Asteroidea is a term that is used to define a specific group of marine animals that are commonly known as starfish or sea stars. These animals are known for their unique appearance and their ability to regenerate lost limbs. In this article, we will explore the definition and meaning of Asteroidea, as well as its origin, associations, and synonyms.
Definitions
Asteroidea is a class of echinoderms that includes over 1,500 species of starfish. These animals are characterized by their five-point radial symmetry and their ability to regenerate lost limbs. They are found in all of the world’s oceans, from the Arctic to the Antarctic, and can range in size from a few millimeters to over a meter in diameter.
Origin
The Asteroidea class of echinoderms is believed to have originated during the Ordovician period, approximately 480 million years ago. Fossil evidence suggests that early starfish were much simpler in form than their modern counterparts, and had only a few arms or no arms at all.
Meaning in different dictionaries
In the Merriam-Webster dictionary, Asteroidea is defined as “a class of echinoderms comprising the starfishes.” The Oxford English Dictionary defines it as “a class of marine animals with five-point radial symmetry, comprising the starfishes.”
Associations
Asteroidea is often associated with marine ecosystems and the ocean environment. These animals are important predators and scavengers in many marine food webs, and their presence can indicate the health of a particular ecosystem. They are also popular among aquarium enthusiasts, and are often kept as pets in home aquariums.
Synonyms
Some synonyms for Asteroidea include sea stars, starfish, and Asterozoa. These terms are often used interchangeably to describe the same group of animals.
Antonyms
There are no direct antonyms for Asteroidea, as it is a specific term that refers to a particular group of animals.
The same root words
Asteroidea is derived from the Greek words “aster,” meaning star, and “eidos,” meaning form or shape. Other words that share the same root include asteroid, astrocyte, and astrophysics.
Example Sentences
- The Asteroidea class of echinoderms includes over 1,500 species of starfish.
- The Asteroidea are important predators and scavengers in marine ecosystems.
- Many people keep Asteroidea as pets in their home aquariums.
- The word Asteroidea comes from the Greek words “aster” and “eidos,” meaning star shape.