130 likes | 402 Views
Platyhelminthes. By: Andrew Ibach & Jennifer Kapinus. Platyhelminthes Common Name: Flatworm. Three classes: Turbellaria Free-Living Flatworm Trematoda Flukes Cestoda Tapeworms. Body Symmetry. Bilateral If split in half, left and right, both sides would be identical to each other
E N D
Platyhelminthes By: Andrew Ibach & Jennifer Kapinus
PlatyhelminthesCommon Name:Flatworm • Three classes: • Turbellaria • Free-Living Flatworm • Trematoda • Flukes • Cestoda • Tapeworms
Body Symmetry • Bilateral • If split in half, left and right, both sides would be identical to each other • Cephalization • Concentration of sensory equipment in one end, the head, of the organism
Body Plan • Dorsally, ventrally flat • Triplpoblastic (three tissue layers) • Endoderm • Mesoderm • Ectoderm • Acoelomate (no body cavity between the digestive cavity and outer body wall)
Support & Movement System • Turbellians use cilia to move • Trematoda & Cestoda rely on the host's circulation
Nutrition • One digestive opening • branches to all parts of the body. • Turbellarianshave a muscular pharynx to move food which they get from eating mollusks and worms. • Parasitic classes rely on the host for digestion, absorbing nutrients from the host.
Gas Exchange • No organs for respiration • Diffusion from body surface to body cells
Excretion/ Water Balance • Osmotic balance with environment • Protonephridia • Networks of tubules with ciliated structure called fame bulbs that pull fluid through branched ducts opening to the outside.
Reproduction • Sexual Reproduction • Males pierces female’s body surface and releases sperm into her • Asexual Reproduction • Budding • Self-fertilization • Fission
Response to Stimuli • Eyespots • Light sensitive • Nerve System • Ganglions by eye spots • Nerves run all the way along body from ganglions • Can learn to modify responses to stimuli
Defense Mechanisms • Bright colors • Associated with bad taste due to toxins inside flatworm • This deters predators from attacking the brightly colored prey again.
Other Information • Flatworms are primarily aquatic • Flatworms have no circulatory organs • There are no open cavities in a flatworm