ADL Quiz 4

Echinodermata + Chordata

Protostome vs. Deuterostome

Protostome:

• blastopore becomes mouth

• schizocoelous coelom formation

Deuterostome:

• Blastopore becomes anus

• enterocoelous coelom formation

Echinodermata symmetry

pentaradial, some juveniles are bilateral

Madreporite

entrance for water into the water vascular system

• location is major defining feature of each class

Ring canal

central canal where all canals branch from

Tube feet

used for locomotion and prey capture

Ampullae

“balloon” that fills with water causing the foot with a suction cup to extend and stick to the ground/prey

Crinoidea

“form of lily”

• sea lilies/feather stars

• mouth and anus on oral surface

• madreporite is absent (uses coelomic fluid)

• filter feeders

• feathery pinnules on branched arms

• cirri: used to attach to floor/walk

Ophiuroidea

“form of snake tail”

• brittle/basket stars

• madreporite on oral surface

• calcareous shield on aboral surface

• tube feet lack suckers (not for locomotion)

• have INCOMPLETE gut

• arms are distinct from central disc

• no ambulacral groove on arm

Echinoidea

“form of hedgehog”

• sea urchins and sand dollars

• madreporite on anus and aboral surface

• spherical or disc body

• endoskeleton plates fuse to form test

• well developed spines

• feed using aristotle’s lantern

Aristotle’s lantern

echinoidea

• helps scrape algae from surface

Holothuroidea

“form of sedentary marine animal”

• sea cucumbers

• madreporite is internal (in coelom)

• cylindrical body without arms

• detritovores

• have tentacles surrounding the mouth

• use internal respiratory tree

Asteroidea

“form of star”

• sea stars

• madreporite and anus on aboral surface

• tube feet with suckers

• arms are indistinct from the central disc

• have ambulacral groove on arms

• carnivores: pyloric and cardiac stomach

Chordata 4 main characteristics

1. dorsal hollow nerve cord

2. notochord

3. pharyngeal gill slits

4. post-anal tail

• all chordates show these characteristics at some point during embryonic development

Urochordata

“tail cord”

• tunicates/sea squirts

• larvae = free swimming, adults = sessile

• only chordate to have open circulatory system

Cephalocordata

“head cord”

• lancelets

• first group to have dorsal/ventral aorta and myomeres

• small burrowing filter feeders

Craniata

“skull”

• braincase

• complex sensory organs

• heart, hemoglobin, muscular gut

Myxini

“slime fish”

• hagfishes/slime hags

• jawless, no vertebral column

• mostly scavengers

• excrete mucus when threatened

Vertebrata

“joint of the spine”

• vertebrae

• 2 or more semicircular ear canal

petromyzontida

“stone suckle”

• lampreys

• cartilage (arcualia), no true bony vertebrae

• jawless, horned toothlike structures

• can pump water directly in/out of 7 gill cavities

Gnathostomata

“jaw mouth”

• jawed chordates (chondrichthyes + osteichthyes)

Chondrichthyes

“cartilage fish”

• sharks, skates, rays, chimaeras

• cartilaginous fishes

• 5 gill slits

• internal fertilization

• placoid scales made of dentin\

• spiracle behind eye

Chondrichthyan special structures and senses

Ampullae of Lorenzini": electroreception

Lateral line: detects movement, vibration, and pressure

Oviparous

Egg laying

Ovoviviparous

live-bearing but young are fed via a yolk sac

viviparous

live-bearing with young fed via placental nourishment

Osteichthyes

“bone fish”

• heavily ossified skeleton

• lepidotrichia (bony fin elements)

• swim bladder and gills similar to lungs in terrestrial group

Actinopterygii

“ray wings/fins”

• gills covered by bony operculum

• scales made of dermal bone

• lateral line

Heterocercal caudal fin

Vertebra extend into upper lobe making it longer (Chondrichthyes &

sturgeon)

Homocercal caudal tail

Vertebra terminate just after caudal peduncle