What is the difference between a jellyfish and starfish?

Jellyfish and starfish are both fascinating creatures, but they are very different in terms of their anatomy, biology, and classification. Here's a breakdown of their key differences:

Phylum:

* Jellyfish: Belong to the phylum Cnidaria.

* Starfish: Belong to the phylum Echinodermata.

Body Structure:

* Jellyfish: Have a bell-shaped body with tentacles. They lack a brain, heart, or bones. Their bodies are mostly made of water.

* Starfish: Have a central disc and five or more arms (though some have more). They have a hard, spiny exoskeleton and possess a central nervous system, a simple circulatory system, and a stomach that can be everted (turned inside out).

Movement:

* Jellyfish: Move by pulsing their bell, propelling themselves through the water.

* Starfish: Move using tube feet, which are small, hydraulically operated appendages found on their undersides.

Feeding:

* Jellyfish: Carnivorous, feeding primarily on plankton, small fish, and other invertebrates. They use stinging cells (nematocysts) to paralyze their prey.

* Starfish: Primarily carnivorous, feeding on clams, mussels, and other invertebrates. They use their tube feet to pry open their prey, and then evert their stomach to digest the meal externally.

Reproduction:

* Jellyfish: Reproduce sexually, with some species also exhibiting asexual reproduction. They release sperm and eggs into the water, where fertilization occurs.

* Starfish: Can reproduce both sexually and asexually. They release sperm and eggs into the water for external fertilization, but some species can also reproduce asexually by breaking off an arm.

Habitat:

* Jellyfish: Found in all the world's oceans, from the surface to the deep sea.

* Starfish: Also found in all the world's oceans, but predominantly in shallow coastal waters.

Other Notable Differences:

* Jellyfish: Are considered zooplankton (drifting animals).

* Starfish: Are considered benthic animals (living on the seafloor).

In summary, while both jellyfish and starfish are marine creatures, they are fundamentally different in their physical structures, lifestyles, and biological processes.