Exam 2 Reading Notes

glochidia

'arrow-head'

prostomia

'before mouth'

umbo

'shield boss'

mesogastropods

- includes marine, freshwater & terrestrial i.e.: periwinkles, turrets, vermetid worm-like tube snails, horn shells, slipper limpets, moon snails, cowries

neogastropods

- marine only i.e.: whelks, harp shells, miters, olive shells, cone snails, tulip shells, dove shells

archaeogastropods

- most marine - most herbivores i.e.: abalone, true limpets, trochids, turbans, keyhole limpets

Class Bivalvia characteristics

1. laterally compressed body 2. 2 hinged shells

Class Scaphopoda characteristics

1. long adhesive tentacles called captacula with which they search & grab food 2. tusk-shaped shell, open at both ends

Class Cephalopoda characteristics

1. protective cranium 2. siphon & tentacles/arms are the modified foot 3. shell reduced or absent 4. close circulatory system

Phylum Mollusca, Class Gastropoda characteristics

1. torsion 2. an operculum

Consider for a moment why broadcast spawning is only effective in water environments. Also consider the purpose of a trochophore larvae and what is being gained/lost by the oligochaetes not having that stage of development. Log your thoughts here.

Broadcast spawning is effective in water environments because organisms can release gametes that can travel faster than them with the help of water currents. Trochophore larva are free-swimming, this stage may be missed in oligochaetes because their develop takes place in a cocoon and are not free-swimming.

T or F: A protandric organism is first female, then male. This is an example of a sequential hermaphrodite.

FALSE

T or F: Just as in other molluscs, the cephalopod circulatory system is open.

FALSE

T or F: Oligochaetes do not have any setae (bristles).

FALSE

T or F: You can tell that an animal is an echiuran because of the fully retractable action of it's anterior end

FALSE

T or F: The umbo and hinge mark the dorsal region of the bivalve.

TRUE

Diagram the oligochaete circulatory system as a flow chart.

The oligochaete circulatory system is closed: The 5 hearts pump blood into the main ventral vessel and flows posteriorly then comes back anteriorly through the dorsal vessel.

annelida

anulus: little ring eidos: shape 'ringed forms'

archaeogastropoda

archaeo: old gastropoda: snails

In a gastropod with full torsion, the placement of the mantle cavity & ctenidia is: a. posterior, dorsal to the foot b. anterior, dorsal to the cephalon c. lateral, up in the spiraling visceral mass of the shell d. ventral & posterior

b. anterior, dorsal to the cephalon

bivalve

bi: two valve: shells

ganglion

brain

infauna

burrow, live within the substrate

Which of these summarizes a differences between polyplacophorans & gastropods? a. 1 has calcareous hard parts, the other does not b. 1 has a radula, the other does not c. 1 has a single pair of ctenidia, the other has multiple pairs d. 1 has a ventral foot, the other does not

c. 1 has a single pair of ctenidia, the other has multiple pairs

Which of the following bivalve structures is NOT involved with feeding? a. labial palps b. ctenidia c. pericardium d. incurrent siphon

c. pericardium

Which of the following statements about echiurans is incorrect? a. there are no persistent reproductive structures b. they have a few pairs of chitinous setae c. the gut is U-shaped d. there is a single coelomic space, no septa

c. the gut is U-shaped

cephalopods

cephalo: head pod: foot

pallial vessels

circulatory system

Coleoidea

coleo: sheath oidea: like

The [fill in the blank] helps prevent dessication in terrestrial oligochaetes.

cuticle

Which of the following is NOT a difference between sipunculans and echiurans? a. one has a posterior anus and the other has a lateral anus b. one has setae and the other does not c. one has anterior tentacles and the other does not d. one has spiral cleavage and the other has radical cleavage

d. one has spiral cleavage and the other has radical cleavage

echiurans (Class Polychaeta)

echis: viper ura: tail 'serpent like' aka - spoon worms

hirudineads

ectoparasitic segmented worms

'True' segmentation, also known as [fill in the blank], seems to have been lost in these spoon worm polychaetes.

