BSC 201: Exam 2

Eumetazoan

true animals with differentitiaed tissues

contains radiata and bilateria

Metazoa

the most basal grouping og animals

CHoanoflagellates are NOT are common ancestor arguments

• Choanocytes are not part of the developmental pathway of sponges; they appear only in adult sponges

• collar cells appear in a few othr animal taxa; if trait is ancestral it has been lost in most taxa

Evidence of common ancestry between choanoflagellates and metazoa

• proteins used by colonial choanoflagellates for cell communication and adhesion are homologous to those that metazoans use in cell-to-cell signaling

Lophotrotrohoza

bilterian protostomia

Ecdysozoa

bilterial protostomia that goes through ecydsis

Phylum Porifera

basal animals that lack true tissues

• no symmetry

• no nerves, muscles, mouth or digestive system

sessile

reproduce sexually and asexualyl

Asconoid

porifera body plan, where choanocytes line the inside of the spongocoel

water enters through the ostium, which are liend with proocytes

only occurs in class Calcarea

Syconoid

porifera body plan

tubular body wall with a single osculum

body wall forms radial canals that is lined with choanocytes

water enters through the ostia into the choanocytes, where it is pushes through the apopyle and into the spongocoel

may be found in class Calcarea or Hexactinellida

Leuconoid

Porifera body plan

most complex body plan w/ the highest surface area

contains chambers with choanocytes

water enters through the ostium and is pumped through an incurrent canal and into a flagellated chamber. Water is then pushed to the excurrent canal and out many osculum

most common between classes, exlusive in Demospongiae

Archaeocytes

amoeboid cells found in sponge that can transfrom into any of the animal;s more specalized cell types

Pinacocytes

flat cells the line on the outside of a sponge, as well as the internal canals of a sponge