Phyla Hemicordata and Chordata BIO 2215 Oklahoma City Community College Dennis Anderson

Fig. 23.2b

Phylum Hemichordata Three body regions Deuterostome Gill slits Proboscis Collar Trunk Deuterostome Gill slits Open circulatory system Dorsal and ventral nerve cord

Fig. 22.29a

Fig. 22.29b

Chordates Fig. 23.2a

Phylum Chordata Fig. 23.1

Phylum Chordata Notochord Gill slits or pharyngeal pouches Dorsal hollow nerve cord Postanal tail Segmented muscles Deuterostome

Fig. 23.p469a

Fig. 23.p469b

Fig. 23.p472a

Fig. 23.p472c

Evolutionary Adaptations of Chordates From filter feeding ancestors to active predators Mobility Oxygen capture Digestion Circulation Nervous system

Skeletal Changes Skeleton becomes stronger to work with bigger muscles Allows more rapid movement Fig. 23.p477

Oxygen Capture Gill slit and muscular pharynx will move more water over gills More oxygen is extracted from water Fig. 23.p478a

Circulation Stronger heart to circulate blood faster Fig. 23.p478a

Digestion Digest more food Muscularized gut Digestive glands Liver Pancreas Fig. 23.p478a

Nervous System More complex for better Motor control of body to capture food Sensory detection of the animals environment Integration centers (brain) Fig. 23.p478b

Brain With Three Parts Hindbrain Midbrain Forebrain Fig. 23.14

Chordate Subphyla Subphylum. Urochordata Subphylum. Cephalochordata Phylum. Chordata Subphylum. Urochordata Subphylum. Cephalochordata Subphylum. Vertebrata

Sea Squirts

Subphylum Urochordata Sea squirts Gill slits (pharyngeal slits) Notochord Only in larva Adult has tunic

Fig. 23.5

Fig. 23.7

Amphioxus Fig. 23.CO

Subphylum Cephalochordata Amphioxus Notochord length of body Dorsal hollow nerve cord Gill slits Segmented muscles

Amphioxus

The End