Phylum Echinodermata Flashcards
0
Q
Sea urchins & sand dollars
A
- long solid plates around internal organs
- sand $ burrow for protection
- sea urchins protected by spines
1
Q
7 characteristics
A
- 5-part radial symmetry
- internal skeleton
- water vascular system
- tube feet
- marine
- complete digestive tract
- coelomates
2
Q
Sea stars
A
- creep slowly on ocean floor
- mostly carnivorous (prey on bivalves)
- can regenerate body parts (if central disc is included)
3
Q
Brittle stars
A
- slender, flexible arms
- move rapidly to escape predators
- can shed arms when attacked
- can regenerate
- nocturnal
4
Q
Sea lillies and feather stars
A
- aka crinoids (ancient class)
- perch on reefs & capture plankton with tube feet
5
Q
Sea cucumber
A
- detritus feeders (suck organic matter)
- 5 rows of tube feet along body display radial symmetry
6
Q
Movement
A
- sand $ and sea urchins have protective spines on their fused exoskeletons
- sea stars and brittle stars have flexible arm joints
- sea cucumber has plates reduced to ossicles/spicules in body wall
7
Q
Describe how water vascular system aids movement
A
- water enters through maldreporite
- goes through stone canal
- enters ring canal
- enters radial canals
- enters tube feet
- muscles pull tube feet upwards and suction cup pressure is created
8
Q
Respiration
A
- diffusion across thin tube feet tissue (lots of surface area)
9
Q
Feeding
A
- herbivores (sea urchin) use 5-part jaw-like structure to scrape algae from rocks
- carnivores (sea star, brittle star) pry apart bivalve shell externally & absorbs partially digested food
- scavengers (sea cukes) vacuums ocean floor taking in sand & detritus
- filter-feeders (sea lillies) wave tube feet to capture floating phytoplankton
10
Q
Reproduction
A
- most are separate sexes
- external fertilization
- bilateral free-swimming larvae
11
Q
Internal circulation
A
- nutrients and wastes removed from body by water vascular system
12
Q
Excretion
A
- feces removed through anus
- ammonia/nitrogen wastes diffuse through water vascular system & tube feet
13
Q
Response to environment
A
- no head
- poorly developed nervous system
- has nerve ring around mouth & radial nerves
- scattered sensory cells to detect light, gravity, etc.
14
Q
Pedicillaria
A
Pincher like structure that keeps surface of organism free of debris
