Echinoderms Flashcards
(11 cards)
What two groups are sister taxa according to morphological evidence?
Echinoderms and Hemichordates.
What is the relationship between Echinoderms, Hemichordates, and Chordates?
Echinoderms and Hemichordates form a sister group, and together they are a sister group to Chordates.
What does “Echinoderm” mean in Greek?
“Spiny skin” (echinos = spiny, derma = skin).
How many species are in the phylum Echinodermata?
Approximately 7,500 species.
Are echinoderms marine, freshwater, or terrestrial?
Exclusively marine.
What animals are included in Echinodermata?
Seastars, brittle stars, urchins, sand dollars, sea cucumbers, and sea lilies.
What is the size range of echinoderms?
From less than 1 cm to over 3 meters in length.
Where are echinoderms found in the ocean?
At all depths, from shallow shores to deep sea
What unique system do echinoderms have for locomotion?
A water vascular system that powers their tube feet.
What are crinoid feather stars known for?
Their beautiful appearance and ability to actively swim.
Why might crinoid feather stars be surprising in terms of evolutionary relationships?
Despite their appearance, they are relatively closely related to chordates.
