BIO 221 Lecture Quiz 1 Study Guide

What is the general features of Mollusca?

‘soft body’ (e.g., snails, mussels, octopuses)

protostomia, lophotrochozoa (trochophore larva)

What is the coelom of Mollusca?

Spiral cleavage, eucoelomate → development through schizocoely

coelom can be limited, e.g., space around heart, kidneys, and gonads

Is Mollusca protostome or deuterostome?

Protostomia

What is Mollusca life cycle?

Egg → trochophore larva → (A) either direct development (polyplacophora) or -. (B) development into veliger larvae (e.g., gastropods and bivalves)

What is Mollusca circulatory system?

Counter-current exchange

open circulatory system: pumping heart, blood vessels, and blood sinuses

What is Mollusca 2-parted body

1. Head-foot portion

   1. feeding, sensory, locomotor organs

   2. 'well developed head with sensory organs and mouth with radula

2. visceral mass portion

   1. digestive, circulatory, respiratory, and reproductive organs

What are the layers of shell of Mollusca?

outer: periostracum

middle: prismatic layer

inner: nacreous layer

What is the feeding organ in Mollusca?

mouth, esophagus, stomach, digestive glands, intestines and anus

What are the differences between bivalves and mollusca?

bivalves don’t have radula

Head-Foot portion

Head portion

Radula: rasping, tongue-like organ: it bears up to 250,000 backward pointing teeth

muscles move radula over odontophore; move forth-and-back to scrape, cute, tear food

conveyor belt for food

Foot portion

locomotion, attachment to ground

waves of muscular contractions result in creeping locomotion

many modifications of foot

snail and bivalves: foot extends hydraulically

Visercal mass portion

mantle: dorsal sheath of skin for protection of soft parts and forms a mantle cavity

secretes the shell

mantle cavity: houses gills/lungs for gas exchange

mantle with sensory receptors: water quality