Only MIA kids can understand this.
Platyhelminthes is one of the phyla in the kingdom Animalia whose members include all kinds of worms that have a dorsoventral flat body shape. The name “Platyhelminthes” itself came from the Greek language, “platy-” meaning flat and “helminth” meaning worm.
Characteristics of Platyhelminthes:
– Has a flat body shape.
– Doesn’t have a coelomic.
– Bilateral symmetrical, triploblastic body.
– Digests with gastrovascular.
– Breathes with its entire body surface.
– Doesn’t have a blood circulatory system.
– Has a ganglion as a nervous system.
– Has flame cells as an excretory system.
– Generally is hemaphroditic, which means bisexual namely male and female in one individual but there is rarely a self-fertilization.
Body structure of Platyhelminthes:
Platyhelminthes has a flat-shaped body without segments which can be divided into anterior (head), posterior (tail), dorsal (back), ventral (opposite area of dorsal), and lateral (sides). Platyhelminthes has a bilateral symmetrical body; this animal is triploblastic comprised of three tissue layers; ectoderm (outer layer), mesoderm (middle layer), and endoderm (inner layer).
Classification of Platyhelminthes:
Platyhelminthes is divided into four classes; Turbellaria, Trematoda, Cestoda, and Monogenea.
Planaria sp. is an example of species included in the class Turbellaria. This worm is carnivorous and lives freely in waters like rivers, ponds, and lakes. Planaria has a body length of 5-25 mm. This animal moves with cilia in its epidermis.
Planaria has a very simple digestive system comprised of a mouth, a pharynx, and a gastrovascular segment. This animal doesn’t have an anus that the undigested leftovers will be reissued by mouth.
All members of this class are parasites that live inside the bodies of humans or animals. These worms have a sucker in their mouth or ventral with chitin teeth. Trematoda’s body surface doesn’t have cilia but has cuticula to protect itself.
An example is Fasciola hepatica (liver worm).
Example: Taenia saginata
Example: Schistosoma mansoni