Invertebrates I Phylum Platyhelminthes

Front 1

What are the three classes for Platyhelminthes (flat worm)?

Back 1

Turbellaria (flat worms)
Trematoda (flukes)
Cestoda (tapeworms)

Front 2

Which are parasitic and which are free living organism (they don't have to live in a host)

Back 2

**Tubellaria (flat worms) --- free living

**Trematoda and Cestoda are parasitic

Front 3

Platyhelminthes (flat worms) posses how many germ layers and what are they

Back 3

3 germ layers:

1. ectoderm
2. mesoderm
3. endoderm

mesoderm= muscle tissue (more revelent to us) --> leads to organ development

Front 4

Flatworms have an ______ of organization, whereas cnidarians have only _____ levels

Back 4

**organ-level of organizaitons
**a tissue level

Front 5

Why is flatworm differ from cnidarians? two major differences are

Back 5

flat worm have

1. bilateral symmetry and some

2. Cephalization (brian)

Front 6

Similar to cnidarians, flatworms are _____ and lack a _____

Back 6

1. acoelomate

2. a true body cavity (coelom) b/w the intestine and the body wall.

Front 7

instead they have a _____ surrounding thier organ systems

Back 7

solid mass of cells

Front 8

what does acoelomate mean

Back 8

have no body cavity at all. Organs have direct contact with the epithelium. Semi-solid mesodermal tissues between the gut and body wall hold their organs in place.
**no body cavity b/w intestine and body wall

Front 9

[Organ System: Digestive systems] The gastrovascular cavity consists of _______

Back 9

a mouth, a pharynx, and a three-branched gastrovascular cavity

Front 10

While feeding the pharnx ____ (what does it do)

Back 10

the pharynx extends out of the mouth and secretes digestive enzymes

Front 11

Food is pulled into the gastrovascular cavity by

Back 11

contraction of the pharynx

Front 12

undigested waste are expelled from the _____

Back 12

mouth

Front 13

[Nervous System] Does flatworm have a nervous system? If so how is it organized

Back 13

Yes. Flatworms have a nervous system organized like a ladder called the "nerve ladder"

Front 14

The nerve ladder is arranged into two _____, which runs along the ______axis and are connected by _______ nerve cords

Back 14

lateral nerve cords, which runs along the longtitudinal axis and are connected by transverse nerve cords

Front 15

Cephalization is observed at the

Back 15

anterior end

Front 16

These enlargements are know as the

Back 16

crebral ganglia

Front 17

or genetically called as the

Back 17

brain

Front 18

The neurons are organized into sensory associated with

Back 18

motor neurons

Front 19

The most sensitive neurons are the ___

Back 19

pigmented eyespots
**they are light sensitive and allow the planaria to respond to varying light intensities though no imaging occurs

Front 20

[Excretory/osmoregulatory system] Flatworms contain excretory organs called

Back 20

protonephridia-- are blind ended tubes that open to the outside via pores

*also contain flame bulb

Front 21

what is protonehridia? function?

Back 21

Regulate ion balance (osmoregulation). Function mainly to control water balance

**similar to a contractile vacuole in protozoans

Front 22

Cilia lining the protonephridea create

Back 22

a negative pressure that pulls fluid into the tube.

**Fluid is excreted out the opening

Front 23

[Reproductive system] list

Back 23

**Most flatworms are Monoecious (they contain both ovaries and testis)

**undergo asexual (by regeneration) or sexual reproduction.

**cross-fertilization--- occurs w/ each individual donating sperm to the other