phylum echinodermata
DESCRIPTION
Phylum Echinodermata. Greek “ echinos ” spiny “derma” skin. 560 million years ago. Cnidarians and Poriferans 2 cell layers no mesoderm no organs Echinoderms 3 cell layers mesoderm= coelomates organs. Main Charcteristics. Radial symmetry: PENTARADIAL - PowerPoint PPT PresentationTRANSCRIPT
Radial symmetry: PENTARADIAL Bilateral in free swimming embryonic
stages
200 arms Comanthina schlegelii
Rare species have 6 arms
endoskeleton made of tiny calcareous plates and spines (OSSICLES)
Acts like exoskeleton but its NOT! always contained within a layer of living tissue
Mutable Connective Tissue (MCT) :has special ability to be converted from stiff to soft in an instant
Hydraulic network of fluid-filled canals Water enters the MADREPORITE Very powerful, but slow
Gas exchange Feeding Locomotion
Bumps and spines let in oxygen Skin is very thin: oxygen can diffuse in
from the surrounding water
No brain Nerve ring surrounding the gut Radial nerves run under the ambulacra Sensory neurons are located primarily
within the ectoderm of podia
External Fertilization Separate sexes Reproductive organs in each arm Some species brood their young
100,000,000 eggs at once
Fission of body parts Regeneration: spines, arms,
intestines
ECHINODERMS
ASTEROIDEA
CRINOIDEA
ECHINOIDEA
HOLOTHUROIDEA
OPHIUROIDEA
1
23 41. CHARACTERISTI
C2. CHARACTERISTI
C3. CHARACTERISTI
C4. SPECIES
A. DESCRIPTIONB. WHERE FOUNDC. COLOR/SHAPE
A
B
C
• Kingdom Animalia•Phylum Echinodermata Class Asteroidea Class Echinoidea Class Holothuroidea Class Ophiuroidea Class Crinoidea
Mostly benthic carnivores Eye spots: end of each arm. Tube feet have suckers, which
chemically adhere to the substrate. Another chemical bond is secreted to release the tube feet.
Keep animal free from encrusting organisms
May contain toxins Protect the papulae: skin gills
Some may use pedicellariae to aid in food capture
Evert stomach and secrete primary enzymes on the prey.
The digestive juices break down the tissue of the prey, which the asteroids then suck up.
http://www.pbs.org/kcet/shapeoflife/episodes/ulti_explo2.html
Ossicles overlap and are fused into test
Urchins also have pedicellariae
“Urchin Barren”-destruction of kelp beds by unchecked urchins
Grazers: algae Powerful chewing apparatus called
the Aristotle's lantern- five jaws
http://www.biology.ualberta.ca/facilities/multimedia/uploads/zoology/Aristotle.swf
http://video.nationalgeographic.com/video/player/animals/invertebrates-animals/other-invertebrates/sea_urchin_breeding.html
Branching tentacles surround the mouth Respiratory trees near anus Suspension/deposit feeders They cycle up to 90% benthic biomass in ocean Defense: skin secretes toxins and they can
expel organs (autotomic evisceration) http://video.nationalgeographic.com/video/player/kids/animals-pets-kids/
invertebrates-kids/sea-cucumber-kids.html
Move quickly moving arms Arms are long, slender, and flexible Ability to autotomize: spontaneous casting
of limb No suckers on tube feet-some have mucus
to help them stick to things and capture prey
Five jaws
Most live in deep sea Feather Stars: some are free swimming Sea Lillies: most are sessile- only attached
suspension-feeding echinoderms Cirri used to attach or grab substrate Brood their young http://encarta.msn.com/media_461543142/
feather_star.html
Filter Feeders (mostly deep sea OM) Cirri used to attach
or grab substrate