BIOB34H3 Lecture Notes - Cestoda, Hemoglobin, Endostyle
Document Summary
Slide 3: tapeworms are endoparasites (they live in the gut of the host). The stuff inside the proglottid is filled with gonads so they have a huge capacity to reproduce: these tapeworms are primarily gutless, meaning none of their ancestors ever had a gut. These tapeworms evolve from ancestors that never had a gut. The barnacle larva approaches a host, and injects the mass of undifferentiated cells into the crab. The mass of undifferentiated cells is basically the parasitic barnacle. The other barnacles have a gut but the related parasitic barnacle doesn"t. This means the parasitic barnacle is secondarily gutless, meaning they evolved from an ancestor with a gut. Over evolutionary time, once they adopted a parasitic lifestyle, the gut was no longer needed and the trait was lost. They pass water through their body tissues, and filter out any food in the water that they can eat. Slide 6: the large opening is called the osculum.
