Systems Table:

System

Protist

a

Porifer

a

Cnidari

a/  

Ctenap

ohra

Platyhel

menthes

Mollusca

Annelida

Digestio n/  

Feeding

intrace

llular  

digesti

on,  

diffusio n  

across  

membr ane,  

phagoc ytosis

Filter

feedin

g;  

intrace llular  

digesti

on

Nemat

ocyts  

and  

tentacl

es to  

captur

e prey,  Gastro

dermal

gland  

(extrac

ellular  

digesti

on);  

collobl

ats,  

comple te  

digesti

on  

(cteno

phora)

mouth,  

pharynx, intestine ,  

intracell

ular and  extracell ular  

digestio

n

Intracellu lar and  

extracell

ular;  

mouth,  

radula,  

stomach, intestine

s, anus,  

complete

Same  

mollusca  as  

complete ; crop  

and  

gizzard.

Nervous

n/a

N/A

Nerve  

net  

with  

proton

eurons; sensiti

ve to  

touch;  

equilibr ium in  

ctenop

hora

Sensory, motor,  

associati on  

neurons; centraliz ed  

ventrally with  

brain;  

light,  

tachtile,  chemore ception

Same as  Platyhel

minethes ; vision  

and  

equiliriu

m

Same as  mollusca; add  

periphrea l nerves

How do protists acquire food?

Don't forget about the age old question of What is the definition of constant return scale?

Locomo

tion/  

Muscles

cilia,  

flagella ,  

pseudo podia

flagell

ated  

sperm, sessile

adult,  

flagell

ated  

cells  

with  

microv

illi fror  feedin

g;  

pianoc

ytes  

midly  

contra

ctile

Polyps  

may  

glide,  

medus

a  

plankto nic,  

floating ,  

swimm

ing  

with  

hydrost atic  

skeleto

n;  

Ctenop

hora -  

comb  

rows

Ciliated  

cells on  

ventral  

side;  

adhesive glands;  

longitudi nal,  

circular,  and  

oplique  

muscles

head

food  

region;  

hydraulic skeleton; siphon to intake an expell  

water  

(aquatic)

longitudi

nal and  

circular  

muscles,  setae

Circulat

ory

n/a

N/A

N/A

N/A

open

open

Osmore

gulation

diffusio n  

across  

membr ane,

diffusi

on  

thru  

cells  

and  

out of  

body

Diffusio n into  

gastrov ascular cavity  

and  

out of  

body

flame  

cells -  

protonep heridia

1-2  

metanep heridia;  

empties  into  

mantle  

cavity  

then  

diffusion  out of  

body

metanep

heridia

Excretio n

Diffusi

on  

across  

membr ane

cellula

r level  

-  

diffusi

on  

throug

h cells  and  

out of  

body  

mass

Diffusio n into  

gastrov asular  

cavity  

and  

out of  

body  

mass

flame  

cells -  

protonep heridia;  

diffusion through  body  

wall

1-2  

metanep heridia;  

empties  into  

mantle  

cavity  

then  

diffusion  out of  

body

metanep

heridia

How do porifera acquire food?

We also discuss several other topics like Caste system continued by the mauryan enhanced with stricter boundaries by the?

Skeletal /Form

Contai

ned  

within  

cell  

membr ae or  

wall;  

hydros

tatic  

skeleto n

Asym

metric

al or  

symm

etrical; Spongi

n or  

spicule s  

made  

of  

silica  

or  

calciu

m  

carbon ate or

Radial  

symme try;  

hydrost atic  

skeleto

n,  

diplopl

astic,  

mesogl

ea;  

acoelo

mate

Bilateral  symmetr y;  

Epidermi s and  

Mesoder m  

(muscles );  

acoelom ate

Bilateral  Symmetr y, mantle that  

secretes  calcareo

us shell  

(in  

most);  

coelomat e

coelom;  

bilateral  

symmetr

y, worm

like;  

pseudoco elomate;  metameri c body;  

hydrostat ic  

skeleton

Integum ent

N/A

N/A

N/A

Epidermi s and  

Mesoder m

Epidermi s

epidermis with  

setae

Respirat ory

gas  

exchan ge/  

diffusio n  

across  

membr ane;  

photos

yntheis or  

cellular respira

tion

diffusi

on  

betwe

en  

cells

diffusio n  

betwee n cells

Diffusion between cells into and out  

of body

diffusion  through  

mantle;  

some  

with gills

not yet  

discussed

How do mollusca acquire food?