eusegmentation

oligochaetes

few bristled segmented worms

pygidium

final segment of a polychaete larva

labial palps

fleshy protrusions near the mouth

Zoologists use the term urogenital duct to refer to an opening where both wastes (urine) and [fill in the blank] are released.

gametes

In sipunculans, [fill in the blank] occurs across all epidermal tissues.

gas exchange

Polychaete parapodia function in both locomotion and [fill in the blank].

gas exchange

The ventral groove on the echiuran proboscis is also called the:

gutter

operculum

hardened structure on foot (shield)

metamerism

having parts

cephalon

head (Greek)

hectocotylus

hecto: hundred cotylus: hollow thing

clearing of turbidity

helps sequester toxins, impact microbial food chain, changes light penetration onto the benthos

Heterodonta

hetero: different donta: teeth i.e.: surf clams, heart shells, cockles, giant clams, razor clams, zebra mussels, quahogs, geoduck, shipworms, piddocks, vesicomyids

homonomous

homo: same

If an organism shows [fill in the blank], then it has repeated segments that are mostly equal in size & shape.

homonomous metamerism

Polychaetes are efficient burrowers because of their [fill in the blank] skeleton.

hydrostatic

lamellibranch

lamelli: thin plate branch: gill

peritoneum

lining of the coelomic cavities

siphuncle

living tissue

opisthobranchs

mainly marine gastropods with shells absent or reduced - detorsion

polychaetes

many bristled segmented worms

mesogastropods

meso: middle

The words segmentation and [fill in the blank] are basically interchangeable.

metamerism

metatroch

middle 'wheel' or ciliary band on a trochophore larva

nemertea

named after Greek sea nymph Nemertes 'ribbon' or 'boot lace' worms

Nautiloidea

nautilus: sailor oidea: like *carry their own ship

neogastropoda

neo: new

nephrostomes

nephro: kidney stome: mouth

circumbuccal ring

nervous system

nudibranch

nudi: naked branch: gill

Octopoda

octo: 8 poda: feet

Class Oligochaetes

oligo: few chaeta: bristles clitellata

Leeches, unlike other annelids, has an [fill in the blank] circulatory system.

open

Paleoheterodonta

paleo: old hetero: different donta: teeth freshwater, larval stage is fish parasite

parapodia

para: beside podia: feet - fleshy out-pockets of body wall function: locomotion & gas exchange

Class Polychaetes

poly: many chaetae: bristles - mostly marine

hirudin

prevents blood coagulation at site of feeding

prostomium

pro: before stomium: mouth

prosobranchs: shelled aquatic snails

proso: front branchia: gills

Protobranchia

proto: first branchia: gill i.e.: nuculids, solemyids

bioturbation

provides oxygen, releases nutrients

Pteriomorphia

pterio: wing/feather morphia: shape i.e.: mussles, oysters, scallops, jingle shells

ovotestis

reproductive system

ctenidia

respiratory system

rhynchocoel

rhynco: snout coel: cavity

Scaphopoda

scapho: spade poda: footed

annelids

segmented worms

Sepioidea

sepia - cuttlefish

prosobranchs

shelled aquatic gastropods - full torsion

sipuncula

siphunculus: little tube aka - peanut worms

Two of the five bivalve subclasses have the root 'donta' in their names. This translates to [fill in the blank].

teeth

A peanut worm's [fill in the blank] inflate due to fluid pressure controlled by the contraction of compensatory sacs.

tentacles

pulmonates

terrestrial gastropods - lung like cavity that opens to environment through pneumostome

atoke

the anterior portion of a reproducing polychaete

epitoke

the swimming sexual portion of a reproducing polychaete

byssal threads

thick hair-like threads

The term [fill in the blank] means having three tissue layers.

triploblastic

annelids

triploblastic eucoelomate segmented vermiform protostomes

eusegmentation

true segmentation

torsion

twisting of visceral mass & nervous system

hinge

where the 2 valves come together