(coelomates = second mouth) Deuterostomes (coelomates = second mouth)

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

Echinoderm Deuterostome Traits 1.Coelom 2. mouth forms second 2. Bilaterally symmetrical larvae But all adults have radial symmetry 3. Complete digestive system (alimentary canal)

Retro traits : bringing back the past Regeneration ability 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 Sensory receptors and nerves spread out in a network around the body No respiratory, circulatory or excretory system Diffusion through tube feet

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

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

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

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

Phylum Chordata Superclass : Agnatha – jawless fish 2 classes: hagfish & lamprey Superclass: Gnathostomata – jaw mouth classes: chondrichthyes, osteichthyes, Amphibia, Reptilia, Aves, Mammalia

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

Superclass Gnathostomata Jaw mouth = all have jaws Advantage: break shells/armor/exoskeletons, bite off pieces Includes All other fish (not hagfish or lamprey) All tetrapods (gnathostomes that have 4 limbs)

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

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

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

Class Amphibia = first Vert. on land Fish like traits: 1. Eggs & larvae in water 2. Larval respiration gills/skin 3. Larval circulatory system like a fish 2 chambered heart single loop circulatory system

Class Amphibia 3 Orders of Amphibian 1. frogs/toads 2. salamanders/newts 3. caecilians

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

Class Reptilia Amniote egg = freedom from water Shelled egg = internal fertilization Scales = prevent dehydration no O2 from diffusion any longer Lungs developed folds and pouches Increased surface area Heart begins to divide into 4 chambers in crocodilians

Reptiles….

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

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

Mammal Amniotes 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

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