If you want to learn more check out What is the redox reactions?

Characteristics by Phyla:

Porifera: Sponges 

∙ Asymmetrical or Symmetrical body plan

∙ 3 types of cells, but no tissue

∙ Central cavity or branching cavity with ostia and oscula for filter feeding Cnidaria 

∙ Radial Symmetry

∙ Mesoglea

∙ Cnidocytes

Ctenophora 

∙ Gelatinous mesoglea

∙ Eight rows of ciliary bands (comb rows)We also discuss several other topics like What is climacteric respiration?

∙ Have colloblasts

Acoelomate 

∙ None discussed in class.  

Platyhelminthes 

∙ Worm-like with bilateral symmetry

∙ Incomplete guy, usually

∙ Not segmented, except tapeworms

Rotifera 

∙ Anterior end with corona

∙ Mostly planktonic in marine environment

Mollusca 

∙ Two-part body

∙ Mantle that secretes a calcareous shell (in most), covers visceral mass ∙ Mantle cavity

Annelida 

∙ Metameric body

∙ Paired epidermal setae

Notable Classes by Phyla with Common Names Porifera: Sponges 

∙ Calcarea  

o Synapomorphy = spicules made of calcium

o All 3 canal systems (Asconoid, Synconoid, and Leuconoid) o Marine

∙ Demosongiae  

o Synapomorphy = spicules of silica or spongin

o Lauconoid canal system

o One freshwater family; includes marine bath sponges

∙ Hexactinellida  

o Synapomorphy = 6-rayed spicules made of silica We also discuss several other topics like What is menthyl chloride?

o All marine, deep water

o Synconoid or leuconoid canal system

Cnidaria 

∙ Anthozoa – Sea Anemone, Coral

o Synapomorphy – gastrodermis with septa; cnidocytes

∙ Scyphozoa – True Jellyfish

o Synapomorphy – cnidocytes on gastrodermis and epidermis ∙ Cubozoa – Box Jellies

o Synapomorphy – cuboidal body shape Don't forget about the age old question of Can learning theory help with interventions for children with welfare or behavior issues?

∙ Hydrozoa – Hydra

o Synapomorphy – cnidocytes on epidermis only

Ctenophora 

∙ Nuda  

o Synapomorphy – without tentacles

∙ Tentaculata

o Synapomorphy – with tentacles  

Acoelomate

∙ No classes to know

Platyhelminthes 

∙ Turbellaria – Flatworms

o Synapomorphy – free-living with digestive tract

∙ Trematoda – Flukes

o Synapomorphy – life cycle requires multiple hosts

∙ Monogenea – Monogenetic Flukes

o Synapomorphy – one life cycles in one host

∙ Cestoidea – Tapeworms  

o Synapomorphy – lack a digestive tract

Rotifera 

∙ No classes to know

Mollusca 

∙ Polyplacophora – Chitons

o Synapomorphy – mantle with single calcareous plate

∙ Cephalopoda – Octopus, Squid, Cuttlefish, Nautilus

o Synapomorphy – tentacles modified from foot

∙ Bivalvia – Clams, Mussels, Oysters, Scallops

o Synapomorphy – two calcareous valves contain visceral mass

∙ Gastropoda – Snails, Slugs, Conches, Limpets

o Synapomorphy – torsion: u-shaped digestive tract

Annelida 

∙ Polychaeta – Clam Worm; Marine Worms

o Synapomorphy – not discussed in class yet

∙ Ogliochaeta – Earthworms

o Synapomorphy – not discussed in class yet

∙ Hirudinea – Leeches

o Synapomorphy – not discussed in class yet

Structure/Function:

Porifera: Sponges 

∙ Pinocytes Cells 

o Compose cuticle, mildly contractile, minor tactile function  

∙ Choanocytes Cells 

o Flagellated cells with microvilli – create water current and filter feed ∙ Mesenchyme Cells 

o Secrete skeletal elements

o Maintain structure and form

o Intracellular digestion, transport and storage of food.  

