Echinodermata Olivia Johnson, Andrei Anashkin, Heather Schlesier

Echinoderms are slow-moving animals that only live in salt water Echinoderms are slow-moving animals that only live in salt water A unique feature is the water vascular system A unique feature is the water vascular system The phylum Echinodermata contains 6 major classes: Asteroidea (sea stars), Ophiuroidea (brittle stars), Echinoidea (sea urchins and sand dollars), Crinoidea (sea lilies and feather stars), Holothuroidea (sea cucumbers), and Concentricycloidea (sea daises) The phylum Echinodermata contains 6 major classes: Asteroidea (sea stars), Ophiuroidea (brittle stars), Echinoidea (sea urchins and sand dollars), Crinoidea (sea lilies and feather stars), Holothuroidea (sea cucumbers), and Concentricycloidea (sea daises) Phylum

Sample Animals A Sea Star A Brittle Star A Feather Star ophiuroidea.jpg star-pattern_6081.jpg

A Sea Urchin A Sea Cucumber A Sea Daisy

Body Cavity -are coelomates (posses a true coelom) -coelom (body cavity): a fluid-filled space that separates the digestive tract from the outer body wall -coelom is lined with mesoderm

Body Symmetry Adults have radial symmetry but it is a secondary adaptation (many equal parts radiate outward like the spokes of a wheel) Adults have radial symmetry but it is a secondary adaptation (many equal parts radiate outward like the spokes of a wheel) Echinoderm larvae have bilateral symmetry (can be divided into two equal halves) Echinoderm larvae have bilateral symmetry (can be divided into two equal halves)

Echinoderms have a decentralized nervous system. Echinoderms have a decentralized nervous system. There is nervous tissue throughout the echinoderm connected by central nerve ring around its gut, but they have no real brain. There is nervous tissue throughout the echinoderm connected by central nerve ring around its gut, but they have no real brain. Some echinoderms instead have ganglia, which are large clusters of nerve cells. Some echinoderms instead have ganglia, which are large clusters of nerve cells. Nervous System

Water Vascular System Unique to echinoderms it is a network of hydraulic canals branching into extensions called tub feet that function in locomotion, feeding, and gas exchange Unique to echinoderms it is a network of hydraulic canals branching into extensions called tub feet that function in locomotion, feeding, and gas exchange

Circulatory System

Digestive System

Excretory System Excretion can be preformed through diffusion Excretion can be preformed through diffusion Contains an anus on the top of the central disk Contains an anus on the top of the central disk

Made possible by the water vascular system and tube feet Made possible by the water vascular system and tube feet Sea Stars: undersurfaces of the arms have tube feet, adheres firmly to rocks or creeps along slowly as the tube feet extend, grip, contract, release, extend and grip again. Sea Stars: undersurfaces of the arms have tube feet, adheres firmly to rocks or creeps along slowly as the tube feet extend, grip, contract, release, extend and grip again. –Made possible by a complex set of hydraulic and muscular actions creating or releasing suction. Brittle Stars: serpentine lashing of their arms Brittle Stars: serpentine lashing of their arms –Tube feet lack suckers so cannot grip Locomotion/ Musculature

Sea Urchins and Sand Dollars: don’t have arms, but do have 5 rows of tube feet that function in slow movement Sea Urchins and Sand Dollars: don’t have arms, but do have 5 rows of tube feet that function in slow movement –Also have muscles that pivot their long spines that aids in movement Sea Lilies and Feather Stars: Sea lilies live attached to the substrate by a stalk; feather stars crawl about by using their long flexible arms Sea Lilies and Feather Stars: Sea lilies live attached to the substrate by a stalk; feather stars crawl about by using their long flexible arms Sea Cucumbers: have 5 rows of tube feet, some of the tube feet around the mouth are developed as feeding tentacles Sea Cucumbers: have 5 rows of tube feet, some of the tube feet around the mouth are developed as feeding tentacles Sea Daisies: they have armless bodies, not much is known about them Sea Daisies: they have armless bodies, not much is known about them

Skeletal Type A thin skin covers an endoskeleton of hard calcareous plates A thin skin covers an endoskeleton of hard calcareous plates Most echinoderms are prickly from skeletal bumps and spines Most echinoderms are prickly from skeletal bumps and spines

Regeneration allows some echinoderms to grow back lost arms or even full bodies Regeneration allows some echinoderms to grow back lost arms or even full bodies They have light and touch detecting cells but no sense organs They have light and touch detecting cells but no sense organs –Starfish are an exception, they have eyespots on the tip of each ray for light detection They do not have heads or a brain, instead they have a simple nervous system with a nerve net/ ring They do not have heads or a brain, instead they have a simple nervous system with a nerve net/ ring Sensory Structures/Features

Sexual or asexual (regeneration) Sexual or asexual (regeneration) Sexual reproduction usually involves separate male and female individuals that release their gametes into the water Sexual reproduction usually involves separate male and female individuals that release their gametes into the water Sea stars and some other echinoderms have the ability to regenerate Sea stars and some other echinoderms have the ability to regenerate Sea stars can regrow lost arms, and one specific genus can regrow an entire body from a single arm Sea stars can regrow lost arms, and one specific genus can regrow an entire body from a single arm Reproduction

Gas Exchange Do not have a circulatory system Do not have a circulatory system Exchange gas through diffusion Exchange gas through diffusion Diffusion is possible through the water vascular system Diffusion is possible through the water vascular system Structures: tube feet Structures: tube feet

Other Unique Stuff When feeding sea stars turn their stomachs inside out and then secretes juices to help it digest its prey When feeding sea stars turn their stomachs inside out and then secretes juices to help it digest its prey Current sea lilies are very similar to fossils of those that are 500 million years old: their evolution has been very conservative Current sea lilies are very similar to fossils of those that are 500 million years old: their evolution has been very conservative

Which of the following do echnodermata contain? Circulatory system Circulatory system Exoskeleton Exoskeleton Endoskeleton Endoskeleton Nervous system Nervous system

What kind of symmetry do grown echinodermata have? Bilateral Bilateral Symmetrical Symmetrical Secondary radial Secondary radial