Flashcards in Diversity of Animals I Deck (266)
What is the phylum name for flatworms?
How many germ layers do platyhelminthes have?
What type of body cavity do platyhelminthes have?
Describe the body cavity of platyhelminthes
Filled with loose parenchyma derived from mesoderm
Describe the symmetry of platyhelminthes
What is a characteristic of the platyhelminthes body shape?
What are three classes of platyhelminthes?
Are turbellaria free-living or parasitic?
What structure do turbellaria use to feed?
A pharynx that comes out of a ventrally-located mouth
Describe the turbellaria diet
Carnivorous: living invertebrates or dead animals
What is an advancement of turbellaria digestive system?
Highly branched to increase surface area
Do platyhelminthes have a complete digestive tract?
No, they do not have an anus.
How does egestion occur for platyhelminthes?
Out of mouth (no anus)
Where does platyhelminthes gas exchange occur?
Diffusion through their skin (aided by being flat)
How does excreton occur for platyhelminthes?
Excretion of NH3 by diffusion
What is a huge advancement of platyhelminthes for water removal?
Water is removed by protonephridia with a flame cell.
Describe the platyhelminthes central nervous system
Transverse nerve cords with a tiny cerebral ganglia at the head of the animal.
How do turbellaria reproduce asexually?
Transverse binary fission into 2 small turbellarians called zooids.
How do turbellaria reproduce sexually? (3 steps)
1. Both flatworms exchange sperm (monoecious)
2. Zygotes are enclosed in a cocoon
3. Zygotes develop into immature turbellarians that break out of the cocoon when the weather is good.
What is a common name for the trematoda?
How do trematodes feed?
Adult flukes are parasitic on vertebrates
Describe the trematoda digestive tract (2 components)
1. Mouth and Pharynx
2. 2 Intestinal branches
Do trematodes have a complete digestive system?
No. No anus
How does a fluke protect itself from the host's defenses and digestive juices?
A layer of the epidermic called the tegument
Is the fluke tegument living or nonliving?
Where does gas exchange occur in a trematode?
Diffusion through epidermis
Where does excretion occur in a trematode?
Diffusion of NH3 through epidermis
How does a fluke attach itself to its host? (2 ways)
1. Oral sucker
2. Acetabulum (ventral sucker)
What species of trematode is the human liver fluke?