Transcript Phylum Platyhelminthes- Flatworms Tiger Flatworm

Phylum Platyhelminthes- Flatworms
Fluke
Planarian
Planarian
Tiger Flatworm
Tapeworm’s
sucker and
hooks
-Platyhelminthes consists of the unsegmented flatworms, which
includes both free-living and parasitic species. They have bilateral
symmetry, and can move by using layers of muscles, or in some
species, by gliding along a slime trail using cilia (like tiny hairs).
-Flatworms are slightly less developed than segmented worms due to
their open circulatory system and incomplete digestive system.
Instead, flatworms absorb nutrients through their skin. Some
flatworms have primitive light-sensing "eyes" that allow them to
move either towards or away from light, while other species have
different types of sensors on their bodies, including chemical,
balance, and water movement receptors.
-Most species of flatworms reproduce either sexually or asexually.
-Flatworms have an open circulatory system. This means that their
blood does not flow through vessels (veins), their blood surrounds
their organs. Oxygen and carbon dioxide move in and out of the
body through their skin.
-Platyhelminthes are an ancient phylum, but
practically nothing is known of their
evolutionary history because they have very
soft bodies which do not preserve well as
fossils.
-Platyhelminthes live nearly everywhere, on land,
in both fresh and marine waters as well as
inside other animals. Most of the free living
species are marine with only a small number
inhabiting fresh water and very few living on
land. Parasitic species normally move between
different habitats as they change life cycle
stages and hosts.
Surgeon
removes a
19 ft.
tapeworm!!
How does it get in there in the first place?
Eggs hatch as tiny creatures that lie on grass. Most of
them die, but one in about one in one thousand live and
may be swallowed by pigs or cows. Once in the cow or
pig it burrows into their flesh turning into something
called a bladder worm. Bladder worms can live for
about a year. If a human eats the infected meat, it can
turn into a tapeworm. It attaches on the walls of the
intestines and absorbs the nutrients from the host’s
food.
RELAX--- This is very rare!!!!! Also-cooking meat would
kill any parasite!