Vertebrates

Chapter 48

I. what is a Phylum Chordata?

a. A deuterosome coelomate most closely related to invert echinoderms.

b. characteristics of a chordate:

i. nerve cord that may become as complex as the central nervous system.

ii. Notocord (flexible rod along dorsal surface deep to nerve cord) may be displaced by vertebral column

iii. Pharyngeal slits/pouches connect respiratory insides to external environment land vertebrate slits/pouches close (humans have one remaing that becomes eustachian tubes)

iv. Postanal tail

c. Other important chordate characteristics

i. Segmented muscles

ii. Most have internal skeleton

d. Invert vs. verts chordata

i. Subphylum urochordata(Invert chordates): sessile marine chordates

ii. Subphylum Vertebrata: (craniate chordates)

1. vertebral column

2. head

3. neural crest: which becomes gills, sensory organs, dorsal root ganglion, tooth development, some cranial bones….etc.

4. organs: closed circulation, specialized excretory system.

5. endoskeleton

II. evolutionary steps to land

a. integumentary sytems :

b. skeletal systems

c. muscular systems

d. nervous systems

e. circulatory systems

f. respiratory systems

g. excretory systems

h. reproductive strategies