The jellyfish is a fairly simple creature, lacking a head, a brain, a skeleton or skin. Although it can swim, it is related to stationary life forms like anemones and corals. The body of a typical jellyfish is shaped like a bell and made of transparent jelly. This allows it to float, and it can swim by contracting muscles in the walls of the bell. Out of water, however, a jellyfish will collapse into a heap of mucus. Around the edges of the bell are small nodes called rhopalia, which are the animal’s sense organs. Also lining the rim of the bell are its tentacles, which when touched will administer a sting. The jellyfish can use this to capture prey, or in self-defense. Some species have a mild venom that people will barely feel, but in others, like the Australian box jellyfish, the venom can be deadly. Underneath the bell is a funnel-like mouth, leading to the stomach pouch in the bell’s interior. All in all, the jellyfish’s body plan has successfully functioned for half a billion years. Over that time, however, jellyfish haven’t just been surviving. __________________________________
Choices:
a. Despite their simplicity, they are highly effective predators, able to consume fish and many other more complex organisms.
b. Many species of jellyfish are endangered, and we need to do more to make sure these beautiful animals will still be around in the next century.
c. Their complexity has made them an interesting object of study for biologists.