Deuterostomes (coelomates = second mouth)

Phylum Echinodermata Sea stars Sea stars brittle stars brittle stars Sand dollars Sand dollars Sea cucmbers Sea cucmbers Sea urchins Sea urchins Feather stars Feather stars

Echinoderm Ancestral Traits Coelom Coelom Bilaterally symmetrical larvae Bilaterally symmetrical larvae –But all adults have radial symmetry Complete digestive system Complete digestive system –(alimentary canal)

Retro traits : bringing back the past Regeneration ability Regeneration ability Radial symmetry: works great for sessile Radial symmetry: works great for sessile –Seems to work for slow moving creatures too –Only larvae still bilateral (evidence of a bilateral ancestor) No head or brain No head or brain –Sensory receptors and nerves spread out in a network around the body No respiratory, circulatory or excretory system No respiratory, circulatory or excretory system –Diffusion through tube feet

Echinoderm Derived Traits Endoskeleton of hard spiny plates Endoskeleton of hard spiny plates –Covered by thin layer of epidermis Tube feet (100s of suction cup feet) Tube feet (100s of suction cup feet)

Sea Star Feeding Sea star pulls a bivalve open using its tube feet Sea star pulls a bivalve open using its tube feet Sea star everts its stomach into the bivalve shell and digests the meat inside Sea star everts its stomach into the bivalve shell and digests the meat inside Stomach returns to interior of sea star Stomach returns to interior of sea star

Phylum Chordata All are deuterostome coelomates All are deuterostome coelomates All have bilateral symmetry at some stage of their life All have bilateral symmetry at some stage of their life

4 key Chordate Characteristics Dorsal hollow nerve cord Dorsal hollow nerve cord A notochord (skeletal rod) supports the nerve cord at some point in development A notochord (skeletal rod) supports the nerve cord at some point in development Pharyngeal pouches at some point Pharyngeal pouches at some point Post anal tail at some point Post anal tail at some point

Phylum Chordata has 3 subphyla 1) Subphylum Urochordata – tunicates (sea squirt) 2) Subphylum Cephalochrodata – lancelets 3) Subphylum Craniata – Superclass : Agnatha – jawless fish Superclass : Agnatha – jawless fish 2 extant classes: hagfish & lamprey 2 extant classes: hagfish & lamprey Superclass: Gnathostomata – jaw mouth Superclass: Gnathostomata – jaw mouth classes: chondrichthyes, osteichthyes, Amphibia, Reptilia, Aves, Mammalia classes: chondrichthyes, osteichthyes, Amphibia, Reptilia, Aves, Mammalia

Tunicates - Subphylum Urochordata Only larvae have chordate characteristics Only larvae have chordate characteristics and muscle segments called myomeres and muscle segments called myomeres Adults sessile filter feeders Adults sessile filter feeders

Tunicates = sea squirts

Subphylum Cephalochordata Lancelets Lancelets Segmented muscles called Segmented muscles called Myomeres Myomeres ‘Head chord’ notochord extends far forward ‘Head chord’ notochord extends far forward Tiny filter feeders Tiny filter feeders

Subphylum Craniata All have cartilagenous /bone endoskeleton All have cartilagenous /bone endoskeleton Covers at least the brain (Craniata) Covers at least the brain (Craniata) Most have vertebrae to protect the dorsal nerve cord Most have vertebrae to protect the dorsal nerve cord (only the hagfish do not) (only the hagfish do not)

Primitive Craniates= Superclass Agnatha (jawless fish) (jawless fish) Hagfish Hagfish Lampreys Lampreys Ostracoderms Ostracoderms –(extinct silurian fish) –Armor plated

Superclass Gnathostomata Jaw mouth = all have jaws Jaw mouth = all have jaws Jaws evolved from gill arches Jaws evolved from gill arches Advantage: break shells/armor/exoskeletons, bite off pieces Advantage: break shells/armor/exoskeletons, bite off pieces Includes All other fish Includes All other fish (not hagfish or lamprey) (not hagfish or lamprey) All tetrapods (gnathostomes that have limbs) All tetrapods (gnathostomes that have limbs)

