Echinoderms Flashcards
Give examples of animals in the phylum Echinodermata
- Starfish
- Sea urchins
- brittle stars
- sand dollars
- sea cucumbers
- feather stars
Name some characteristics of deuterostomes
- Radial cleavage
- Coelom fuses instead of splitting
- Anus forms from/near blastopore, mouth a new formation
- Embryology usually indeterminate (regulative)
What habitats do echinoderms live in?
Marine- intertidal zone to abyssal
How many species of echinoderms are there?
Phylum has around 7000 living species
Is there parasitic echinoderms?
No
What is the five characteristics of echinoderms?
- Spiny skin
- Internal Skeleton
- Five part body
- Water vascular system
- Tube Feet
What are the five classes of echinoderms
- Asteroidea (Sea Stars)
- Ophiuroidea (Brittle stars)
- Echinoidea (Sea Urchins and Sand dollars)
- Crinoidea (Feather Stars and Sea Lillies)
- Holothuroidea (Sea Cucumbers)
Describe Asteroidea (sea stars)
- Multiple arms radiating from central disk
- Tube feet on bottom
Describe Ophiuroidea (Brittle Stars)
- Distinct central disk with snake like arms
- Tube feet lack suckers
Describe echinoidea (Sea urchins and sand dollars)
- No arms, but 5 rows of tube feet
- Have muscles that can move
- Spines
Describe crinoidea (Feather stars and sea lilies)
- Flexible arms used in suspension feeding
- Haven’t changed in 500 million years
Describe Holothuroidea (Sea cucumbers)
- Reduced endoskeleton
- Five rows of tube feet
What is the thin, outermost skin of echinoderms composed of
The thin outermost skin covers an endoskeleton made of tiny calcified plates and spines
What does a calcareous endoskeleton mean?
Made of calcium carbonate
What are the skeletal plates in echinoderms called?
- Ossicles
- Made from calcium carbonate
What are some unique characteristics of echinoderms
- Eyespots on the ends of arms are sensitive to light
- Tube feet- podia
- Ambulacral groove
- Regeneration of limbs
What is autotomy?
Spontaneous self amputation, when injured or attacked
-Usually can regenerate autotomised part
What is the function of the water vascular system?
-Varies water pressure to control movement and their tube feet
What type of symmetry did echinoderm ancestors have?
Bilateral symmetry
What symmetry do echinoderm adults have?
Radial symmetry
What is pentamerous?
Five-fold symmetry
-Echinoderms often exhibit this in portions of their body at some point in their life
