Biology Unit 8: Echinodermata & Chordata (Fishes)

Branchos

Gill

Ampulla

Flask

Pyloros

Gatekeeper

Cardio

Heart

Caecus

Blind

Aster

Star

Ura

Tail

Gnathos

Jaw

Brachium

Arm

Phyo

Produce, grow, make

Ganotos

Polished, brightened 

Cyclo

Circle

Chondro

Cartilage

Actino

Ray

Sarcos

Flesh

Pteryx

Fin, wing

Ichthys

Fish

Characteristics of echinoderms

Water-vascular system, Unsegmented body, with pentaradial symmetry (can be divided into five equal parts), No brain, Respiration by papulae, No excretory organs

Class Crinoidea

Name meaning: Lily-like/form

Ex: Feather star 

Description: Marine invertebrate related to starfish and sea urchins. Filter feeders using their mucus cover tube feet to trap food particles.

Class Asteroids

Name meaning: Star form

Ex: Sea star/ Starfish 

Description: Feed on mussels, can push their stomach out of their mouth to digest food, tube feet powered by water pressure

Class Ophiuroidea

Name meaning: Snake tail

Ex: Brittle stars  

Description: Most active, bend arms instead of using tube feet

Class Echinoidea 

Name meaning: Spiny

Ex: Sea urchins   

Description: Radially symmetrical, feed on small particles, prefers hard substrates

Class Holothuroidea

Name meaning: whole rushing

Ex: Sea cucumbers  

Description: Soft, Deposit feeders

External features

Central disc that merges with the rays. Flattened, flexible body covered in cilia with a pigmented epidermis. 

Endoskeleton

Ossicles bound together by connective tissue. Catch collagen (mutable collagen). Collagen can change from liquid to solid. Stereom.

Coelom

Fluid-filled ambeocytes (Coelomocytes). Papulae

Excretion

Lacks organs like kidneys. Excretes through diffusion to get rid of nitrogenous waste.

Respiratory 

Lacks oragns, breathes with a process called diffusion (tube feet). 

Water-vascular system: madreporite

Outside small pore opening. Filters water from surrounding.