graptolites Flashcards
graptolite PHYLUM
hemichordata
graptolite CLASS
graptolithinia
graptolite NEMA
thin tube extendinsion of the siclua
what is the possible function of the nema in a graptolite
attachment to floating object
graptolite STIPE
branch of the rhabdosome
graptolite THECA
indivicula cup in which ONE zooid lived
were graptolites colonial or solitary
colonial
graptoloid what was skkeletion made of
scleroprotein skeleton
graptoloid SICULA
conical tube secreted by thhe first member of the colony
graptoloid VIRGELLA
spine at the end of the sicula
graptoloid APERTURE
part where the zooid protruded through the skeleton in order to filter feed
PLANKTONIC graptolite where did it live?
water column
what way up was graptolite
appeture of sicula faced downwards
did graptolite attach to anything/.
nema attaced to floating objects + FACED UPWARDS
HOW DID graptolites feed
spiral down through water column filter feeding
graptolite importance as a ZONE FOSSIL
rapid evolution
abudnece
planktonic lifestyle
USED TO ZONE ORDOVICIAN AND SILURIAN
graptolite range
Ordovician - abundant in Silurian - extinct in devonian
How did the number of stipes change over time in GRAPLOTIES
early ones had up to 8 but over time they lost them
How did attitude of stipes in gratolites change over time
they were pendent (downwards facing)
became horizontal
then became scandent (upwards facing)
changes in graplotite THECAE
evolved from simple to complex for more efficient filter feeding
changes in graptolite THECAE ARRANGEMENT
uniserial (thecae on one side of the stipe) to bi serial (both sides) then back to uniserial
eg graptolite with 1 stipe
monograptus (Silurian)
eg graptolite with 4 stipes
tetragraptus (Ordovician)
