Lophotrochozoa II - Flatworms

Question 1

Commissural fibres

Answer 1

Axons that connect the two hemispheres of the brain

Question 2

Describe the nervous system of flatworms?

Answer 2

Two nerve chords
Transverse commissures linking the two nerve chords (sideways link)

Sense organs and integration at front

Question 3

What features do flatworms lack that are seen in other bilateria?

SCARAB

Answer 3

No body cavity (coelom)
Therefore no hydrostatic skeleton (limits power of locomotions)

No blood system

No skeleton

No appendages

No anus (food and waste same opening)

No gills or respiratory organs - means oxygen must reach cells by diffusion only so the flatworms are flat and small

Question 4

Simple is not

Answer 4

Simple doesn’t mean they are primitive (they might have just lost characteristics over time and that’s why they are simple rather than they are simple because they are an old ancestor)

Question 5

Which superphylum do through guts exist in?

Answer 5

Ecdysozoa
Lophotrochozoa
Deuterostomia

Question 6

Flatworms lack of anus

Answer 6

Not because they are primitive

Lack of anus was secondarily (lost)

Question 7

Polyclad

Answer 7

Marine flatworm

Question 8

Triclad or planarian

Answer 8

Freshwater flatworms

Question 9

Monogeneans

Answer 9

Flukes with one host

Question 10

Trematodes

Answer 10

Flukes with more than one host

Question 11

Cestodes

Answer 11

Tapeworms

Question 12

Name three parasitic flatworms

Answer 12

Monogeneans
Trematodes
Cestodes

Question 13

Name two free living flatworms

Answer 13

Triclads

Polyclads

Question 14

How do flatworms move

Answer 14

Cilia on their epidermis which they use to glide along. Also use muscular ripples.

Question 15

Size of flatworms

Answer 15

1-10mm

Question 16

What type of gut do freshwater flatworm species have?

Answer 16

Three branches gut

Question 17

What type of mating do freshwater flatworm species undergo? XX

Answer 17

Reciprocal

Question 18

What do flatworms hunt?

Answer 18

Earthworms

Question 19

Which flatworms hunt?

Answer 19

Freshwater (planarians/triclads) hunt worms and snails

Marine species (polyclads) hunt worms and snails

Question 20

Characteristics of polyclad marine flatworms

Answer 20

Bright colours
Some can swim
Hermaphrodites
Hunters

Question 21

Characteristics of freshwater flatworms (planarians/triclads)

Answer 21

Hermaphrodite 
Reciprocal mating
No larvae 
Hunters 
Three branches gut

Question 22

Important characteristic freshwater flatworms (planarians and triclads) are known for

Answer 22

Regeneration

Question 23

How do freshwater flatworms regenerate?

Answer 23

Stem cells called neoblasts are through the body; when sections of the work are amputated these cells are activated and reform the lost tissues.

Question 24

Why might have planarian regeneration have evolved? XX

Answer 24

Planarians adapt to starvation by shrinking

Question 25

Name two parasitic flatworms

Answer 25

Flukes

Tapeworms

Question 26

Ectoparasites on fish

Answer 26

Monogenea

Question 27

How do tapeworms attach to the gut

Answer 27

Scolex (head with grooves and suckers)

Question 28

What type of parasites are Trematodes

Answer 28

Endoparasites

Question 29

Examples of Trematodes (two)

Answer 29

Blood fluke

Chinese liver fluke

Question 30

How many hosts in a Trematodes life cycle?

Answer 30

More than 1

Question 31

Proglottids

Answer 31

Segment of a tapeworm containing both male and female reproductive organs

Question 32

Cestodes (tapeworms) don’t have what

Answer 32

A gut

Absorb nutrients through special skin

Question 33

Important feature of parasitic Platyhelminthes (tapeworms and flukes)

Answer 33

Neodermata (new skin)

Question 34

What evidence is there that tapeworms and flukes are a monophyletic group?

Answer 34

They have ‘new skin’ in common