Ophiuroidea

Definition

Ophiuroidea, commonly known as brittle stars and basket stars, is a class of echinoderms characterized by their slender, flexible arms and a distinct central disc. They are primarily found on the ocean floor, often in shallow waters, and play important roles in marine ecosystems as scavengers and prey for various marine animals.

5 Must Know Facts For Your Next Test

1. Brittle stars have a unique anatomy with a central disc and long arms that are distinctly different from the thick arms of sea stars.
2. They use their tube feet for feeding but do not rely on them for locomotion like other echinoderms; instead, they move by bending their arms.
3. Ophiuroidea can be found in a variety of marine environments, from tidal pools to deep-sea habitats.
4. Many brittle stars are nocturnal and tend to hide under rocks or within coral reefs during the day to avoid predators.
5. Their ability to regenerate lost limbs is a significant survival adaptation, allowing them to escape from predators and continue thriving in their environments.

Review Questions

• Compare the anatomical features of Ophiuroidea with those of other echinoderms like sea stars. How do these features affect their behavior?
  • Ophiuroidea have a distinct anatomy characterized by a central disc and long, slender arms, which sets them apart from sea stars that have thicker arms radiating from a central body. This unique structure allows brittle stars to be more agile and flexible in their movements, enabling them to navigate through complex substrates. The differences in anatomy also influence their behavior; while brittle stars use their arms to crawl and evade predators, sea stars rely more on their tube feet for movement.
• Discuss the ecological roles of Ophiuroidea in marine environments. How do they contribute to ecosystem balance?
  • Ophiuroidea play vital ecological roles as both scavengers and prey within marine ecosystems. By feeding on detritus and organic matter, they help recycle nutrients back into the environment, promoting healthy sediment ecosystems. Additionally, brittle stars serve as an important food source for various marine animals, including fish and larger invertebrates. Their presence helps maintain balance within food webs, highlighting the interconnectedness of marine life.
• Evaluate the impact of environmental changes on Ophiuroidea populations and their adaptive strategies for survival.
  • Environmental changes such as ocean acidification, habitat destruction, and rising temperatures can significantly affect Ophiuroidea populations. These stressors may lead to declines in food availability or suitable habitats for these organisms. However, their adaptability is showcased through their regeneration capabilities and flexible behavior in seeking shelter. Understanding how these echinoderms respond to environmental pressures is crucial for conservation efforts aimed at preserving marine biodiversity.

Related terms

Echinodermata: The phylum that includes marine animals like sea stars, sea urchins, and brittle stars, characterized by their radial symmetry and a water vascular system.

Arms: The long, flexible appendages of brittle stars that allow for locomotion and feeding by using tube feet located on their underside.

Regeneration: The biological process by which brittle stars can regrow lost arms, allowing them to recover from predation or injury.