Echinoderms & Chordates

Blastopore

first opening in embryo

Spiral cleavage

twisted cell division

Radial cleavage

symmetrical division

Engrailed

segmentation gene

Distal-less

limb development gene

Orthodenticle

head development gene

Keystone species

species with major ecosystem impact

Pisaster ochraceus

sea star example

Cephalization

concentration of head structures

Notochord

flexible support rod

Amphioxus

primitive chordate

Phylum Echinodermata

sea stars, urchins

Class Crinoidea

sea lilies

Class Asteroidea

sea stars

Class Ophiuroidea

brittle stars

Class Echinoidea

sea urchins

Class Holothuroidea

sea cucumbers

Subphylum Urochordata

tunicates

Subphylum Cephalochordata

lancelets

Subphylum Vertebrata

vertebrates

Protostome vs deuterostome

mouth vs anus develops first

Echinoderm success

regeneration, water vascular system

Keystone importance

maintain ecosystem balance

Chordate features

notochord, dorsal nerve cord, pharyngeal slits

Importance of head

sensory + brain concentration

Fish

gills, fins, scales

Reptiles

dry skin, amniotic egg

Turtles

shell structure

Birds

feathers, flight adaptations

Mammals

hair, mammary glands, endothermy