∙ Spicules – structure/support, defense

∙ Spongin – structure/support

∙ Canal Systems – water flow, filter feeding.  

Cnidaria 

∙ Feeding and digestion: 

o Cnidocytes – defense, feeding, attachment

o Nematocysts – cells which contain cnidocytes; entangle and paralyze prey o Gasrodermal gland – secretes mucus and enzymes for extracellular digestion

o Tentacles – capture prey; move prey to mouth

∙ Reproductive 

o Alternative polyp and medusa stages (in most)

∙ Locomotion 

o Polyps – usually sessile but may glide through nematocysts and hydrostatic  skeleton

o Medusa – planktonic; may swim or float

 Swim = vertical movement

 Float = horizontal movement

 Weak swimmers

o Longitudinal and circular muscle fibers

∙ Nervous System 

o Neurons diffused throughout body in a net-like fashion

o Allow tactical function

Ctenophora 

∙ Comb rows – locomotion

∙ Colloblasts – capturing prey

∙ Complete gastrovascular cavity; branched - digestion

Acoelomate 

∙ None discussed

Platyhelminthes 

∙ Parasitic (many)  

∙ Body form: 

o Epidermis – ciliated on ventral side for movement

 Adhesive glands to stick to substrate/rocks

o Mesoderm – contain muscle tissues for movement

 Longitudinal, circular, oblique muscles

∙ Digestion: 

o Mouth, pharynx, intestine.  

o Intracellular and extracellular digestion

o Biotic digestion with bacteria and absorption within intestines

∙ Excretion and Osmoregulation: 

o Flame cells for osmoregulation  

o Excretion through diffusion through the body wall

∙ Nervous System: 

o Brain, transverse and lateral nerve cords

o 3 neurons which work together  

 Sensory – detect external and internal environments

 Motor – movement and locomotion

 Association – memory  

o Ocelli – light detection and photoreception

o Chemoreception

Rotifera 

∙ Corona at anterior end – feeding and movement

Mollusca 

∙ Mantle Cavity – excretion, gas exchange, digestion

∙ Integument: 

o Epidermis – usually ciliated, protection of the body,

∙ Digestion: 

o Radula – scrape, drill; mechanical breakdown of food

o Stomach – chemical digestion and some absorption (ex. Of water) o Intestines – biological digestion/breakdown, absorption

∙ Circulatory: 

o Open circulatory system

o Acts as hydraulic/hydrostatic skeleton

∙ Respiratory: 

o Diffusion through mantle

o Some with gills

∙ Excretion and osmoregulation: 

o One or two metanephridia, empty into mantle cavity

 Primarily osmoregulation

o Diffusion out of mantle

∙ Nervous system: 

o Ventrally located

o 3 neurons, central nervous system with brain

o Sensory organs for touch, smell, taste, equilibrium, and vision

Annelida 

∙ Setae – movement, digging, holding in burrows

 ∙    Muscular system 

o Circular muscles thin and lengthen

o Longitudinal muscles shorten and fatten

∙ Digestive system

o Crop – storage sac located below the pharynx

o Gizzard – used for grinding up food and soil to feed

 ∙    Excretory System 

o Pair of metanephridia – osmoregulation and some excretion

Questions:

What are the 3 canal systems in sponges in order from least complex to most  complex? 

∙ Asconoid (simplest), Syconoid, Leuconoid (most complex)

Wy are medusa stages utilized to disperse young? 

∙ Bet-hedging strategy to get young farther away from the sessile adults Why does Cestoidea (tapeworms) lack a digestive tract? 

∙ Selection away from it

What are the three neurons, and their functions, present in Platyhelminthes  and all later lineages? 

∙ Association – memory and learning

∙ Motor – movement/locomotion

∙ Sensory – detection of internal and external environments

 Explain the life cycle of Centrocestus formosanus. 

