Arthropods, Echinoderms, and Chordates

Objectives

• Summarize traits of echinoderm invertebrates
• Identify the nine classes of vertebrates
• Outline the characteristics of chordates
• Overview the five living classes of fish

Arthropod Conclusion

• Sexual reproduction
• Oldest arthropods were trilobites
• Arthropods were first animals to live on land

Echinoderms

Echinoderms

• Marine animals
• Endoskeleton of CaCO3
• Adults have radial symmetry
• Water vascular system
• Tube feet

Echinoderms

• Tube feet allow diffusion of waste
• No respiratory or excretory systems
• No central nervous system
• Open circulatory system
• Coelom and complete digestive system

Echinoderms

• Pheromones to communicate
• Simple eyes (ocelli)
• Can regenerate body parts

Chordates

Chordate Characteristics

• Post-anal tail
• Dorsal hollow nerve cord
• Notochord (provides stiffness)
• Pharyngeal slits

Living Chordate Subphyla

• Vertebrata
• Urochordata
• Cephalochordata

Vertebrate Classes

Vertebrate Classes

• Amphibians
• Reptiles
• Birds
• Mammals

Vertebrate Classes cont.

• Hagfish
• Lampreys
• Cartilaginous fish - shark
• Ray-finned fish - perch
• Lobe-finned fish - coelacanth

Fish Classification

Hagfish

• Primitive
• Retain notochord
• Lack scales and fins
• Have cranium
• Secrete thick, slimy mucus

Lampreys

• Also lack scales
• Have fins and partial backbone
• Large, round sucker lined with teeth

Cartilaginous Fish

• Sharks, rays, and ratfish
• Cartilage plus complete backbone
• Relatively large brain
• Lack a swim bladder
• Jaws an important adaptation

Ray-finned Fish

• Majority of living fish species
• Bony endoskeleton
• Swim bladder
• Fins lack muscle

Lobe-finned Fish

• Fins contain bone and muscle
• Coelecanth and lungfish