Bilateria

Question 1

Characteristics (3)

Answer 1

Bilateral symmetry
Triploblastic: ectoderm, endoderm & mesoderm
Hox genes: encode positional identity along the A-P axis

Question 2

Functions of Internal Compartments (5)

Answer 2

Digestion
Transport of Nutrients & Gases
Hydrostatic Skeleton
Source/storage of gametes
Role in excretion of osmoregulation

Question 3

Fate of the mesoderm?

Answer 3

Secondary body compartments (acoelomate, psuedocoelomate and eucoelomate)

Question 4

Deuterostomia vs Protostomia (4)

Answer 4

Deuterostomia: Radial cleavage, mesoderm arises from endoderm, eucoelom arises from enterocoely, blastopore forms anus
Protostomia: Spiral cleavage, mesoderm arises from mesentoblast, eucoelom arises from schizocoely, blastopore forms mouth or anus

Question 5

Entercoely vs Schizocoely

Answer 5

Entercoely: Coelomic pouches form from the budding of the archenteron
Schizocoely: Coelomic pouches form from splitting of mesoderm

Question 6

Bilateria Phylogeny

Answer 6

Deuterostomia: Echinodermata, Hemichordata and Chordata
Protostomia: Lophotrochozoa (Annelida, Mollusca, Platyhelminthes) and Ecdysozoa (Arthropoda and Nematoda)