Coelomate Animals Have a true coelom, not a pseudocoelom Have a true coelom, not a pseudocoelom True coelom is a hollowed out space inside the mesoderm, not a space between tissue layers True coelom is a hollowed out space inside the mesoderm, not a space between tissue layers Coelom provides space for organs to develop Coelom provides space for organs to develop

2 Groups of Animals have Coeloms Protostomes Protostomes mouth forms first mouth forms first Phylum Mollusca Phylum Mollusca Phylum Annelida Phylum Annelida Phylum Arthropoda Phylum Arthropoda Deuterostomes Deuterostomes anus forms first anus forms first Phylum Echinodermata Phylum Echinodermata Phylum Chordata Phylum Chordata

New Traits of All Coelomates Circulatory systems that pump blood Circulatory systems that pump blood Excretory systems = kidney Excretory systems = kidney Respiratory structures present in most species Respiratory structures present in most species Gills in: - some Mollusks Gills in: - some Mollusks Some Arthropods (Crustaceans) Some Arthropods (Crustaceans) Some Chordates (lamprey, Fish, larval Amphibians) Some Chordates (lamprey, Fish, larval Amphibians) Lungs in: - some Mollusks Lungs in: - some Mollusks Lung fish Lung fish Some Chordates (adult Amphibians, Reptiles, Birds, Mammals) Some Chordates (adult Amphibians, Reptiles, Birds, Mammals) Trachea in: Insects Trachea in: Insects Book lungs in: Arachnids Book lungs in: Arachnids

Phylum Molluska Shell excreted by mantle Shell excreted by mantle Muscular foot Muscular foot Gills or lung (snails) Gills or lung (snails)

Class Bivalvia Name means 2 shells Name means 2 shells Most are filter feeders Most are filter feeders Clams, oysters, mussels, scalops Clams, oysters, mussels, scalops

Class Gastropoda Name means Stomach-Foot Name means Stomach-Foot snails, slugs & nudibranchs (sea slugs) snails, slugs & nudibranchs (sea slugs) some have lungs some have lungs

Class Cephalopoda Name means head-foot Name means head-foot Squids, octopuses, nautiluses, cuttlefish Squids, octopuses, nautiluses, cuttlefish Highly developed brain, human like eye (c. evol) Highly developed brain, human like eye (c. evol) Largest inverts : huge nerve axon = low resistance Largest inverts : huge nerve axon = low resistance

Cephalopod Derived Traits : Adaptations of a Predator Shell filled with chambers of air for buoyancy Shell filled with chambers of air for buoyancy Shells lost or small & internal = less weight Shells lost or small & internal = less weight Closed circulatory system = faster circulation for better delivery of oxygen to muscles Closed circulatory system = faster circulation for better delivery of oxygen to muscles Well developed eyes and brain = must be smarter than the food Well developed eyes and brain = must be smarter than the food Foot converted to tentacles Foot converted to tentacles and siphon (jet propulsion)

Phylum Annelida:Segmented worms Earth worms Earth worms Leeches Leeches Marine Worms Marine Worms Freshwater Freshwater worms worms

Annelid traits Annelid traits Body divided into segments Body divided into segments

Advantages of segmentation… Repeating body parts allows evolution of one segment while another segment maintains original function Repeating body parts allows evolution of one segment while another segment maintains original function

Phylum Arthropoda Subphylum Crustacea Subphylum Crustacea Class Insecta Class Insecta Class Arachnida Class Arachnida Classes Diplopoda/chilopoda Classes Diplopoda/chilopoda

Arthropod Traits Name means jointed-foot Name means jointed-foot Also have jointed legs Also have jointed legs Segmented bodies Segmented bodies Exoskeleton (chiton) Exoskeleton (chiton) Open circulatory system Open circulatory system

Insect Innovations Respiration using tracheae –tubes that branch throughout the body Respiration using tracheae –tubes that branch throughout the body Compound eye Compound eye Wings Wings Complex life cycle Complex life cycle

Arachnids Respiration by book lungs Respiration by book lungs spiders spiders ticks ticks mites mites Scorpions Scorpions harvestmen harvestmen May have silk glands to make web May have silk glands to make web

Crustacea Nearly all aquatic Nearly all aquatic Respiration by gills Respiration by gills Important part of zooplankton Important part of zooplankton