Deuterostomes

Echinoderms

no head
-oral & aboral sides
-internal skeleton of calcified internal plates
-water vascular system leading to tube feet

starfish

Chordate synapomorphies

dorsal, hollow nerve cord
-post-anal tail
-pharyngeal slits
-notochord
*large cells with fluid-filled vacuoles
*rigid but flexible
*lost in urochordates
*skeletal parts in vertebrates

Urochordates (sea squirts) and Cephalochordates

are marine

lack a spinal column but have a norochord

Vertebrates

skeleton with vertebral column
-anterior skull
-internal organs
-circulatory system

-jaws

Chondrychthyans

skeleton of cartilage
-most are marine, predatory

(sharks, skates, rays)

Ray-finned fishes

skeleton of calcified bone
-scales
-radiated during Cenozoic (<65 mya)
-diverse forms, life histories

Jointed fins were an innovation in the
ancestor of the

sarcopterygians

Tiktaalik

transitional fossil
-fresh water fish
-neck, wrist bones

Amphibians adapted to life on land

mmost in moist environments
-metamorphosis
-complex social behaviors
-declining populations

Amniote egg permited colonization of dry
environments

shell permits gas exchange, minimizes water
loss; yolk provides nutrients

other aminote innovations

covered skin
-excretory organs

Crocodilians and birds share ancestor with
dinosaurs

Birds > half of living reptiles (therapods)
Feathers (modified scales) allowed flight
Fossils, anatomy

Mammals

sweat glands
-mammary glands
-hair
-four-chambered heart (archosaurs)

Prototherians (platypus & echidnas)

eggs, lack placenta, lack nipples

Marsupials

Eutherians (placental mammals)

gestation, pouches

-offspring development
-adaptive radiation

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Primates

small, arboreal, insectivorous ancestor
-grasping limbs, opposable digits
-two clades: Prosimians and Anthropoids