chapter 36 section 1

Question 1

what is a pharynx

Answer 1

muscular tube where food is ingested in planarians

Question 2

tegument

Answer 2

sheet of fused cells on the external surface of a fluke

Question 3

fluke

Answer 3

a leaf shaped flatworm that parasitizes many kinds of animals

Question 4

tapeworm

Answer 4

live in the intestines of almost all interior vertebrates

Question 5

primary host

Answer 5

host where adult parasite derives nourishment

Question 6

intermediate host

Answer 6

host where larvae derive their nourishment

Question 7

flatworms are the simplest animals with

Answer 7

bilateral symmetry

Question 8

the gastrovascular cavity of a flatworm

Answer 8

has a single opening

Question 9

one difference between free living flatworms and parasitic flatworms is that

Answer 9

parasitic flatworms usually have a simpler structure

Question 10

the eggs of the blood fluke “Shistosoma”

Answer 10

leave the primary host in feces or urine

Question 11

the primary hosts of beef tapeworms are

Answer 11

humans

Question 12

what is the primary host of a blood fluke

Answer 12

humans

Question 13

what is the intermediate host of a blood fluke

Answer 13

snails

Question 14

how does a blood fluke enter its primary host

Answer 14

a tailed larva bores through exposed skin of a human

Question 15

what stage of the beef tapewrom life cycle is spent inside a cyst

Answer 15

the larval stage

Question 16

how do planarians eliminate excess water from their bodies

Answer 16

Flame cells collect excess water, which is then transported
through excretory tubules and excreted from
numerous pores scattered over the body surface.

Question 17

how do planarians and tapeworms differ in their ability to detect light

Answer 17

Planarians detect the intensity and direction of
light with two eyespots; tapeworms cannot detect
light.

Question 18

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

Answer 18

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.