Platyhelminthes

1. What are the best known
representatives of the
platyhelminth phylum?
2. What is the main external
morphological feature that
differentiates platyhelminthes
from other worms
(nematodes)?
3. How many germ layers
originate the body of
platyhelminthes? In relation
to this characteristic how are
these animals classified?
4. What are the types of
digestion and of digestive
system of platyhelminthes?
5. How are nutrients
distributed by the digestive
system in planarias?
6. How is gas exchange done
in flatworms?
7. Poriferans and cnidarians
do not have excretory
systems. Do platyhelminthes
have an excretory system?
8. What is an example of
freshwater flatworm? Due to
that habitat what is the
physiological problem that
these animals must solve?
9. Is the nervous system in
platyhelminthes more or less
sophisticated than in
cnidarians? What are the main
neural structures found in
flatworms? How is this neural
organization important for the
diversity of biological niches
explored by species of the
phylum?
10. What is cephalization?
How does lateral symmetry
favour cephalization?
11. What is the type of
reproduction, sexual or
asexual, that occurs in
platyhelminthes?
12. How can asexual
reproduction in planarias be
described?
13. Are flatworms monoecious
or dioecious?
14. Is it possible for a
hermaphrodite species to
present cross-fecundation?
15. What is direct
development? Is there a larval
stage in planarias?
16. Into which classe sare
platyhelminthes divided? How
are these classes
characterized and what are
some representative beings of
each of them?
17. What are the main human
diseases caused by
platyhelminthes?
18. Platyhelminth identity
card. How are platyhelminthes
characterized according to
examples of representing
beings, basic morphology,
type of symmetry, germ layers
and coelom, digestive system,
respiratory system, circulatory
system, excretory system,
nervous system and types of
reproduction?