Acoelomates with bilateral symmetry

Question 1

bilateral symmetry

Answer 1

HAVE front/back, HAVE left/right

ALL ANIMALS with bilateral symmetry have endoderm (internal), mesoderm (middle) & ectoderm (external) tissue layers (TRIPLOBLASTIC)

EITHER Protostome or Deuterostome

Most are NOT SEGMENTED, six phyla that ARE segmented

Question 2

Ph. Platyhelminthes

Answer 2

– flatworms, flukes, tapeworms
– Bilateral, Acoelomate, Protostomes, non-
segmented
– predators, parasites, scavengers
– freshwater, marine, terrestrial

Question 3

Flatworms

Answer 3

in phylum Platyhelminthes

have complex organ systems and tissues; waste disposal system; complex nervous system

HERMAPHRODITES –eachindividual has both male & female reproductive parts; can fertilize their own eggs OR can fertilize each other

many are parasitic

Question 4

Trematoda

Answer 4

parasitic animal in phylum Platyhelminthes

(liver/lung flukes, schistosomes); most use asexual reproduction; complex life cycle with multiple hosts

Question 5

Schistosomes

Answer 5

Trematoda in phylum platyhelminthes– kill ~200,000 people/yr, 100M-700M at risk

from parasites in contaminated water

sexual reproduction –female carries male around –so, they are NOT hermaphrodites, have two sexes for mating (known as DIOECIOUS)

Question 6

Tapeworms (Cestoda)

Answer 6

in phylum Platyhelminthes

digestive tract parasites in animals; Composed of segments called PROGLOTTIDS, which are filled with eggs and are excreted with feces, & can infect other animals; Scolex is used to attach to intestinal wall

Taenia: mature proglottids

Question 7

Ph. CYCLIOPHORA

Answer 7

Bilateria, Protostomes, Non-segmented, Acoelomate; live on lobster mouthparts; discovered in 1995; commensals (+,0) that gain structure and food from living on lobster mouthparts