Lophophorates and chordata Flashcards
what is the lophophore?
- a u-shaped organ made up of 1-2 rows of ciliated tentacles
- used for prey capture and gas exchange
What are the three phyla that possess a lophophore?
- Phoronida
- Brachiopoda
- Bryozoa
What is the Phylum Phoronida?
- a lophophorate
- only 14 species
- hermaphroditic
- they secrete chitinous tube, and reside within that chitinous tube that is embedded into sediment
What is the defining characteristic of Phylum Brachiopoda?
- 2 valved shell oriented dorsally and ventrally
Brachiopods superficially look like…..
bivalve molluscs
what are the two brachiopod classes?
- Articulata
- Inarticulata
How are brachiopods and bivalves different?
- Brachiopods have dorsal and ventral valves, also shell opening caused by muscles
- bivalvia have left and right valves, shell opens by ligament
What are bryozoans?
- moss animals
- colonial and composed of individual zooids
- lophophore can be protruded from zooids ‘house’ to feed and exchange gases
what are the three Bryozoan classes?
- Phylactolaemata
- Gymnolaemata
- Stenolaemata
what are statoblasts?
- resting stage formed by class phylactolaemates that can withstand dessication/thermal stress
- analogous to gemmules from porifera
gymnolaemate bryozoan colonies have……
polymorphic zooids (they can perform specialized functions)
What is Phylum Entoprocta?
- marine organisms
- can be solitary or colonial
- anus lies within the ring of ciliated tentacles used to trap food and exchange gas
what are the defining characteristics of phylum chordata?
- dorsal, hollow nerve chord (tube-like structure, develops into central nervous system)
- notochord (flexible rod- provides skeletal support)
- stigmata (slits in pharynx, function in feeding or respiration)
- post-anal tail (tail posterior to the anus)
all invertebrate chordates are…
marine
what are the two subphyla from chordata?
- tunicata
- cephalochordata
what are the defining characteristics of subphylum tunicata?
- notochord and nerve chord only in larva
what are the three major tunicata classes?
- ascidiacea
- larvacea
- thaliacea
what is class ascidiacea?
- ‘sea squirts’
- sessile as adults, with a protective test called a tunic (nonliving)
- suspension feeders, use the cilia lining the pharynx to create a water current
- mucus is secreted by a gland called an endostyle so water passes through all of it and food particles are captured
- most are simultaneous hermaphrodites
what is class larvacea?
- under subphylum tunicata
- resemble a larvae, possibly due to neoteny (retention of juvinile characters as an adult), or an ancestral trait
- never colonial, suspension feeders
what is class thaliacea?
- under subphylum tunicata
- includes pyrosomes, salps, ect
- mobile as adults but suspension feeders.
- both sexual and asexual repro
what are the defining characteristics under subphylum cephalochordata?
- notochord extends anterior to nerve chord
- notochord is contractile
what are some general characters on subphylum cephalochordata?
- highly mobile
- suspension feeders, with mechanism similar to ascidians
- limited cephalization
