Comparative Va

COMPARATIVE VERTEBRATE ANATOMY
-study of the structure(descriptive morphology) and of the functional significance of structure(fumctional morphology) of the vertebrate

Ontogenesis- development of the invidual
Phylogenesis-ancestral history; is is a study of history and of animals that no longer inhabit the earh and known to us by a fossil record
*Craniates- hagfish and vertebrates

THE PHYLUM CHORDATA: THE BIG FOUR
It is falling into two categories:
a. lacks vertebral columns (invertebrates)
b.with vertebral columns(vertebrates)

Protochordates- a dichotomy which is composed of marine animals which is not midway invertebrates and vertebrates
-they do not have vertebral column but they share vertebrate characteristics, the four morphological features

Four Morphological Features:
a. notochord
b. dorsal hollow CNS
c. postanal tail
d. endostyle- glandular groove in the floor of the pharynx
*these features are the first ones who appears in an embryo
*without these features, an embryo cannot proceed to development but the postanal tail is less critical to development
TAXONOMIC RELATION OF THE PROTOCHORDATES AND VERTEBRATES:
Kingdom Animalia Phylum Chordata Subphylum Urochordata Subphylum Cephalochordata Subphylum Craniata Hagfish(w/o vertebrates) Vertebrates(with vertebrates)

Chordates- animals with notochord at their embryo stage at least
Craniates- chordates with a neurocranium(braincase)
Vertebrates- chordates with vertebrae
*Vertebrae appear during embryonic development after the notochord has formed. They may reinforce the notochord or replace it functionally.

THE CRANIATE BODY: GENERAL PLAN
-general pattern of primitive(plesiomorphic) and unique(derived) anatomical features.
-exhibit similar but not identical patterns of embryonic development as a result of common ancestry
-altering the morphology and developmental processes provides