Midterm 1 Flashcards
(156 cards)
what is the difference between a homocercal tail and a heterocercal tail?
hetero–> two asymmetrical lobes
homo–> equal lobes (produces forward thrust without lift)
Organisms belonging to the phylum Chordata all have what 5 traits at some stage in their life?
- notochord
- pharyngeal gill slit
- subpharyngeal organ (endostyle or thyroid gland)
- a dorsal tubular nerve cord (hollow)
- postanal tail
what is a notochord?
hyrdostatic organ that does not compress, supports the body
what are pharyngeal slits?
- aided in feeding & respiration primitive chordates
- part of the digestive tract
where are the pharyngeal slits?
posterior to the mouth
what is the postanal tail?
posterior elongation of body past the anus
what is the endostyle?
involved in iodine metabolism
- needed to make thyroid hormones
what three things have endostyles?
- urochordates
- cephalochordates
- larval lamprey
what have thyroid glands?
adult lamprey and all other vertebrates
what do chordates include?
all vertbrates along with some primitive sea animals
what do hemichordata have?
- pharyngeal slits
- dorsal nerve chord
what do hemichordates lack?
- post anal tail
- notochord
class ascidiacea
- sac-shaped, enclosed in tunic as adult
- incurrent/excurrent siphon to capture food particles
cephalochrodata
-worm like filter feeders (cilia aid)
- free swimming
-dorsal nerve chord
- pharyngeal gill slits
urochordata
- dorsal nerve chord
- pharyngeal gill slits
-post anal tail - notochord
- filter feeders (cilia aid)
- free swimming
- only larvae
- adults sessile
- adults have a heart no blood vessels
chordata
- dorsal nerve chord
- pharyngeal gill slits
- post anal tail
- notochord
- filter feeder (cilia)
- sexes are separate
-segmented muscle - no heart but blood vessels
evolutionary systematics
places organisms in a common category based on similarities in characteristics
radial (body symmetry)
- body laid out equally from a central axis
- any plane through center divides organism into equal (mirror) parts–> jelly fish
bilateral (body symmetry)
- midsaggital plane divides body into equal parts
frontal plane
bilateral body into dorsal and ventral
saggital plane
bilateral body into left and right
transverse plane
bilateral body into anterior & posterior
anterior
cranial/head
posterior
caudal/tail