Create an account
the head foot consist of what
the head, which contains the mouth and sensory structures; the foot- a large muscular organ for locomation
gastropods have an open circulatory system in which the heart pumps _____________ from gills or lungs into the hemocoel.
how do snails survive dry periods
by retreating into their shells and sealing the opening with their mucus plug
Pteropods or "sea butterflies"
have a foot that is modified into a winglike flap and used for swimming rather than crawling
tentacles, bear like jaws on the head, a very advanced nervous sysytem, and a closed circulatory system
the chambered nautilus shell is
coiled and divided into a series of chambers, the body is confined to the outer most chamber
Annelids of the class Oligochaeta generally live
in the soil or in fresh water and have no parapodia
_____________ and ________________ muscles line the earthworms interior body wall
circular and longitudinal
Soil moves through these structure;
mouth, pharynx,esophagus,crop,gizzard intsetine(includes the typhosole) and anus
____________________ are found in all segments but are concentrated at the anterior end
____________and _________ diffuse through the skin, which contains many small blood vessels and must be kept moist.
Oxygen and Carbon dioxide
Contractions of the ________________ and the dorsal blood vessels force blood through the closed circulatory system
Earthworms are _______________________
hermaphrodites, but an individual worm cannot fertilixe its own eggs
during mating thay are held together by their setae and a film of mucus secreted by each worm's
The _________________ from each worm move through the mucus to the seminal receptacle of the other.
______________________ occurs inside the tube, which forms a protective case for the young worms
what is advantage of true coelom over pseudocoelom
with a coelom the muscles of the body wall are seperated from those of the gut, therefore the body wall muscles can contract without hindering the movement of food through the gut. A coelom also provides a space where the circulatory system can transport blood without interference of internal organs
why are land snails more active when the air around them is moist
the thin membrane lining the mantle cavity must be kept moist to allow gases to diffuse through it
Compare circulatory system of 3 major classes of mollusk
gastropods have open circulatory system meaning the circulatory fluid called hemolymph does not remain entirely within the vessels; Cephalopoda have a closed circulatory system, it transports fluid more rapidly than an open circulatory system, thus nutrients, oxygen, and carbon dioxide are carried quickly through the body;Bivalva have
identify the structure that provides the basis for dividing annelids into three classes;
the number of setae and the presence or absence of parapodia
Advantages of body segmentation
if one segment becomes disabled, the others can still function; movement is possible by segmentation; segmentation enables different parts of the body to carry out variuos functions independently;
how are an earthworms circular and longitudinal muscles used in locomation
the worm anchors some of the middle segments by their setea & the ability to contract the circular muscles in front of the middle segments allows the worm to move
why does an earthworm require a moist environment to survive
an earthworm requires a moist environment to survive because it diffuses oxygen and carbon dioxide through the skin, which contains many small blood vessels- this exchange of gases can only take place if the skin is moist, secretions of mucus and the presence of a thin cuticle also help keep the worms skin moist
naked gill, which refers to the fact that gas exchange occurs during the entire body surface of these animals
Please allow access to your computer’s microphone to use Voice Recording.
Having trouble? Click here for help.
We can’t access your microphone!
Click the icon above to update your browser permissions and try again
Reload the page to try again!Reload
Press Cmd-0 to reset your zoom
Press Ctrl-0 to reset your zoom
It looks like your browser might be zoomed in or out. Your browser needs to be zoomed to a normal size to record audio.
Please upgrade Flash or install Chrome
to use Voice Recording.
For more help, see our troubleshooting page.
Your microphone is muted
For help fixing this issue, see this FAQ.
Star this term
You can study starred terms together