Bio Lab 4 (Mollusca)

Question 1

phylums that are being studied

Answer 1

Mollusca and phylum annelida

Question 2

coelomate

Answer 2

both mollusks and annelids have a circular body cavity called a coelom. mesoderm is in two places, see diagram

Question 3

coelomates are divided into

Answer 3

protostomes (GI tract develops mouth first then anus) and deuterostomes (GI develops anus first then mouth)

Question 4

protostomes

Answer 4

include phylum molusca, annelida and arthropoda

Have well developed nervous, circulatory, excretory reproductive and digestive systems

Question 5

deuterostome

Answer 5

include echinodermata (starfish), and vertebrates (hemichordate and chordata)

Question 6

mollusca

Answer 6

• mantle that secretes a calcium shell
• Their coelom is often just a small chamber surrounding the heart
• Open circulatory system
• Body plan: includes a visceral mass of organs, a muscular foot used for locomotion, a calcium shell, and a mantle that secretes the shell (may aid in respiration),
• Have unique rasping tongues called radula
• cephalization (has a head)

Question 7

Annelida

Answer 7

• Coelomates
• very serially segmented into repetitive segments but has parts of system in each (not yet fully developed) divided by a septa!
  -Complete digestive tract
  Have bristles called setae on each segment that help with crawling
  -closed circulatory system
• has cephalization

Question 8

Mollusca are

Answer 8

mollusks

Question 9

annelida are

Answer 9

segmented worms

Question 10

Class Polyplacophora

Answer 10

• commonly called chitons
• has 8 shell plates (poly) on the dorsal
• have a little segmentation

-radula, a horny-toothed organ in the mouth, scrapes food (algae) from rocks.
Mollusca

Question 11

class gastropoda

Answer 11

gastropods (gastro = stomach, poda = foot) (snails, nudibranchs and slugs)
- different species have different
shells
- have a radula and a spiral shell due to unequal growth rate in snails but no shell in nudibranchs and slugs
Mollusca

Question 12

class bivalvia

Answer 12

Clams, oysters, scallops, and mussels are bivalves (bi = two, valve = door or shell) having a dorsally hinged shell in two parts

• filter water
• held together by adductor muscles and an umbo (elbow)
• are filter feeders
• have a foot that has more organs inside and is used for locomotion/ anchoring
• Mollusca

Question 13

Class Cephalopoda

Answer 13

• Head-foot, cuttle fish, squid, and octopus
• Lack a radula, but have a parrot-like beak for tearing flesh
• Siphons used for respiration and jet propulsion, free-swimming
• Foot modified into tentacles,
• the nautilus shell iS NOT A GRSTROPOD
  closed circulatory system
• cephalized and segmented (septa divide)
• some segments are specialized, and each one has brittles called setae

Mollusca

Question 14

Class Polychaeta

Answer 14

poly = many, chaeta = setae) filled with poison
- very segmented
- have fleshy appendages called parapodia
These appendages help in filter feeding, locomotion, reproduction, holding and capturing prey

Question 15

Class Oligochaeta

Answer 15

EARTHWORM

• have a lip called the prostomium
• first body segment is called the peristomium
• closed circulatory system
• ventral spinal chord
• clitellum is closer to the head than the anus
• few setae
• have a GI system, brain
• have a nephridium for getting rid of wastes

Question 16

Class Hirudinea

Answer 16

leeches. Leeches lack setae

• Carnivores and blood sucker
• Three slicing teeth
• Salivary gland is anti-coagulant
• release packets of sperm called spermatophores into female

Question 17

IN LAB,

Answer 17

dissected earthworms and clam

Question 18

cephalization

Answer 18

formation of a head that has the sense organs. usually in the front of the body

Question 19

mantle secretes the

Answer 19

shell for protection

Question 20

mollusks that don’t have shell

Answer 20

octopus, slug and one more

Question 21

deuterostomes

Answer 21

GI tract develops anus to mouth

Question 22

protostomes

Answer 22

develop GI from mouth to anus

Question 23

Gastropoda animals

Answer 23

snails, nudibranchs and slugs

Question 24

how do bivalves filter water

Answer 24

Trap food particles in gills and water moves into the shell via incurrent siphon and out of the shell via excurrent siphon

Question 25

how does bivalve open and close

Answer 25

Powerful “adductor” muscles close the shell, (“add” the two shells together)
Hinge and umbo cause the shells to open when the adductor muscles relax

Question 26

cephalopod skeleton

Answer 26

Circular and longitudinal muscles work against a fluid filled coelom acting as an hydrostatic skeleton.

Question 27

what do Polychaeta’s parapodia help with?

Answer 27

filter feeding, locomotion, reproduction, holding/capturing prey

Question 28

how do oligocaheta get rid of waste

Answer 28

Paired nephridia for fillration pulling in body through a nephrostome and wastes out a nephridiopore

Question 29

good folding for increase in SA?

Answer 29

typhlosole arising from the dorsal wall of an oligochaete. doubles the SA

Question 30

muscles in a earthworm vs. nematode

Answer 30

earthworm has circular and longitudinal muscles

Question 31

dorsal vs ventral cross section of earthworm

Answer 31

• dorsal has the typhlosole, the nephridia open out of the ventral side. also ventral nerve chord

Question 32

body shape of leeches vs oligochaete and polychaete?

Answer 32

dorsoventrally flattened vs others

Question 33

leeches have setae?

Answer 33

no

Question 34

are leeches as segmented as others?

Answer 34

no

Question 35

what function do suckers serve other than feed on leech?

Answer 35

locomotion