Helminths
,• Helminths (parasitic worms)
• Eukaryotic
• Multicellular animals
• Chemoheterotrophic
• Kingdom: Animalia
• Phylum: Platyhelminthes (flatworms)
• Class: Trematodes (flukes)
• Class: Cestodes (tapeworms)
• Phylum: Nematodes (roundworms)
, We will focus on parasitic worms (helminths)
•Characteristics of parasitic animals
•They may have a reduced digestive system
•They may have a reduced nervous system
•The generally have very complex life cycles
•Parasitic worms (helminths) go through many
developmental stages in (often) several hosts
•Each stage is referred to as a LARVAL stage
•Dioecious - each adult is only one sex (most NEMATODES!)
•Monoecious - each adult is BOTH sexes (true hermaphrodite -
most PLATYHELMINTHS! )
•The generally have very complex life cycles:
•The DEFINITIVE HOST harbors the adult
•INTERMEDIATE HOSTS harbor larval stages
,• Helminths (parasitic worms)
• Eukaryotic
• Multicellular animals
• Chemoheterotrophic
• Kingdom: Animalia
• Phylum: Platyhelminthes (flatworms)
• Class: Trematodes (flukes)
• Class: Cestodes (tapeworms)
• Phylum: Nematodes (roundworms)
, We will focus on parasitic worms (helminths)
•Characteristics of parasitic animals
•They may have a reduced digestive system
•They may have a reduced nervous system
•The generally have very complex life cycles
•Parasitic worms (helminths) go through many
developmental stages in (often) several hosts
•Each stage is referred to as a LARVAL stage
•Dioecious - each adult is only one sex (most NEMATODES!)
•Monoecious - each adult is BOTH sexes (true hermaphrodite -
most PLATYHELMINTHS! )
•The generally have very complex life cycles:
•The DEFINITIVE HOST harbors the adult
•INTERMEDIATE HOSTS harbor larval stages
