Echinoderm General characteristics Flashcards
type of symmetry adults exhibit
5 sided pentaradial symmetry
do they have a skeleton? Where is it located
internal (except in sea urchin)
describe the skeleton of urchins and sand dollars
fused plates which makes them rounded
what type of vascular system
water vascualr
where do the spines protrude from
plates
examples of echinoderms
seastars, brittle stars, sea urchins, sea cucumners
describe the water vascular system
internal network of fluid filled canals connected to tube feet
importance of teh water vascular system
feeding, internal transport, excretion
describe how the water vascular system works
enters through madriporite ->into ring canal -> into tube feet
why does the vascular system work like a hydraulic pump
when water pushes into the tube foot, it expands. when water is pulled out, it contracts.
The side that the mouth is on is called what
oral surface
describe carniverous echinoderms
the sea stars
open shells, expells stomach into shell, excretes enzymes to digest, pulls back stomach
descrieb herbivorous echinoderms
the sea urchens uses jaws (aristotles lantern) to scrape and chew algae
describe the detrivourous echinoderms
sea cucumbers
how do echinoderms respire
diffusion through thin-walled tube feet
some species have gills
describe the circulatory system
not well developed
distribution of nutrients in coelomic cavity
what is the coelomic cavity
part of the water vascular system
how do echinoderms excrete waste
solid waste expelled through tube feet (except in brittle stars)
do echinoderms have a brain
no
what kind of sensory systems do echinoderms have
nerve ring which surrounds mouth
radial nerves that travel down each arm below the vascular canals
sensory cells to detect food (chemical stimuli)
statocysts for balance
ocelli to detect light/dark
how does the reproduction work
ovaries or testies in radial segments (openings between arms)
broadcast fertilization -> stimulated others to release
describe the larvae
free-living, bilaterally symmetrical
part of plankton
importance of echinoderms
controls populations of other animals and algae
research of embryological developement
