Phylum Chordata Flashcards
where is the dorsal tubular nerve chord present
above the notochord and below the dorsal body wall
is the dorsal nerve chord ganglionated or non ganglionated
non ganglionated
how is the dorsal nerve chord produced?
by the sinking in of median dorsal strip of ectoderm
a distinct brain at the anterior end can be seen in?
higher chordates
the rest of the dorsal nerve chord becomes?
spinal chord
what are pharyngeal slits?
a series of lateral perforations on the wall of pharynx thru which water flows out of pharyngeal cavity
they are ectodermal in nature true or false
true
these slits are present thru out life in?
protochordates ,fishes and some amphibians
walls of pharyngeal slits develops into vascular lamella to form?
gills (branchia)
the gills help in?
exchange of gases
in what stage of life are gills present in amphibians?
in larval stages
are gills persistent thru out life in amphibians?
No,they are absent in adult forms of amphibians
non functional pharyngeal pouches appear in ?
Amniotes
when do these pouches appear in amniotes?
In early embryonic stage
are the pouches persistent thru out life?
No they disappear later
occurrence of such pouches of amniotes provides a clue to their?
Aquatic ancenstory
post anal tail contains?
skeletal elements and muscles
what are absent in post anal tail ?
visceral organs and coelom
function of post anal tail in aquatic species
locomotion
function of post anal tail in few terrestrial animals
provides balance (kangaroo)
name 9 chordate characters
Bilateral symmetry,triploblastic,organ system level of organization and metamerism,cephalization,enterocoelom,complete digestive tract,closed type of circulatory system,ventral myogenic heart (except in lancelets)
how many sub phyla does phylum choradata include
3 (urochordata,cephalocordata,vertebrata)
urochordates and cephalochordates together are referred as
Protochordates
sub phyla urochordata is also called as
Tunicata
