive brain, receptors
Cephalopods: complex brain,
strategy! Open jars, mazes
brain, ventral nerve cord, ganglia,
tympanum, complex or simple eyes,
antennae
basic - ring + radial nerves
Reproduction
hermaphroditic - cross fertilize (adv can mate with any other earthworm!) ;
clitellum secretes cocoon over (see
parts)
male and female
internal fertilization
bivalve: sperm in incurrent siphon
of female; dev outside
cephalopod: squid die after
octopus female guards cave
male + female
internal fertilization
1) some just grow up
2) some must molt
3) some undergo metamorphosis
- remember diff b/w lobster?
Male + female
external fertilization
bilateral larva settles + devs into
radial adult form
Respiration
diffusion thru moist skin
gills
gills (lobster), booklungs (spider),
tracheal system with spiracles
(grasshopper)
diffusion across skin gills
Movement
earthworm: front setae dig in, pull
back end along; hind setae dig in, push
fwd
sandworm: side feet for swimming
(parapodia)
clams: extend foot in sand, fills with
blood like anchor, pulls rest twd
foot; scallops: open + close
cephalopods: jet of water +
tentacles
variety: walking legs, swimmerets,
wings, ...
Watervascular system (canals +
tube feet)
Excretion
nephridia in ea segment put liquid
waste out sides “kidney”
Malphigian tubules - put liquid wastes
into hindgut + out