34
1 Dissection of the Clam Venus mercenaria copyright cmassengale
| Date post: | 14-Dec-2015 |
| Category: |
Documents |
| Upload: | kelsi-carp |
| View: | 218 times |
| Download: | 1 times |
1
Dissection of the Clam
Venus mercenaria
copyright cmassengale
2
copyright cmassengale
3
Taxonomy of Bivalve Taxonomy of Bivalve MollusksMollusks
KingdomPhylumClassGenus Species
•Animalia•Mollusca•Bivalvia•Venus•mercenaria
copyright cmassengale
4
Bivalve MollusksBivalve Mollusks
•Soft bodies invertebrates•Have a muscular foot that
can be extended for movement
•Two part, hinged shell•Complete, one-way
digestive tract with a mouth & anus
•Separate sexescopyright cmassengale
5
Bivalve MollusksBivalve Mollusks• No eyes or distinct
head• Have siphons to
circulate water through their bodies
• Filter feed on plankton
• Mussels are large and have a flat, more oblong shell shape, while freshwater clams are smaller (3/4 inch) and typically more round copyright cmassengale
6
Indirect DevelopmentIndirect Development• Goes
through a free-swimming, larval stage called the trochophore
• Adults move slowly by their extendable foot
copyright cmassengale
7
Bivalve MollusksBivalve Mollusks• Protostomes – blastopore
becomes the mouth• Have a fully lined body or
mantle cavity• Body organs called visceral
mass protected by mantle which secretes the shell
• Open circulation• Most are sessile or sedentary• Includes clams, oysters,
scallops, & musselscopyright cmassengale
8
BivalvesBivalves
copyright cmassengale
9copyright cmassengale
10
External AnatomyExternal Anatomy
copyright cmassengale
11
Bivalve ShellBivalve Shell• Umbo is the raised, oldest part of the
shell and is used to find surfaces
Dorsal
Ventral
Anterior
Posterior
UMBO
copyright cmassengale
12
Bivalve ShellBivalve Shell• Shell show regular spacing of external growth rings
on shells and their progressive crowding as the animals grow older
Growth Rings
copyright cmassengale
13
Bivalve ShellBivalve Shell• Bivalves have an incurrent and excurrent siphon to bring
in water containing food & O2 and for excess water & wastes to leave
Siphons
copyright cmassengale
14copyright cmassengale
15
•The hinge ligament holds the two halves of the shell together
Bivalve ShellBivalve Shell
copyright cmassengale
16
Internal AnatomyInternal Anatomy
copyright cmassengale
17
Scissor tips or a screwdriver & can be used to open the shell
copyright cmassengale
18
Adductor MusclesAdductor Muscles
Strong adductor muscles help open & close the valves and must be cut to examine the interior of the clam
copyright cmassengale
19copyright cmassengale
20
Inside Shell Lining
•The inside of the shell is pearly and smooth to protect the body
•Oysters coat irritants with a substance called “mother of pearl”
copyright cmassengale
21copyright cmassengale
22
Teeth located on the dorsal edge of the shell lock to keep shells from sliding
copyright cmassengale
23
The mantle makes a CaCO3 (limestone) shellcopyright cmassengale
24
Mantle cavity
Gills hang outside visceral mass (body) in the mantle cavity & remove O2 as H2O flows over them
Gills
copyright cmassengale
25copyright cmassengale
26copyright cmassengale
27copyright cmassengale
28
Water FlowWater Flow• Incurrent siphons aid in bringing in
water with food and oxygen• Cilia direct water into the gills, while
labial palps direct water into the mouth
Cilia on the gills pulls in water
move food toward the mouth
copyright cmassengale
29
VISCERAL MASS -contains respiratory, digestive, & reproductive
systems
copyright cmassengale
30
HEART & PERICARDIAL CAVITY
copyright cmassengale
31
Nervous SystemNervous System
•Consists of 3 pairs of ganglia (brain)
•Has 2 pairs of nerve cords extending from this
copyright cmassengale
32
•Nitrogen waste from kidney• Digestive waste from anus• Sperm or egg (if external fertilization) • Larva (if internal fertilization)
Released into Mantle Cavity to be Released into Mantle Cavity to be removed by excurrent Siphon:removed by excurrent Siphon:
copyright cmassengale
33copyright cmassengale
34copyright cmassengale
![[PPT]Clam Dissection · Web viewDissection of the Clam Venus mercenaria * copyright cmassengale * * * * * * copyright cmassengale Resource * * * * * * * * * * * * * * * * * * * * *](https://static.documents.pub/doc/80x56/5aa6232f7f8b9a7c1a8e5555/pptclam-dissection-viewdissection-of-the-clam-venus-mercenaria-copyright-cmassengale.jpg)
