How is a starfish body more complicated than sponge?

While both starfish (sea stars) and sponges are invertebrates, the starfish's body is significantly more complex than a sponge's in several ways:

1. Organ Systems:

* Starfish: Have well-defined organ systems like a digestive system, nervous system, circulatory system, and reproductive system.

* Sponges: Lack distinct organs or organ systems. They have specialized cells that perform specific functions, but these cells are not organized into organs.

2. Symmetry:

* Starfish: Exhibit radial symmetry, meaning they can be divided into equal parts around a central axis.

* Sponges: Have asymmetrical body structures, lacking any consistent shape or symmetry.

3. Movement:

* Starfish: Can move independently using their tube feet, which are hydraulically powered.

* Sponges: Are sessile, meaning they remain attached to one location and cannot move freely.

4. Feeding:

* Starfish: Are active predators, using their tube feet to pry open prey like shellfish, and their stomachs to digest food externally.

* Sponges: Filter feeders that draw water through their pores and extract food particles.

5. Nervous System:

* Starfish: Have a decentralized nervous system with a nerve ring around the mouth and radial nerves extending into each arm. They can sense light, chemicals, and touch.

* Sponges: Lack a central nervous system or specialized sense organs. Their responses are primarily driven by individual cell reactions.

6. Reproduction:

* Starfish: Can reproduce sexually through the release of eggs and sperm. They also have the ability to regenerate lost arms.

* Sponges: Reproduce both sexually and asexually through budding or fragmentation.

In essence, starfish exhibit a more complex level of organization and specialization than sponges, with distinct organs and organ systems that allow them to perform a wider range of functions and interact with their environment in more sophisticated ways.