Echinoids

Question 1

What is their phylum and types and class

Answer 1

Echinodermata
Regular and irregular
Echinoidea

Question 2

What is a regular echinoids symmetry

What is a irregular echinoids symmetry

Answer 2

Five-fold symmetry

Bilateral

Question 3

What is their soft tissue body part called

Answer 3

Tube feet

Question 4

What is the skeleton called and what shape is it

Answer 4

Test

Hemisphere

Question 5

What does it consist many of and what are they made out of

Answer 5

Many interlocking plates

Calcite

Question 6

What are the two types of plates called

Answer 6

Ambulacra

Interambulacra

Question 7

How many plates are in total and how many of each

Answer 7

10

5

Question 8

Which plate is narrower

Answer 8

Ambulacra

Question 9

How many rows of plates do the ambulacra consist of and what are they perforated by

Answer 9

2

Pore pairs

Question 10

In real life what would pore pairs have

Answer 10

Tube feet

Question 11

What do interambulacra plates have on their surface

Answer 11

Tubercles

Question 12

In real life what would tubercles have attached on them

Answer 12

Spines

Question 13

What view is where the anus if facing up

Answer 13

Aboral

Question 14

What view is where the mouth is facing up

Answer 14

Oral

Question 15

What is the madreporite

Answer 15

Genital plate for taking in water for the water vascular system

Question 16

What were the tube feet used for

Answer 16

Respiration
Movement
Attachment

Question 17

Where is the apical system

Answer 17

In the centre of the upper or aboral surface

Question 18

The apical system consists of what

Answer 18

Ten plates arranged in two rings around a centre anus

Question 19

How many genital plates are there and what is the largest

Answer 19

5

Madreporite

Question 20

How does the madreporite work

Answer 20

It is perforated by many tiny pores allowing water to enter the animals water vascular system

Question 21

In-between the large plates are what

Answer 21

Smaler genital plates

Question 22

What is the anus surrounded by and what does it release

Answer 22

A membrane called the periproct

Waste, legs and sperm

Question 23

What is the mouth surrounded by

Answer 23

A membrane called the peristome

Question 24

How are the edges of the test shaped and what does this produce

Answer 24

They are turned inwards producing a lip

Question 25

What is this lip called

Answer 25

The perignathic girdle

Question 26

What is the structure of the feeding apparatus and what is it called

Answer 26

There are five jaws, each with a sharp tooth supported inside the mouth called Aristotle's lantern

Question 27

What do the tubercles consist of

Answer 27

``` The boss (a wide base) the mamelon (a nipple like structure in the centre of the boss) ```

Question 28

How are the spines attached

Answer 28

Muscles attach the spine to the boss and the muscles contract to move the spines in a chosen direction

Question 29

What is the mode of life for regular echinoids

Answer 29

Live on rocky shores High-energy environment Feed on algae by scrapping it off rocks

Question 30

How are irregular echinoids characterised

Answer 30

By having the anus outside of the apical system | The anus has moved towards the edge of the test

Question 31

Named examples of irregular echinoids

Answer 31

Micraster | Sad dollar

Question 32

What does the mouth lack (Irregular)

Answer 32

Jaws and the perignathic girdle

Question 33

How does it feed (Irregular)

Answer 33

It takes in particles of water and filters these

Question 34

What is the labrum, where is it and what does it do

Answer 34

Large lip On the lower side of the mouth Used to direct the currents and prevent unwanted sediments getting into the mouth

Question 35

What is behind the labrum and what does it form

Answer 35

A modified set of interambulacra plates | Plastron

Question 36

What does the plastron have and do

Answer 36

Tubercles for attachement of spines | The spines are used to help dig a burrow or to move within it

Question 37

What is the ambulacra called on irregular echinoids

Answer 37

Petaloid ambulacra

Question 38

What do the petaloid ambulacra at the anterior end of the animal form

Answer 38

They are bigger | Form the anterior groove

Question 39

What is the anterior groove lined with and what do they do and what is it called

Answer 39

Lined with cilia Beat to create a current to pass food particles to the mouth Called the fasciole

Question 40

What is the modified area close to the anus called (Irregular)

Answer 40

Sub-anal fasciole

Question 41

What does the sub-anal fasciole do

Answer 41

Many beating cilia to take waste particles and direct them into the sanitary tube

Question 42

How are the tube feet on the two posterior ambulacra modified

Answer 42

To keep the burrow clean and maintain the sanitary tube

Question 43

What is their mode of life (Irregular)

Answer 43

Live in soft sediment Low-energy environment (infaunal) Filter feeder