chapter 36 section 1 Flashcards
what is a pharynx
muscular tube where food is ingested in planarians
tegument
sheet of fused cells on the external surface of a fluke
fluke
a leaf shaped flatworm that parasitizes many kinds of animals
tapeworm
live in the intestines of almost all interior vertebrates
primary host
host where adult parasite derives nourishment
intermediate host
host where larvae derive their nourishment
flatworms are the simplest animals with
bilateral symmetry
the gastrovascular cavity of a flatworm
has a single opening
one difference between free living flatworms and parasitic flatworms is that
parasitic flatworms usually have a simpler structure
the eggs of the blood fluke “Shistosoma”
leave the primary host in feces or urine
the primary hosts of beef tapeworms are
humans
what is the primary host of a blood fluke
humans
what is the intermediate host of a blood fluke
snails
how does a blood fluke enter its primary host
a tailed larva bores through exposed skin of a human
what stage of the beef tapewrom life cycle is spent inside a cyst
the larval stage
how do planarians eliminate excess water from their bodies
Flame cells collect excess water, which is then transported
through excretory tubules and excreted from
numerous pores scattered over the body surface.
how do planarians and tapeworms differ in their ability to detect light
Planarians detect the intensity and direction of
light with two eyespots; tapeworms cannot detect
light.
some people mistakenly believe that all organisms are perfectly adapted to their environments. what aspect of blood fluke reproduction suggests that these flatworms are not perfectly adapted to the environment inside their human hosts
The eggs sometimes block blood vessels, causing
a disease that may kill the host. A parasite that
kills its host may not be perfectly adapted to its
environment.
