Phylum Platyhelminthes | Biology for JAMB PDF Download

Phylum Platyhelminthes, commonly known as flatworms, encompasses a diverse group of invertebrate animals. They exhibit unique characteristics and adaptations, making them a significant topic in the field of biology. Here are some key points to remember about Phylum Platyhelminthes:

• Body Structure: Flatworms have dorsoventrally flattened bodies with distinct anterior and posterior ends. They lack a body cavity or coelom and are bilaterally symmetrical. The body surface is covered by a protective tegument.
• Digestive System: Platyhelminthes display different types of digestive systems. Some have a simple gastrovascular cavity with a single opening, while others, especially parasites, absorb nutrients directly from their hosts.
• Nervous System: Flatworms possess a ladder-like nervous system, consisting of longitudinal nerve cords and transverse nerves. Their centralized nerve mass, known as cerebral ganglia, serves as the brain.
• Reproduction: Platyhelminthes exhibit various reproductive strategies. Many species are hermaphroditic, meaning they have both male and female reproductive organs. They can also reproduce asexually through fragmentation or budding.
• Habitat and Feeding: Flatworms inhabit diverse environments such as marine, freshwater, and damp terrestrial habitats. Their feeding habits vary depending on the species. Some are free-living and feed on small organisms, while others are parasitic and derive nutrients from their hosts.

Common Examples of Phylum Platyhelminthes:

• Planaria: Planaria is a well-known example of free-living flatworms found in freshwater environments. They are often used in biological research.
• Liver Fluke: Fasciola hepatica is a parasitic flatworm that infects the liver of mammals, including humans and livestock. It causes a disease called fascioliasis.
• Tapeworm: Tapeworms are intestinal parasites that inhabit the digestive tracts of vertebrates. Species such as Taenia solium (pork tapeworm) and Taenia saginata (beef tapeworm) are common examples.
• Monogeneans: Monogeneans are primarily parasitic flatworms that infect the skin and gills of fish. They have direct life cycles and require only one host for completion.

Understanding the key concepts of Phylum Platyhelminthes and familiarizing yourself with the common examples mentioned above will enhance your knowledge of this diverse group of organisms.