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What class do echinoderms belong to?
class Asteroidea
The most well-known echinoderms are members of class Asteroidea, or sea stars. They come in a large variety of shapes, colors, and sizes, with more than 1,800 species known so far.
phylum Chordata
Members of the phylum Echinodermata include sea stars (starfish), sea urchins, sea cucumbers, sand dollars, brittle stars, and feather stars. Echinoderms are the most closely related phylum to the phylum Chordata, which includes many complex organisms such as humans.
Why is phylum Echinodermata named so?
Echinodermata are so named owing to their spiny skin (from the Greek “echinos” meaning “spiny” and “dermos” meaning “skin”), and this phylum is a collection of about 7,000 described living species. Sea stars (Figure 1), sea cucumbers, sea urchins, sand dollars, and brittle stars are all examples of echinoderms.
Which of the following animal belongs to phylum Chordata?
Chordata is a familiar phylum that includes organisms like mammals, fish, birds, reptiles, and amphibians (all vertebrates); sea squirts (tunicates); and lancelets (cephalochordates). All chordates have a notochord, a dorsal nerve cord, and pharyngeal slits at some point in their development.
How did the echinoderm phylum get its name?
Projections from the skeleton, sometimes resembling spikes, which are typical of echinoderms, give the phylum its name (from Greek echinos, “spiny,” and derma, “skin”). The surface of holothurians, however, is merely warty.
How many species of echinoderms are there in the world?
An independent analysis in 2015 of RNA transcriptomes from 23 species across all classes of echinoderms gave the same tree. There are a total of about 7,000 extant species of echinoderm as well as about 13,000 extinct species. They are found in habitats ranging from shallow intertidal areas to abyssal depths.
What kind of body plan does an echinoderm have?
echinodermEchinoderms exhibit a variety of body plans. The starfishes are also called sea stars. Although they commonly have five arms, some can have many more. Basket stars have branched and coiling arms. Many brittle stars are quick and agile in comparison to most other echinoderms, especially the almost immobile sand dollar.
What makes sea stars different from other echinoderms?
The characteristics of sea stars that set them apart from other echinoderm classes include thick arms that extend from a central disk where organs penetrate into the arms. Sea stars use their tube feet not only for gripping surfaces but also for grasping prey.