Biology Questions and Answers

(Greg DeLong) #1

Biology Questions and Answers


The body of gastropods is divided into
three main pmass and foot.ortions: head, the visceral



  1. What is the type of
    digestive system in molluscs?


Molluscsand a complet present extracellular de digestive system, withigestion
mouth and anus.



  1. What is the radula? What is
    the function of this organ?


Some molluscsstructure with harsh have a tonsaliences similargue-like (^) to
small teeth. This structure is called
radula. Thelps to scrape fhe radula projects outside ood. and



  1. How is the respiratory
    system in aquatic molluscs
    characterized? What adaptive
    respiratory structure do
    terrestrial molluscs present?


Aquatic molluscs oxygenate their blood


through gills in direct contact withwater. In terrestrial molluscs the rich (^)
vascularityabsorbs air d under the mantle cavityoing the role of a primitive (^)
lung.



  1. Which type of circulatory
    system do molluscs have?
    How can it be compared to the
    respiratory system of
    annelids?


Molluscs,cephalopods, have an open circulatory with the exception of (^)
system, i.e., the blood circulates within
vessels,open lacunas o from thr cavities.e heart, b In annelids thut it also fills (^) e
circulatory system is closed, i.e., the
blood circulatesvessels. only inside blood



  1. How is the large size of
    some cephalopods related to
    the type of circulatory system
    they present?
    In cephalopoclosed and this pds the circulatoryrovides more speed system is
    and pressure for the blood circulation


allowinlarge bodies, like octog the existence of species withpuses and giant (^)
squids.



  1. How is the excretory
    system of molluscs
    characterized?
    Molluscs have one or two pair of
    spongelike nephridia, similar to kidneys.


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