∙ Life cycle takes place over multiple hosts (3)

∙ Begins in definitive host where reproductive stage occurs; young released through  feces of hose

∙ Miracidium (ciliated larva) develop from egg and find intermediate host

∙ Miracidium reproduce asexually inside intermediate host to form either a sporocyst or redia, which release cercaria into the water

∙ Cercariae find a fish host and encyst (usually on gills) and form a metacercaria ∙ Definitive hose eats fish and gets infected, starting the life cycle again What makes Cephalopoda effective predators? 

∙ Large brains, tearing mouthparts, rapid locomotion

What type of digestion occurs in the following areas: mouth/mouth area,  stomach, intestines? 

∙ Mouth/mouth area – mechanical breakdown

∙ Stomach – chemical

∙ Intestines - biotic

What is the reference point for ventrally or dorsally located systems? ∙ The digestive tract

What are the primary and secondary functions of our kidneys? ∙ Primary – osmoregulation

∙ Secondary – excretion  

What are some of the important roles Annelida plays? 

∙ Food chain, medical uses, soil decomposition

Vocabulary:

Radial Symmetry – symmetry about a point; in more than one plane Bilateral Symmetry – symmetry about one plane

Intracellular digestion – digestion within a cell, such as by chemical process Extracellular digestion – digestion outside of the cell, such as chewing, tearing, biotic  breakdown by bacteria

Mesoglea – gelatinous material between the gastrodermis and epidermis; acts as a  hydrostatic skeleton

Cnidocytes – cells which contain the nematocysts; used for defense, feeding, and  attachment; some deliver  

toxins

Nematocysts – the “stinger” or barb which sticks into the prey

Cnidocil – trigger located on the cnidocyte which activated the nematocyst; everts by  osmotic pressure  

Polyp – the sessile life stage. May be as an individual or in a colony

Medusa – planktonic life stage

Tactile Function – sensitivity to touch

Statocyst – detection of balance; Ctenophora

Comb Rows – 8 rows of ciliated bands used for locomotion and filter feeding Colloblasts – adhesive cells on tentacles of Ctenophora used to capture prey Septa – divisions within the body cavity; may be the start to developing coelom in later  lineages

Osmoregulation – regulation of water content

Excretion – removal of nitrogenous waste

Brain – enlarged area of nerves on the anterior end

Ocelli – photoreceptor/light detection

Endoparasite – internal parasite which resides in the body and uptakes nutrients from the host

Ectoparasite – external parasite which feeds on blood and tissues

Mantle cavity – area between the mantle and visceral mass; many function; significance  – jet propulsion,  

torsion in snails

Mantle – covers the visceral mass; secretes a calcareous shell in most Radula – tongue-like organ used for scrapping and drilling

Torsion – twisting of the digestive tract to result in a u-like shape

Meatamerism – segmented arrangement of the internal and external body Segmentation – division of the body into a series of repeated identical segments  Hydrostatic skeleton – a support system which relies on water pressure to maintain  structure

Hydraulic skeleton – a hydrostatic skeleton which aids in locomotion Longitudinal Muscles – muscles with run from the anterior to posterior end  Circular Muscles – muscles which circle the body from dorsal to ventral side Oblique Muscles – muscles found in Platyhelminthes which run diagonally on the body Setae – small extensions on the body made of chitin used for locomotion, digging, and  holding  

in burrows

Crop – a storage sac located anterior to the gizzard

Gizzard – part of the digestive system used for grinding to aid in mechanical digestion Tagmatization – forming of body region; found in insects and humans

Cladogram:

∙ A cladogram was presented in class. Please review the lineages. ∙ This cladogram will cover everything from the previous cladogram with expansions to Porifera, Cnidaria, Ctenaphora, a single lineage for Acoelomates, and the  Protostomes.  

∙ The expansion to the protostomes is only within Lophotrochozoa with the following  classes expansions: platyhelminths, Rotifera, Lophophorata, Mollusca, Annelida.  The important classes for each are noted above.  

∙ After the expansions, a single lineage for Deuterostomes may be presented to  show a complete linage of eukaryotes.

References: