15_PHYLUM ECHINODERMATA
GENERAL CHARACTERISTICS
- “spiny-skinned”
- highly-organized marine invertebrates
- coelomate
- thrives in marine environment
- primitive senses
- water vascular system
DISTINCT CHARACTERISTICS
- Calcareous skeleton (crystalline calcite)
- Non-parasitic
- Tube feet (podia)
- primitive bilateral symmetry masked by a strong 5-fold radial symmetry
ARTHOPODA SIMILARITIES ECHINODERMATA
-exoskeleton -bilaterally -skeleton enclosed in
symmetrical soft tissues
-respiratory
system -highly varied -osmotic regulation
-chitinous -calcareous skeleton
skeleton
ECHINODERMATA SIMILARITIES CHORDATA
-absence of -bilaterally -notochord
notochord symmetrical
-phosphatic
-calcite skeleton -larval stage skeleton
-tube feet -central -respiratory
nervous system
-water vascular
system
system
-body fluid
proteins
, MODE OF LIFE
GENERAL
- known only to live in marine environments, though some can be found in
brackish water
- vary from filter feeders to active predators
- filter feeders - mud passes through the alimentary tract
- no true planktonic echinoderms
CRINOIDS
- live in strong currents, such as zone of breaking waves
- shallow waters to abyssal depths
- filter feeders
- two types: stem-bearing / stalked and free-swimming
ASTEROIDS AND OPHIUROIDS
- sea stars and brittle stars
- littoral zones and deep waters
- muddy bottom
- survival mechanism: fast / slow movement
ECHINOIDS
- mobile algae grazers
- most burrow, but some use their spines or tube feet to anchor themselves
- found from intertidal zone to deep marine
HOLOTHUROIDS
- muddy bottom
- survival mechanisms
o slow creeping
▪ swimming
▪ burrowing
- tube feet
SEXUAL REPRODUCTION
- simple reproductive organs
- the eggs are released and fertilized externally
- larva is bilaterally symmetrical, is free-swimming, and lacks calcareous skeleton
GENERAL CHARACTERISTICS
- “spiny-skinned”
- highly-organized marine invertebrates
- coelomate
- thrives in marine environment
- primitive senses
- water vascular system
DISTINCT CHARACTERISTICS
- Calcareous skeleton (crystalline calcite)
- Non-parasitic
- Tube feet (podia)
- primitive bilateral symmetry masked by a strong 5-fold radial symmetry
ARTHOPODA SIMILARITIES ECHINODERMATA
-exoskeleton -bilaterally -skeleton enclosed in
symmetrical soft tissues
-respiratory
system -highly varied -osmotic regulation
-chitinous -calcareous skeleton
skeleton
ECHINODERMATA SIMILARITIES CHORDATA
-absence of -bilaterally -notochord
notochord symmetrical
-phosphatic
-calcite skeleton -larval stage skeleton
-tube feet -central -respiratory
nervous system
-water vascular
system
system
-body fluid
proteins
, MODE OF LIFE
GENERAL
- known only to live in marine environments, though some can be found in
brackish water
- vary from filter feeders to active predators
- filter feeders - mud passes through the alimentary tract
- no true planktonic echinoderms
CRINOIDS
- live in strong currents, such as zone of breaking waves
- shallow waters to abyssal depths
- filter feeders
- two types: stem-bearing / stalked and free-swimming
ASTEROIDS AND OPHIUROIDS
- sea stars and brittle stars
- littoral zones and deep waters
- muddy bottom
- survival mechanism: fast / slow movement
ECHINOIDS
- mobile algae grazers
- most burrow, but some use their spines or tube feet to anchor themselves
- found from intertidal zone to deep marine
HOLOTHUROIDS
- muddy bottom
- survival mechanisms
o slow creeping
▪ swimming
▪ burrowing
- tube feet
SEXUAL REPRODUCTION
- simple reproductive organs
- the eggs are released and fertilized externally
- larva is bilaterally symmetrical, is free-swimming, and lacks calcareous skeleton
