Phylum Platyhelminthes

Question 1

what group makes of platyhelminths?

Answer 1

flatworms (can be free living or parasitic)

Question 2

do platyhelminths have a coelum?

Answer 2

they are acoelomates

Question 3

how many tissue layers do platyhelminths have?

Answer 3

3 triploblastic

Question 4

nervous system of platyhelminths

Answer 4

• have distinct nerve cords
• anterior region with sensory structures
• first animals to have communication between nerves through the chemical messenger acetylcholine

Question 5

what are some classes of flatworms?

Answer 5

• turbellaria
• trematoda
• cestoda

Question 6

characteristics of turbellaria

Answer 6

(planarians) 
The most primitive group of flat worms. Most members are free-living and marine, though a few species are parasitic. 
-can regenerate if you cut them in half 
-hermaphrodoitic 
-have an incomplete digestive tract

Question 7

characteristics of trematoda

Answer 7

• flukes

- parasitic

Question 8

characteristics of cestoda

Answer 8

-Tapeworms
-Most adults are endoparasites of vertebrates
parasitic
-has a head (scolex) which attaches itself and then a series of proglottids that are reproductive segments

Question 9

what are ocelli? (in planarians)

Answer 9

• eyespots, used in light detection

- paired with auricles used for chemosensory detection

Question 10

what is the scolex? (in tapeworms)

Answer 10

the mouth that tapeworms use to latch on to hosts (has hooks and suckers)

Question 11

what are proglottids? (in tapeworms)

Answer 11

• contain male/female gonads

- excreted in the hosts feces