Phylum Platyhelminthes: Flatworms

Question 1

Flatworms have what type of symmetry?

Answer 1

simplest animals with BILATERAL symmetry

Question 2

Do flatworms have a head?

Answer 2

yes, characterized by cephalization in the anterior end of the organism

Question 3

How thick is a flatworm?

Answer 3

only a few mm thick

Question 4

Are bodies of flatworms divided into segments?

Answer 4

no

Question 5

Flatworms have more developed organs than _______ and _________

Answer 5

cinidarians

poriferans

Question 6

What are the 2 life forms flatworms occur in?

Answer 6

1. Free living

2. Parasitic

Question 7

What are the 2 ways flatworms feed?

Answer 7

aquatic, free living heterotrophs

1. Carnivores
2. Scavengers

AND

Parasitic heterotrophs

Question 8

What are 3 things the digestive system of a free-living flatworm consists of?

Answer 8

Pharynx
gastrovascular cavity
mouth

Question 9

What is a Pharynx?

Answer 9

muscular tube

Question 10

What is a gastrovascular cavity?

Answer 10

forms an intestine with many branches

Question 11

What does the intestine do?

Answer 11

enzymes help break down food into smaller particles

Question 12

How is digested food transported throughout the body of a flatworm?

Answer 12

diffusion

Question 13

Where do flatworms expel undigested material?

Answer 13

through the mouth

Question 14

What do parasitic flatworms feed on?

Answer 14

blood
tissue
fluids
pieces of cells inside host’s body

Question 15

What is the digestive tract of a parasite flatworm look like?

Answer 15

1. simpler digestive tract compared to free-living earthworms
2. Some DO NOT have digestive tract at all

Question 16

What do parasitic flatworms have?

Answer 16

hooks and/or suckers to attach to intestinal wall of hosts

Question 17

What type of food does parasitic flatworms absorb?

Answer 17

absorb food that has already been broken down by the host

Question 18

Flatworms have no specialized _______ or ________

Answer 18

circulatory or respiratory systems

Question 19

What do flatworms depend on to transport oxygen and nutrients to tissues?

Answer 19

diffusion

Question 20

What do flatworms depend on to get rid of carbon dioxide and metabolic waste?

Answer 20

depend on diffusion

Question 21

What do freshwater flatworms have and what does it do?

Answer 21

have flame cells
assist in removal of excess water

(flame cells join to form network that empties through tiny pores in animal’s skin)

Question 22

What does the nervous system of freshwater flatworms contain?

Answer 22

• simple brain
• 1 or 2 more nerve chords, run through length of body
• ocelli, eyespots
• specialized cells (sensitive to chemicals and water flow)

Question 23

What does the nervous system of parasitic flatworms contain?

Answer 23

nervous system limited or absent

Question 24

What are the 2 methods free living flatworms use to move?

Answer 24

1. Cilia on epidermal cells help them glide through the water
2. muscle cells allow them to twist and turn

Question 25

How do free living flatworms reproduce?

Answer 25

asexually and sexually

Question 26

How do parasitic flatworms reproduce?

Answer 26

only sexually

Question 27

How does asexual reproduction happen in flatworms?

Answer 27

through fission

Question 28

How does sexual reproduction happen in flatworms?

Answer 28

most are hermaphrodites
worms join in pairs
sperm is transferred