general zoology

• Annelids, such as earthworms and leeches, are invertebrates that have segmented bodies and bristles called setae.
• Phylum Platyhelminthes, also known as Flatworms, are usually flattened dorsoventrally, triploblastic, acoelomate, and bilaterally symmetrical.
• Unsegmented worms, members of the class Cestoidea are strobilated.
• Incomplete gut is usually present in Platyhelminthes, but it is absent in Cestoidea.
• The length of the body varies from 1mm to 25 m in the phylum Platyhelminthes.
• The pair of lateral nerve cord in scolex extends towards the end of the strobili in the phylum Platyhelminthes.
• The protonephridial system is used for excretion in the phylum Platyhelminthes.
• Examples of species in the phylum Platyhelminthes include the pork tape worm (Taenia solium) and the beef tapeworm (Taenia saginata).
• Somewhat cephalized, with an anterior cerebral ganglion and usually longitudinal nerve cords, Platyhelminthes are protonephridia as excretory/osmoregulatory structures.
• Most forms of Platyhelminthes are monoecious, with complex reproductive systems.
• The nervous system of Platyhelminthes consists of a pair of anterior ganglia with longitudinal nerve cords connected by transverse nerves and located in the mesenchyme.
• Protonephridia that end in flame cells are used for excretion in Platyhelminthes.
• A pair of anterior ganglia with longitudinal nerve cords connected by transverse nerves is present in Platyhelminthes.
• Over 20,000 species of Platyhelminthes were identified.
• Parasitic flatworms feed on the nutrients of their host.
• Free-living flatworms derive nutrients from scavenging or by eating other animals.
• Flame cells are used for the removal of wastes in Platyhelminthes.
• Ganglia and nerve cord is used for stimuli in Platyhelminthes.
• Some flatworms have eyespot used for light detection.
• Free-living flatworms reproduce via asexual reproduction through binary fission.
• Most parasitic flatworms are hermaphroditic and reproduce through sexual reproduction.
• Class Turbellaria are free-living in bottom of ponds, streams and marine waters.
• Turbellaria vary in color and possess rhabdites in the epidermis for protection.
• Gas exchange and excretion occurs via diffusion in Turbellaria.
• Two simple eyespot called ocelli are used to detect light in Turbellaria.
• Turbellaria are reproduced by transverse fission.
• Some species of Turbellaria are hermaphroditic, including Planaria and Notoplana.
• Monogenea are flukes with only one generation in their life cycle and are commonly found attached to the gill filaments of fishes.
• Opisthaptor, a posterior attachment organ, enables Monogenea to anchor itself to the gill filament and feed on mucus, blood and epithelial cells.
• Gyrodactylus and Sphynura are examples of Monogenea.
• Monogenea have a flat, oval to elongated body shape and are parasitic.
• The tegument is the outer body wall made up of glycocalyx that aids substances across the wall and it protects the flukes against the host destructive enzymes.
• The digestive tract of Monogenea has a mouth, a muscular pharynx, and pouches.
• Reproduction in Monogenea is complex.
• Trematoda have a flat, oval to elongated body shape and are parasitic.
• The tegument is the outer body wall made up of glycocalyx that aids substances across the wall and it protects the flukes against the host destructive enzymes.
• The digestive tract of Trematoda has a mouth, a muscular pharynx, and pouches.
• Trematoda can be found either external or internal part of the host body.
• Trematoda have multiple host, with the primary host usually vertebrates and fresh water snails as intermediate host.
• Examples of Trematoda include Liver flukes (Fasciola hepatica), Blood flukes (Schistosoma spp.).