lecture 17 Flashcards
(109 cards)
Most animals on earth belong to what clade?
Bilateria
What is a key feature of the Bilateria?
They posses bilateral systemtry
What is cephalization?
differentation of a head region
Are Bilateria cephalization?
They have varrying degrees, including anterior concentartion of neural ganglia ( brain)
What is a neural ganglia?
Brain
What type of embryos do Bilateria posses?
Triploblasic embryos.
are Acoela Bilateria?
Yes they are
What phylum do marine worms reside from?
Acoela
What us unique about Acoela?
They have no brain and they have no gut cavity.
What is a .worm?
General term for an animal with a body that lacks shell or elaborate appendages and usually longer than wide.
Where on the phylogentic tree would Acoela be in relation to the rest of the Bilateria?
Some molecular data places acoela as basal to the rest of the Bilateria
What are the four main characteristic of Lophotrochozoa?
- Some have lophophore
- Some have trochophore larva
- others have neither
- Main similarities are in DNA
How many phyla exist within Lophotrochozoa?
There are roughly 18
what Lophotrochozoa phylum contains flatworms?
Platyhelminthes.
What does the root word “platy” mean?
Flat
What does the root word “helminth” mean?
Worm
Flat worms have no fluid filled body cavity, what is this called?
Acoelomate.
Are flatworms triploblastic?
Yes they are.
How many species of Platyhelminthes are there?
roughly 20,000 spp
What are the two major classes of Platyhelminthes?
Class turbellaria
Class cestoidea
What is unique about the Turbellaria?
They are called the free-living flatworms.
- The epidermis of Turbellaria are covered in epidermal cilia.
Turbellaria have a pair of ___________ and ____________ near the front of their body.
Ventral nerve cords
and
pair of ganglia
Do turbellaria have an anal opening?
Nope
Are Turbellaria predatory?
Yes some are , mostly on other small metazoans.