The Deuterostomia I Flashcards
1
Q
Where are the Deuterostomia
A
in the Bilatera
2
Q
Deuterostomia contain the
A
- Echinoderms
- Hemichordates
- Chordates
3
Q
What do the deuterostomes have in common?
A
- deuterostome condition (mouth forms second)
- radial cleavage
4
Q
List the 5 Echinoderm Classes
A
- Asteroids (starfish)
- Ophiuroids (brittle stars)
- Echinoids (sea urchins)
- Holothurians (sea cucumbers)
- Crinoids (sea lilies and feather stars)
5
Q
Describe Echindoderms
A
- Pentaradial symmetry
- Water vascular system
- Endoskeleton
- Marine
6
Q
Describe an asteroid
A
- madreporite
- imperfect pentaradial symmetry (secondary)
- aboral side is the lump
7
Q
Describe the asteroid endoskeleton
A
- ossicles of calcium carbonate
8
Q
Describe Ophiuroids (= brittle stars)
A
- thinner, moveable arms
- flexibility between exoskeleton ossicles
- detritus feeders
- no anus (secondarily lost)
9
Q
Describe Echinoids (sea urchins)
A
- spines have living tissue over them
- pedicellaria for chopping up little larvae etc that land
- lantern
- lantern protractor muscles
- perignathic girdle
- lantern retractor muscle
- secondary bilateral symmetry, superimposed on top of the pentaradial symmetry
10
Q
Describe the transition from Asteroids to Echinoids
A
- central body larger
- fold up arms
- fuse ossicles into plates
- grow more spines
11
Q
Describe secondarily evolved pentaradial symmetry
A
- sand dollar
- sea potato or heart urchin
- burrowing helped by directed locomotion
12
Q
Describe Holothurians (= sea cucumbers)
A
- turn on side
- reduce ossicles
- remove spines
- stretch and elongate
- if attacked, ejects sticky thread-like Cuvierian tubules
- some can eject intestine as well.
13
Q
Describe Holothurian morphology
A
- stone canal
- ring canal
- internal madrepore
- oesophagus
- Polian vesicle
- dorsal mesentery
- anus
- cloaca
- cloacal muscles
- intestine
- left respiratory tree
- coelom
- stomach
- gonad
- gonadal duct
- tentacle
- pharyngeal bulb
14
Q
Describe the Crinoids (= sea lilies and feather stars
A
- turn upside down (mouth up)
- add stalk or cirri
- e.g. feather star
15
Q
Describe the Hemichordates
A
- 85 species
- Class Enteropneusts (=acorn worms)
- Class Pterobranchs
