Phylum Platyhelminthes: Flatworms Flashcards
Flatworms have what type of symmetry?
simplest animals with BILATERAL symmetry
Do flatworms have a head?
yes, characterized by cephalization in the anterior end of the organism
How thick is a flatworm?
only a few mm thick
Are bodies of flatworms divided into segments?
no
Flatworms have more developed organs than _______ and _________
cinidarians
poriferans
What are the 2 life forms flatworms occur in?
- Free living
2. Parasitic
What are the 2 ways flatworms feed?
aquatic, free living heterotrophs
- Carnivores
- Scavengers
AND
Parasitic heterotrophs
What are 3 things the digestive system of a free-living flatworm consists of?
Pharynx
gastrovascular cavity
mouth
What is a Pharynx?
muscular tube
What is a gastrovascular cavity?
forms an intestine with many branches
What does the intestine do?
enzymes help break down food into smaller particles
How is digested food transported throughout the body of a flatworm?
diffusion
Where do flatworms expel undigested material?
through the mouth
What do parasitic flatworms feed on?
blood
tissue
fluids
pieces of cells inside host’s body
What is the digestive tract of a parasite flatworm look like?
- simpler digestive tract compared to free-living earthworms
- Some DO NOT have digestive tract at all
What do parasitic flatworms have?
hooks and/or suckers to attach to intestinal wall of hosts
What type of food does parasitic flatworms absorb?
absorb food that has already been broken down by the host
Flatworms have no specialized _______ or ________
circulatory or respiratory systems
What do flatworms depend on to transport oxygen and nutrients to tissues?
diffusion
What do flatworms depend on to get rid of carbon dioxide and metabolic waste?
depend on diffusion
What do freshwater flatworms have and what does it do?
have flame cells
assist in removal of excess water
(flame cells join to form network that empties through tiny pores in animal’s skin)
What does the nervous system of freshwater flatworms contain?
- simple brain
- 1 or 2 more nerve chords, run through length of body
- ocelli, eyespots
- specialized cells (sensitive to chemicals and water flow)
What does the nervous system of parasitic flatworms contain?
nervous system limited or absent
What are the 2 methods free living flatworms use to move?
- Cilia on epidermal cells help them glide through the water
- muscle cells allow them to twist and turn
How do free living flatworms reproduce?
asexually and sexually
How do parasitic flatworms reproduce?
only sexually
How does asexual reproduction happen in flatworms?
through fission
How does sexual reproduction happen in flatworms?
most are hermaphrodites
worms join in pairs
sperm is transferred
