Phylum Platyhelminthes

Question 1

What are Platyhelminthes?

Answer 1

Flat worms.

Question 2

What are five characteristics of Platyhelminthes?

Answer 2

1) Cephalization—have a head
2) Brain
3) Nervous system
4) More advanced gut
5) Mouth

Question 3

What is the difference between a parasite and a free living organism?

Answer 3

Parasites need to be living in/on a host to survive, while free living organisms do not need a host

Question 4

What are flukes?

Answer 4

Parasitic flatworms often found in fish that can also be found in humans—in the blood.

Question 5

What are planaria?

Answer 5

Free living flatworms found in fresh water that can regenerate and are biological indicators.

Question 6

What are marine flatworms?

Answer 6

Free living flatworms that are very colorful.

Question 7

What are tapeworms?

Answer 7

Parasitic flatworms found in cows, pigs, and humans with hooks in their mouths.

Question 8

Describe the beef tapeworm life cycle.

Answer 8

1) Tapeworm eggs in the grass are eaten by cows, then hatch and move to the muscle.
2) The worm forms a cyst.
3) The cow is taken to the butcher and made into steak.
4) The steak is cooked. If it’s not cooked thoroughly enough, the worm can survive and get taken to a person’s stomach.
6) The worm—if it survives the stomach—can move to the small intestine, where it feeds off meals the host eats.
7) The worm can lay eggs (100,000 per day) that can be taken to fields if the host uses the bathroom there. This can start the cycle all over again.

Question 9

Why are beef tapeworms not much of a problem where we live? (Four reasons)

Answer 9

1) We have food inspectors.
2) Most meat is cooked thoroughly.
3) Many people can afford medicine here.
4) We have sewage treatment.