What type of symmetry do irregular echinoids show?
Bilateral symmetry
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What are tube feet?
The soft tissue which extend out through the test through pore pairs
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What is the water vascular system?
The hydraulic system that allows the animal to extend its tube feet bu forcing water into its tissues. The amount of water is controlled by the madreporite
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What is a tubercle for?
Spine attachment
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What is the genital plate used for?
To release sperm and eggs into the water column
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What is the madreporite used for?
Taking in water for the water vascular system
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What are the interlocking plates made out of?
Calcite
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What is the ambulacral area?
Narrow area consisting of two rows of plates, each plate has pore pairs
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What is the interambulacral plate?
Two rows of plates which may have tubercles
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Where is the mouth positioned?
On the bottom
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Where is the anus positioned?
On the top
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What is the apical system?
10 plates arranged in two rings around the central anus, there are 5 genital plates; the largest is the madreporite which is perforated by many tiny pores allowing water to enter. The anus is surrounded by a membrane called the periproct
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What membrane surrounds the mouth?
The peristome
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What is the perignathic girdle?
Where the test are turned inwards to produce a lip which allows the feeding apparatus to be attached and supported
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What is the Aristotle's lantern?
five jaws with a single sharp tooth supported inside the mouth, these teeth can scrape algae or food from the substrate and pass it inside the animal towards the gut, the mouth is on the underside to aid easy feeding
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What are the three main functions of the tube feet?
Attachment, movement and an exchange surface for respiration.
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What two things do the tubercles consist of?
The boss and the mamelon
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How does the muscle attach to the spine?
Muscle attaches the spine to the boss and as a muscle, it can contract and cause the spine to move in a coordinated manner-rotation for moving. Spines are also used for defence
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What is the regular echinoid mode of life?
Live on rocky shores, a high energy environment. They graze on algae on the substrate or by scavenging other food particles
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What is a defining characteristic of an irregular echinoid?
Having an anus outside the apical system
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What shape are irregular echinoids?
Heart-shaped
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What does the mouth lack?
Jaws and the perignathic girdle, instead they are filter feeders
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What is the labrum?
A large lip protruding over part of the mouth to prevent sediment moving into the mouth
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What is the plastron?
Area covered with tubercles, for attachment of small spines. Used to dig burrows
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What is the anterior groove?
Marks heart shape of animal, lined with cilia to direct currents to the mouth
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What is the petaloid ambulacra?
Narrow area consisting of two rows of plates. Each plate has pore pairs, forms a petal-shaped structure
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What is a fasciole?
Direct water to the mouth and one to direct waste away from the echinoid
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What is the sub-anal fasciole?
Area which has beating cilia to take waste particles and direct them into the sanitary tube
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What is the irregular echinoid mode of life?
Usually live in soft sediment and in a low-energy environment (infaunal). they are filter feeder and are able to dig burrows, they resire by extending their tube feet from the petaloid ambulacra.
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What happened to the petaloid ambulacra when the irregular echinoid evovled?
They became longer and more efficient for gas exchange
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Other cards in this set
Card 2
Front
Class
Back
Echinoidea
Card 3
Front
What type of symmetry do regular echinoids show?
Back
Card 4
Front
What type of symmetry do irregular echinoids show?
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