Phylum Mollusks

Question 1

What is adaptive radiation

Answer 1

used to describe the evolution of many new species from a common ancestor

Question 2

Is this phylum very large or very small?

Answer 2

very large

Question 3

How many species of fossil mollusks

Answer 3

over 60,000 (second only to foraminifera)

Question 4

what type of symmetry is in this phylum

Answer 4

bilateral, some with a secondary derived asymmetry

Question 5

what three body features are found in all molluscs

Answer 5

muscular “foot”
visceral mass (contain internal organ)
mantle (secrete calcium carbonate shell)

Question 6

what is HAM

Answer 6

Hypothetical ancestral mollusk

Question 7

what is HAM body plan

Answer 7

simple snail like body covered by a cap-like limpet shell
digestive and respiratory tract travels from front to back, gills and anus in back

Question 8

Are most diecious or monoecies?

Answer 8

Most dioecious
some monoecious (garden snail)

Question 9

what type of development (direct and indirect) is found in mollusks

Answer 9

cephalopods and some other mollusks have direct development
remaining have indirect development (planktonic trochophore larval stage emerges from egg)

Question 10

trochophore larvae is found in which other phyla

Answer 10

some Annelida, Platyhelminthes

Question 11

in general, what type of nervous system is present

Answer 11

several ganglia

Question 12

what are cephalopods known for?

Answer 12

most advanced of any invertebrate

Question 13

cephalization in this phylum

Answer 13

cephalopods (active predators)
gastropods (snails)
most others (think clam) are grazers, scavengers, or filter feeders

Question 14

Explain excretory system in molluscs

Answer 14

have well developed system with two nephridia

Question 15

what are nephridia

Answer 15

like kidneys

Question 16

what are circulatory system in mollusks

Answer 16

open system with pumping heart, blood vessels, and blood sinuses whereby blood returns to the heart
cephalopods have a closed system

Question 17

respiratory system

Answer 17

most have gills derived from mantle tissue for gas exchange

Question 18

how do bivalves work in respiratory system

Answer 18

incurrent and excurrent siphons in bivalves

Question 19

classes of mollusks

Answer 19

–Caudofoveata
–Aplacophora
–Polyplacophora
–Monoplacophora
–Gastropoda
–Cephlapoda
–Rostroconchia
–Bivalvia
–Scaphopoda

Question 20

Class monopacophora

Answer 20

found on ocean bottom
exhibit psuedosegmentation

Question 21

class polyplacophora aka

Answer 21

chitons

Question 22

how many dorsal plates do polyplacophora have

Answer 22

8

Question 23

where are polyplacophora found and how do they eat

Answer 23

found in intertidal zone of seacoast; feed by grazing on algae on rocks by magnetite radula (teeth)

Question 24

class scaphopoda

Answer 24

bury in sediments look like bananas

Question 25

what animals are in bivalvia class

Answer 25

clam
oyster
mussels
limpets
periwinkles
scallops

Question 26

explain Bivalvia general anatomy

Answer 26

two shells connected by hinge ligament dorsally
shell grows outward in rings from the umbo
food extends anteriorly from shell to pull animal forward
adductor muscles

Question 27

Bivalvia respiration

Answer 27

gills
incurrent and excurrent siphons

Question 28

Bivalvia digestive anatomy

Answer 28

gills are used for filter feeding
mucus on gills trap food particles

Question 29

where are freshwater bivalve eggs fertilized?

Answer 29

internally, in super branchial chamber above gills

Question 30

what do egg of freshwater bivalve develop into

Answer 30

glochidia larva

Question 31

is marine bivalve fertilization external or internal?

Answer 31

external

Question 32

how are bivalves endangered

Answer 32

dams prevent fish migration, so some cant reproduce bc their fish host are not present
water pollution
introduced mussels taking over

Question 33

what are invasive introduced bivalves in our region

Answer 33

zebra mussel
asian clam

Question 34

what is symbiotic relationship in clams?

Answer 34

mantel tissue contain photosynthetic zooxanthellae which provide nutrients for clam

Question 35

class gastopoda whats special about it

Answer 35

molluscan class is largest in terms of recognized species
ONLY terrestrial molluscs

Question 36

what is gastropoda radula

Answer 36

rasping/scraping organ in mouth

Question 37

gastropods reproduction

Answer 37

most are monoecious
sperm exchanged- dont self fertilize
some use a dart to puncture mate
development is indirect
eggs laid singly or attached to substrate as a jelly mass

Question 38

gastropod diversity (nudibranchs)

Answer 38

nudibranchs- marine gastropods feed on cnidarians
larva have shells- lose it during development
papillae covering dorsal surfaces contain reused nematocysts

Question 39

gastropod diversity (sea hare)

Answer 39

marine which squirts a purple secretion from purple gland in their mantal cavity when provoked

Question 40

gastropod diversity (conus)

Answer 40

cone shell- marine
stings its prey to paralyze
can kill other cone shell or even human

Question 41

class Cephalopoda general characteristics

Answer 41

ancient
all are active predators

Question 42

what animals are in Cephalopoda class

Answer 42

squid
octopus
nautilus
cuttlefishes

Question 43

how are cephalopod advanced (10)

Answer 43

well-developed external cephalization and foot modified into a series of tenacles with suckers
closed circulatory system
have large brain
sophicated sensory organs
chemosensory cells
use bioluminescence for camouflage and communication
complex communication
sophisticated behaviors

Question 44

how do cephalopod reproduce?

Answer 44

courtship behavior
sperm encased in spermatophores
one modified tentacle used to pluck a spermatophore from own mantle cavity and insert it into mantle cavity of a female

Question 45

what animal makes peals

Answer 45

oysters

Question 46

dioecious def

Answer 46

having male and female parts in separate animals

Question 47

monoecious def

Answer 47

having male and female parts in same animal