Parasitic Nematodes Infect nearly every major animal group as well as plants. More complex life cycles compared to free living nematodes. They usually include at least one obligate intermediate host. Many take extensive internal mirgations through the host.
Soil Transmitted Helminths: Roundworms, Hookworms, and Whipworms Life Cycle is similar in all three groups and life cycles involve a single host. (1) Adults live in the intestine. (2) Eggs shed with feces and infect the soil. (3) Infection occurs as a result of ingestion of eggs (roundworms and whipworms) or infection via larval worms (hookworms). Hookworms is the second image. Whipworms was neglected in class
Parasitic Nematodes with multiple hosts Dracunculus medinensis or Guinea Worm (First image) Filarial Worms Heartworms (Dirofilaria immitis)