In echinoderms bilateral symmetry found in larval stage but in adult echinoderms radial symmetry is found.

Understanding Echinodermata Symmetry
Echinodermata, a phylum that includes starfish, sea urchins, and sea cucumbers, is notable for its unique body structure and symmetry.
Radial Symmetry in Echinodermata
- Echinoderms exhibit radial symmetry, which means their body parts are arranged around a central axis.
- This symmetry allows them to interact with their environment from all directions, which is advantageous for their lifestyle in marine ecosystems.
Characteristics of Radial Symmetry
- Multiple Planes of Symmetry: Echinoderms can be divided into similar halves across multiple planes. For instance, a starfish can be split into equal parts through any line that passes through its central mouth.
- Adaptation for Sedentary Lifestyle: Many echinoderms are either sessile or slow-moving, making radial symmetry ideal for their feeding and defensive strategies.
Comparison with Other Symmetries
- Bilateral Symmetry: This is found in organisms like humans and most animals, where the body can be divided into two identical halves. Echinoderms do not possess this feature as adults.
- Porous Body and Soft Skin: While echinoderms do have a porous body and a soft skin, these features are not related to their symmetry. The porous body aids in respiration and the soft skin is covered by a calcareous endoskeleton.
Conclusion
In summary, the defining characteristic of Echinodermata is their radial symmetry. This feature plays a crucial role in their ecological interactions and evolutionary adaptations, distinguishing them from other phyla like those exhibiting bilateral symmetry.