BIO Exam 4: Echinoderms

What two Subphylum’s make up Phylum Deuterostomia?

Echinodermata and Chordata

What are the 2 critical innovations of Subphylum’s Echinodermata and Chordata?

deuterostome development and endoskeleton

What species are included in Phylum Echinodermata?

sea stars, brittle stars, sea urchins, sea cucumbers, and sea lilies

True or false: Species in Phylum Echinodermata free-living?

True

What type of symmetry do species in the Phylum Echinodermata have and why?

radial (bilateral larvae): adaptation for their sessile lifestyle allowing them to sense and react to stimuli from all directions since their sensory receptors and water vascular system are evenly distributed

True or false: Species in the Phylum Echinodermata have the ability to osmoregulate?

False

What are the skin gills of the Phylum Echinodermata called?

dermal branchiae

What are the defining characteristics of the Phylum Echinodermata?

radial symmetry (bilateral larvae), endoskeleton, dermal branchiae, pedicellariae, water-vascular system

What is another term used to describe the symmetry of the Phylum Echinodermata?

Pentaradial symmetry

What is pentaradial symmetry?

5 or more arms, with a central disc

What groove runs from mouth on the oral side of each arm?

Ambulacral groove

What does the Ambulacral groove do?

a pathway for movement and feeding

What is the term used to describe the rows of feet that border the Ambulacral groove protected by spines?

podia

The endoskeleton of the Phylum Echinodermata is composed of small calcareous plates called?

ossicles

What are spines?

specialized sharp ossicles; forms spiny surface

What is an ossicle made of?

micro-crystals of calcite arranged in a stereom (lattice) (unique to echioderms)

What do ossicles provide?

rigidity, support, and protection

What is dermal branchiae?

A thin and delicate covered epidermis that extends out through spaces between ossicles that is a large fluid-filled body coelom

What processes happen through the dermal branchiae?

respiration and excretion of nitrogenous waste through diffusion of dermal branchiae walls

What are pedicellariae?

small claw-shaped appendages; moveable jaws by muscles

What do pedicellariae do?

keep the body surface free of debris, protect the dermal branchaie

Where are the pedicellariae?

aboral surface

What type of movement does the water-vascular system provide?

Hydraulic pressure movement

What are ampulla?

podia with suckers and a muscular sac

What are the main functions of the water-vascular system?

locomotion, respiration, excretion, and food gathering

What is the water-vascular system?

A canal system with an external opening (madreporite)

What is the external opening of the vascular system called?

madreporite

What is a special feature of the reproduction of the Phylum Echiodermata?

They have autonomy: the ability to detach parts of their own body (defense mechanism)

True or false: sea stars can regenerate appendages or new sea stars if a body part is lost

True