Jellyfish

There are over 200 different species of jellyfish in the oceans. They cover the entire spectrum of the oceans depths from shallow bays and lagoons to the deepest, largely unexplored regions of the aquatic domain. The most recognized jellyfish is the moon jellyfish.

Jellyfish are best described as a sac within a sack. They are composed of about 95% water, 3% salt and 2% protein. They have no eyes, no brains, and no supporting skeletal system but yet are one of the oldest multi-cellular creatures know today. They do not have specialized digestive, respiratory or circulatory systems. In fact, they don’t even have blood cells. Oxygen is absorbed by simple diffusion through their outer membranes. A second membrane within the jellyfish contains a gastrodermal lining which forms a gastrovascular cavity. This cavity functions in place of a digestive system. Nutrients are absorbed and distributed throughout the body. Jellyfish either have a single mouth or multiple mouth openings positioned on oral arms that function for both intake of nutrients and expulsion of waste.

Most Jellyfish are also very dangerous to humans. They shoot out venom and there is a rare chance of survival. The pain is so excruciating that you would most likely go into shock and drown before reaching the shore. Make sure to watch out for jellyfish when swimming in any ocean.

Jellyfish can look harmless, but in reality they are deadly creatures that people need to be careful to avoid.