Ancestral deuterostome has 2 phylum:
I. Echinodermata – doesn’t have 4 chordate characteristics
II. Chordata - have 4 chordate characteristics (not always every stage in life)
i. Notochord
ii. Dorsal, hollow nerve cord
iii. Pharyngeal slits
iv. Muscular, post anal tail
Chordata:
1. Invertebrates
- 4 characteristics, NO VERTEBRAL COLUMN
- Cephalochordata, Unichordata
2. Vertebrates
- 4 characteristics, ALL HAVE VERTEBRAL COLUMN
- 3 derived features shared by vertebrates
i. Neural crest
ii. More extensive muscular system
iii. High metabolic rate
- Classified more by extra additions
1. Vertebral column only, NO JAW
o Called Cyclostomes and agnathans (jawless)
o 1st vertebrates in Cambrian explosion
o No bones (mineralization) – teeth/vertebrae are cartilage
o 2 groups:
1) Myxini - hagfishes
- Scavengers
- Notochord very basic, for support
- Marine
- Bottom dwelling scavengers
- Nutrition – have rows of slime glands that secrete substance
- Substance absorbs water and repulses other scavengers while feeding
- Have head and skull made of cartilage
- Small brain
- Sensory organs
- Tooth-like structures
2) Petromyzontida - lampreys
- Parasitic or flesh eating
- Notochord surrounded by protective sheath
- Marine and freshwater
- Nutrition – use rasping tongue to penetrate fish skin and suck blood
- Mostly parasites
- Don’t have:
- head and skull made of cartilage
I. Echinodermata – doesn’t have 4 chordate characteristics
II. Chordata - have 4 chordate characteristics (not always every stage in life)
i. Notochord
ii. Dorsal, hollow nerve cord
iii. Pharyngeal slits
iv. Muscular, post anal tail
Chordata:
1. Invertebrates
- 4 characteristics, NO VERTEBRAL COLUMN
- Cephalochordata, Unichordata
2. Vertebrates
- 4 characteristics, ALL HAVE VERTEBRAL COLUMN
- 3 derived features shared by vertebrates
i. Neural crest
ii. More extensive muscular system
iii. High metabolic rate
- Classified more by extra additions
1. Vertebral column only, NO JAW
o Called Cyclostomes and agnathans (jawless)
o 1st vertebrates in Cambrian explosion
o No bones (mineralization) – teeth/vertebrae are cartilage
o 2 groups:
1) Myxini - hagfishes
- Scavengers
- Notochord very basic, for support
- Marine
- Bottom dwelling scavengers
- Nutrition – have rows of slime glands that secrete substance
- Substance absorbs water and repulses other scavengers while feeding
- Have head and skull made of cartilage
- Small brain
- Sensory organs
- Tooth-like structures
2) Petromyzontida - lampreys
- Parasitic or flesh eating
- Notochord surrounded by protective sheath
- Marine and freshwater
- Nutrition – use rasping tongue to penetrate fish skin and suck blood
- Mostly parasites
- Don’t have:
- head and skull made of cartilage
