Parasites

• What is a Parasite?

  An organism which obtains its energy/food from living in or on another organism causing it harm.

  Ectoparasite - lives on the outside of another organism

  Endoparasite - lives on the inside of another organism
• Adaptions for parasitism in tapeworms

  • Hooks and suckers on scolex - penetration and attachment to gut wall
  • Lack of circulatory/digestive system - unnecessary due to lifestyle so it conserves its energy and recourses
  • Long flattened body - large surface area for absorption of nutrients
  • Body covered in thick cuticle - protection of digestive enzymes of host
  • Hermaphrodite - contains both male and female sex organs allowing them to reproduce by them self
• What are precautions that can be taken to avoid infection by tapeworm?

  • Thoroughly cook the infected pork
  • do not spread untreated sewage on land
• Tapeworm life cycle

  1. The adult lives in the human intestine and produces eggs which are carried in human faeces
  2. The pig ingests the eggs which hatch into larvae and infect the animal’s muscle by forming cysts
  3. If a person eats uncooked pork, the cysts are introduced into the body, where they attach to the intestine and mature into adult tapeworm
  4. Adult has both male and female reproductive organs (hermaphrodite)
• Adaptions for parasitism in head lice

  • Claws/pincers to hold onto hair
  • Large number of eggs to increase size of population
  • Holozoic - has a gut for digestion
  • Piecing mouthparts - suck blood from host's scalp
  • Separate sexes as a mate is easy to find