BIO 131- Deterostomes: Echinoderms

Which three phyla are classified as deuterostomes?

Chordata, Echinodermata, Hemichordata

Are vertebrates considered their own phylum?

No

Vertebrates belong to which phylum?

Chordata

In deuterostomes, what does the blastopore develop into?

The anus

What type of cleavage pattern do deuterostomes exhibit?

Radial Cleavage

What does “indeterminate cleavage” mean?

Cells retain the ability to become a complete organism

What type of symmetry do echinoderm larvae have?

Bilateral Symmetry

What type of symmetry do adult echinoderms have?

Pentaradial Symmetry

What is the name of the system echinoderms use for movement and feeding?

Water Vascular System

What structure allows water to enter the water vascular system?

Madreporite

What type of coelom formation occurs in deuterostomes?

Enterocoely

What are the two main clades of deuterostomes?

Chordata and Ambulacraria

Which two phyla belong to the clade Ambulacraria?

Echinodermata and Hemichordata

Name one synapomorphy of deuterostomes.

radial cleavage, indeterminate development

What is the function of tube feet in echinoderms?

Locomotion, feeding, and gas exchange

What composes the echinoderm endoskeleton?

Calcium carbonate ossicles (plates)

Describe the basic organization of the echinoderm nervous system.

Nerve ring with radial nerves extending outward

Do echinoderms have a centralized brain?

No, not at all

What type of fertilization is most common in echinoderms?

External Fertilization (dioecious)

What major evolutionary transition occurs in echinoderm symmetry?

Bilateral larvae → pentaradial adults

“Radial cleavage, blastopore becomes anus, enterocoely” → what major group?

Deuterostomes

“Outpocketing of the gut forms the coelom” → what process?

Enterocoely

“Spiny-skinned organism with calcium carbonate plates” → what phylum?

Echinodermata

“Water enters through madreporite → where does it go next?”

Stone Canal

“Organism with no brain but a nerve ring and radial nerves” → what group?

Echinoderms (phylum Echinodermata)

“Early embryo cells can each become a full organism” → what property?

Indeterminate cleavage

“Five-part radial symmetry in adults, bilateral larvae” → what group?

Echinoderms

“Deuterostome clade that includes vertebrates” → ?

Chordata

“Deuterostome clade that includes echinoderms and hemichordates” → ?

Ambulacraria

“Fossil organism showing early chordate-like features” → name it

Yunnanozoon

“Organism: elongated, soft-bodied, reduced skeleton” → which echinoderm class?

Holothuroidea

“Organism: brittle arms, moves rapidly, distinct central disc” → which class?

Ophiuroidea

“Organism: spherical body, spines, Aristotle’s lantern” → which class?

Echinoidea

“Organism: many feathery arms, often attached/sessile” → which class?

Crinoidea

“Organism: thick arms, gradual transition from central disc” → which class?

Asteroidea