mollusks bivalves:gastro
DESCRIPTION
TRANSCRIPT
![Page 1: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/1.jpg)
Phylum Mollusca
Class: Gastropoda
Class: Bivalvia
![Page 2: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/2.jpg)
Characteristics of Mollusca
• Protosome characteristics
• Coelom surrounds heart
• Open circulatory system (except cephalopods)
![Page 3: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/3.jpg)
Class Gastropoda
Snails, Limpets and Slugs
![Page 4: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/4.jpg)
Gastropoda• Planning on being rich and
famous?• Wining and dining at the
most expensive restaurants?
• Romantic trips to Paris? • Ever wonder what Ceaser
munched on after long hard days ruling the roman empire?
• Than you should be familiar with ESCARGOT!!!!
![Page 5: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/5.jpg)
General Body Plan: Gastropod
• 1. Head foot• Head: sensory nerves,
mouth – Anterior: near the
head/mouth
• Foot: attachment and locomotion – Posterior: near the anus– Flattened w Cilia:
locomotion
![Page 6: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/6.jpg)
That slimy foot… • Snail Slime:
– Suction power: travel up and down trees
– Escape: Emit a nasty tasting slime when threatened
– Movement: Allows them to easily squeeze through tight spaces
– Water Retention
• How Ms. Cota looks so young: – Skin regenerating – used in skin beauty products
![Page 7: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/7.jpg)
General Body Plan: Gastropod
• 2. Visceral Mass– Organs of
digestion – Circulation – Reproduction – Excretion – Dorsal to the
head foot
![Page 8: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/8.jpg)
General Body Plan: Gastropod
• Mantle (shell) – Attached to visceral
mass• Encloses most of the
body
– Protection
• Mantle Cavity: – Gas exchange– Elimination of digestive
wastes – Release of reproductive
products
![Page 9: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/9.jpg)
Respiration
• One Gill in mantle cavity – Oxygen is taken in – Diffused through the cells
• Open Circulatory System – Pushes blood in to
expand– Pulls it out to contract
![Page 10: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/10.jpg)
General Body Plan: Mollusca
• Radula: Scraping mouth – Chitinous belt & curved
teeth • Covers fleshy tongue • Muscles move it back
and forth • Conveyor belt
• Digestion – Scrape algae– Enzymes break down
food in stomach
![Page 11: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/11.jpg)
CFU
• How do mollusks exchange gasses – Filter air through their gills
• Where are these gills located?– The mantel
• What is the structure called that scrapes up food?– A Radula
• All mollusks have: – A visceral Mass – A head foot – A mantel
![Page 12: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/12.jpg)
Gastropoda
• Marine, Freshwater, Terrestrial
• Signifying feature: Torsion
![Page 13: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/13.jpg)
Tosion
• Benefits – Head enters first:
protection – Operculum seals
opening to prevent drying out
– Allows clean water to enter mantle cavity
– Makes snail more sensitive to stimuli coming from the front
![Page 14: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/14.jpg)
Torsion
![Page 15: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/15.jpg)
Reproduction
• Monoecious: can be whatever sex they want! – Internal cross
fertilization – One snail acts as
female one acts as male
– Deposit eggs in gelationous strings
![Page 16: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/16.jpg)
CFU
• What is Torsion?– The 180 degree twisting of internal organs
in snails
• How is Torsion adaptive? – Pulls head in first, seals opening, locates
all sensory nerves in the front
![Page 17: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/17.jpg)
Class Bivalvia
Clams, Oysters, Mussles, Scallops
![Page 18: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/18.jpg)
Bivalvia!
• Edible• Commercial value:
Form Pearls • Valuable in removing
bacteria from polluted water! – Rely on water currents to
get food – Filter in nutrients, filter out
clean water
• Valuable food source: humans, raccoons, otters, birds
![Page 19: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/19.jpg)
Structure
• Two halves of a shell: Valves – Adductor muscles hold
valves shut
• Visceral Mass• Mantel Cavity• Gills • Cilia• Siphon:
– filters water in and out of shell
![Page 20: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/20.jpg)
Foot
• Most mollusks have foot that can be used differently – Attach mollusk to
surface – Act as a lure to
attract prey – Surround organs for
safety
![Page 21: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/21.jpg)
Respiratory System
• Respiration: Cilia in gills move water into mantel cavity – Water tubes
exchange water to blood through diffusion
– Water exits bivalve
![Page 22: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/22.jpg)
Digestive System
• Food comes in through gills – Sorted – Digested – Waste forcibly
pushed out of mantel cavity by valves shutting quickly
![Page 23: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/23.jpg)
Human Interaction
• Many, many mollusks are threatened or endangered– Over harvesting– Pollution– Loss of habitat – Loss of water
currents
![Page 24: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/24.jpg)
CFU • What is the technical term for the two halves of the
shell?– Valves
• What structure filters water in and out of the shell – Siphon
• What is the function of the foot – Attach mollusk to substrate, act as lure
• Why are bivalves important to humans?– Pearls, food source, pollution filter
• How are humans affecting bivalves? – Over harvesting, pollution, loss of current
![Page 25: Mollusks bivalves:gastro](https://reader033.vdocuments.pub/reader033/viewer/2022061115/5462debcaf79597c138b4c29/html5/thumbnails/25.jpg)
Get ready for dissecfrtion!