Phylum Mollusca Flashcards
What are Molluscs?
They are 🐌 snail, claim, octopus 🐙.
They are coelomate animals.
Mollusca have what around the coelom?
They have mesenteries around the coelom.
Another structure of Animals in phylum mollusca?
They are protostomes animal.
They are spiral 🌀 cleavage.
True Organ system.
They have gas exchange through Brody surface, gills or lungs 🫁.
Equated molluscs and molluscs on land?
Equation molluscs have gills
Land molluscs have lungs.
What system do molluscs have?
Molluscs have open circulatory system,
But cephalopoda have close circulatory system.
Close circulatory system have?
Capillaries ➡️ and cells of the body are surrounded by Capillaries.
Blood 🩸 flows with a fast speed ➡️ blood 🩸 is not direct contact with tissues.
Vertebrates have closed circulatory system. (Cephalopoda)
Open circulatory system?
Blood flow with a low speed.
Blood is in the direct contact with the tissue of the body.
Blood 🩸 is not confined to blood vessels.
Arthropods and Molluscs.
Cephalopods are what?
They are largest invertebrates on land.
Do molluscs have eyes?
Yes, and they can form images.
Why molluscs had common ancestors?
Annelids and molluscs had a common ancestor, because of coelom and larva stage.
Do molluscs have metamerism?
No, they are not divided by body parts, like Annelids, chordata or arthropods.
Molluscs are not metameric.
What does adaptive radiation ☢️ mean in mollusks 🦑 ?
It means they had a common ancestor before, but the evolved and went to different environments and they became successful, and started living in those environments.
So, basically it means they came from common ancestor.
Largest animal kingdom?
Arthropods ➡️ Molluscs ➡️ Nematodes ➡️ Ctenophora.
Who moved to shallow water?
Only bivalves and Gastropoda moved to shallow water 💦 and fresh 💧.
Who are the most intelligent invertebrates?
Phylum cephalopods are the most intelligent.
How is coelom of mollusks 🦑?
Coelom is limited to heart, some gonads and part of kidney.
How does the body of molluscs look like?
Their body contains:- head, foot and visceral mass.
🐚 shell of molluscs?
They have three 3 layers:-
Periostracum - Is the most outer layer, made up of protein molecules.
Perismatic - Very thick, made up of calcium carbonate.
Nacreous layer - Most inner layer, bright, shiny ✨ and made up of calcium carbonate.
What is Redula in Mollusks?
Redula is the in the different pattern and numbers in different animals.
Redula is found within mouth.
What is the function of Redula?
Rasping 👅 tongue like organ. It serve as conveyer belt it moves and bring food to the 👄 mouth of the organism.
Bivalves do not have redula.
Redula serve as?
Conveyer belt.
Redula is moved by muscles.
Who do not have Redula?
Bivalves do not have Redula.
Foot of molluscs?
Foot is used for locomotion, attachment, and combination.
Bivalves have what foot?
They have Hatchet 🪓 foot.
Different types of foot?
Outside the foot is incurrent and excurrent siphon,
Incurrent siphon ;- brings food and water 💧 to the mouth.
Excurrent siphon ;- takes the waste material out.
In molluscs Foot secretes what?
Foot secretes mucus,
And that mucus is used for Adhesion and slime tract.
Visceral portion of the body of Molluscs?
They have
Mantle and Mantle cavity.
Mantle ;- it is sheath of skin, and it secrets the shell of these organisms, it also Act as Gas exchanger.
Mantle cavity ;- is houses 🏠 respiratory organs, product from digestive, excretory and reproduction system emptied into Mantle cavity.
Mantle cavity is an area where digestive, excretory, and reproductive materials in Mantle cavity.
How can food, nutrient and water can be observed in molluscs?
The water and flow of blood goes opposite ways it called (countercurrent exchange mechanism) so that’s how the food nutrient and oxygen can be absorb.
What are blood sinuses?
Those are the openings that blood goes into and exchange of gases and nutrients occur between red blood cell.
Internal structure of molluscs?
Heart, blood vessels, blood sinuses.
A pair of kidneys,
Metanephridia ➡️ nephrostome ➡️coelomic area.
Duct of the kidney of molluscs?
May also serve as discharge of egg or sperm.
Nervous system have?
Neurosecretory cells.
And molluscs have advanced sense organs.
Reproduction of molluscs?
Most are dioecious, and some hermaphroditic(monoecious).
Trochophoroe larva (same to annelids)
Direct metamorphosis (life cycle do not change).
What is veliger?
It looks like adult bivalve.
In many Gastropoda and bivalves?
A uniquely molluscs itermediate larva stage which is called the veliger is hatched 🐣 with the begging of foot, she’ll, and mantle.
General characteristic of Molluscs?
We do not have one
But
Because in molluscs we have.
Snail;- univalve
Clam;- two shell.
Around the heart is pericardium ➡️ came from mesoderm.
Foot secretes mucus for adhesion and slime tract.
Class Monoplacophora?
Placo = something flat.
For long time they thought organism of this class are extinct, but they found them in the coast of coasta rica.
And they look like very very old molluscs.
Structure of class monoplacophora?
They are small round shell and creeping foot.
Organ are serially repeated (have metamorphosis).
Class polyplacophora?
Mail shell or chitons.
They are flattered dorsoventrally and have 8 plates or valves.
Water current of class polyplacophora?
Water current go through pallial groove and through gills.
Class polyplacophora have what in mantle groove?
They have sense organs in mantle groove.
Heart of class polyplacophora?
There have 3 chambers.
And have a pair of Metanephridia.
They ahvetrochophore stage but not veliger.
Class scaphopoda?
Tusk shell or tooth shells.
Foot of class scaphopoda?
Foot into sand & shell end into water.
Cilia extends From tentacles of head.