16. Vertebrate Diversity - Chordates Flashcards
what are the four features all chordates have?
a notochord
dorsal hollow nerve cord
pharyngeal gill slits
post anal tail
what are the three subphylums of chordates?
vertabrates
cephalochordates
urochordates
what is a notocord? what is its function?
a longitudinal, flexible rod located between the digestive tube and the nerve cord.
composed of large fluid cells that provides skeletal support
what is a dorsal hollow nerve cord?
develops into the central nervous system (brain and spinal cord)
what are pharyngeal slits?
allow watering entering the mouth to exit the body without passing through the entire digestive tract. extends from the mouth to the anus. supports feeding and gas exchange
what is the post anal tail?
a tail that extends the posterior to the anus
what is the deepest branching lineage of chordates?
urochordata (tunicates) in their larval stages represent chordata (image on the right below)
what is special about tunicates?
they are chordates in the frist few minutes of their life then go through metamorphose to an adult
what subphylum are lanclets apart of? what is an important feature of the way they live?
cephalochordata. they live with their posterior end burried in the sand and anterior end for feeding exposed
what subphylum are tunicates apart of?
urochordata
what is the main difference in life stages in lanclets (cephalochordata) and tunicates (urochordata)? two things.
what do they both have in common?
tunicates only resmeblem chordates in larval stages
lanclets retain chordate features as an adult
both suspension feeders
what is neotomy?
the theory of why chordate charcteristics appear at different stages in the life cycle in different species. juvennile characteristics in an adult animals