Class Chondrichthyes Cartilagenous Fish Cartilagenous Fish Sharks Sharks Skates Skates Rays Rays Traits Traits –No swim bladder –No operculum (must swim to breath)

Class Osteichthyes – bony fish Have bone skeleton Have bone skeleton Most have swim bladder Most have swim bladder Have operculum over gills Have operculum over gills

Counter current exchange in gills Closed circulatory system Closed circulatory system Low O2 blood near lowest O2 water Low O2 blood near lowest O2 water Maintains concentrations gradient Maintains concentrations gradient

Lobe-finned fish developed supportive fins & simple lungs from swim bladder

Class Amphibia = first Vert. on land Eggs & larvae in water Eggs & larvae in water Larval respiration gills/skin Larval respiration gills/skin Larval circulatory system like Larval circulatory system like a fish 2 chambered heart 2 chambered heart single loop circulatory system single loop circulatory system

Adults move onto land Stronger skeletal system (no buoyancy) Stronger skeletal system (no buoyancy) Respiration by lungs/skin Respiration by lungs/skin New type of circulatory system New type of circulatory system – 3 chamber heart –2 loop circulatory system –Faster, more efficient Evolutionary Advantage to land Evolutionary Advantage to land –No predators –Insects for food

Class Reptilia Amniote egg = freedom from water Amniote egg = freedom from water Extraembryonic membranes amnion, chorion Extraembryonic membranes amnion, chorion Shelled egg = internal fertilization Shelled egg = internal fertilization Scales = prevent dehydration Scales = prevent dehydration no O 2 from diffusion any longer no O 2 from diffusion any longer Lungs developed folds and pouches Lungs developed folds and pouches –Increased surface area Heart begins to divide into 4 chambers in crocodilians Heart begins to divide into 4 chambers in crocodilians

Class Aves = Birds Amniote eggs Amniote eggs Feathers & scales Feathers & scales Flight: light bones, flight feathers, Flight: light bones, flight feathers, Endothermic: high metabolism=high energy Endothermic: high metabolism=high energy Lungs with air pockets – always fresh air Lungs with air pockets – always fresh air 4 chambered heart – no mixing of oxygenated and un-oxygenated blood 4 chambered heart – no mixing of oxygenated and un-oxygenated blood

Counter current exchange in lung

Class Mammalia Fur/hair & subcutaneous fat Fur/hair & subcutaneous fat Endothermic Endothermic Produce milk (mammary glands) Produce milk (mammary glands) All have amniotic membrane but not all are contained in an egg All have amniotic membrane but not all are contained in an egg

Mammal Amniotes Amniotes of 3 types Amniotes of 3 types –Monotremes lay eggs –Marsupials babies are born as immature embryos and finish development in pouch –Placental mammals embryos obtain nutrients from their mother through a placenta. Offspring are much more mature when born

Amnion membranes

Amniote shared derived traits Dry skin prevents water loss Dry skin prevents water loss Improved Lung & ventilating rib cage Improved Lung & ventilating rib cage Legs elevate body Legs elevate body Kidney remove waste while conserving H 2 O Kidney remove waste while conserving H 2 O Internal fertilization Internal fertilization Amnionic egg with 4 membranes + shell Amnionic egg with 4 membranes + shell –Keeps egg moist but allows gas exchange –Some mammals no longer have shelled egg

Amniotes diverged quickly 1) synapsids evolved into therapsids and then into mammals 1) synapsids evolved into therapsids and then into mammals 2) Sauropsids evolved into Diapsids which then branched into reptiles, dinosaurs and birds 2) Sauropsids evolved into Diapsids which then branched into reptiles, dinosaurs and birds