Flatworms roundworms notes

Warm up

1. What are some characteristics that flatworms and cnidarians share?

2. What are some characteristics that are different?

Platyhelminthes

The flatworms

Bilateral Symmetry

3 tissue layers

No body cavity

Mouth but no anus

Branched intestines

Feed on small animals; scavengers

Parasites; tapeworms

No skeleton; Body cavity is fluid filled to move and keep shape

Sexual reproduction, but hermaphroditic

Live in all environments

Primitive muscles!

Many parasitic for humans

Definite nerve organs including eyespots for sensing light

Most primitive of the bilateral animals!!!

CEPHALIZATION: definite head end

Collection of nerves in the head; ganglia

Hymenolepis dimunataThis is how tapeworm attach to a host.They are found in uncooked meat and fecal material.The host can become VERY SICK!!!

Bilharzia burrows through you skin and moves to your gut. The host becomes very sick. It comes from fouled water. ~250,000,000 people are infected

Sparganosis is from infected water.

Humans can get it from reptiles, birds, & other mammals that have it.

They can grow up to 14 inches.

This flatworm can infect the brain or eyes.

Most common in eastern Asia!

Nematoda

The roundworms

Bilateral

Digestive cavity

Mouth and anus

Feed on just about anything

Many harmful parasites to humans!

No skeletonSexual reproductionFound everywhereName means thread-like

No circulatory system

Look like worms, but are NOT!

Coelom (body cavity type body plan)

Two nerve cords that transmit impulses

These parasites have teeth-like plates to attach them to the intestinal tract.

Hookworms can each drink 1.0 ml (1/2 cup) of blood per day.

You can get them by walking barefoot then they burrow into your skin and move to your blood.

Trichinella roundworms in human muscle

Whipworm found in 50% of puppies;Transmitted to human owners

Most common childhood intestinal parasite