Jellyfish are floating aquatic animals with umbrella-shaped tentacles that trail behind them. Itshabitats are widespread throughout the world, from shallow waters to deep oceans. Large andvibrant jellyfish are typically seen in coastal zones worldwide. Being the oldest category ofmulti-organ animals, jellyfish have been around for at least 500 million years and possibly morethan 700 million years. In biology, jellyfish are commonly utilized in experiments. The greenfluorescent protein (GFP) that some jelly species produce can cause bioluminescence and serves asa luminescent biomarker for genes that have been integrated into different cells or species.
One of the world's mostpoisonous animals is
the Box Jellyfish, namely the Carybdeabranchi. Referred to by their body structure, boxjellyfish feature square-shaped bells and tentacles coveredwith nematocysts, which are microscopic dartsfilled with poison. Any organism that comes intocontact with its toxin will suffer severe impairment of the heart, neurological system, and skin cells. Within a few minutes of being stung, those humans and animals may go into cardiac arrest, paralysis, and even perhaps death. While the majority of box jellyfish are located in warm coastal seas, the lethal types are mostly found in the Indo-Pacific region and northern Australia. Another distinguishing aspect of box jellyfish is that they haveclusters of eyes on either side of the box, allowing them to see and swim towards their preyintensely.
Fried Egg Jellyfish, also known asEgg-Yolk Jellies, gets its common name from itssmooth translucent bell, which has an elevatedyolk-yellow bell in the center, giving theappearance of a cracked egg floating through the water. This jellyfish has no respiratory, circulatory,or excretory systems in its body. By contrast, itperforms all necessary activity in those systemsusing its vast surface area. It has numerous shortappendages that extend from the mouth-brachial openings which the jellyfish use to forage and capture prey. The top smooth spherical bell can growup to 35cm in diameter and pulses as it swims. Despite its ability to swim in water, fried egg jellyfish prefer to drift with the currents while remaining stationary.
The Lion's ManeJellyfish is the world's
largest jellyfish species. Someindividuals even rival the size of the blue whale, thebiggest mammal, with tentacles up to 120 feet long.Its colloquial name comes from its thickhair-like tentacles. Furthermore, the tentacles thatencircle the mouth and hang from the underside of its body are separated into eight clusters, each with up to 150 tentacles. The upper portion of the Lion's Mane Jellyfish bell is normally dark yellow or red, thick, and thins out towards the edges. The tentacles are armed with nematocysts that contain poison and paralyze prey when they are engulfed. Lion's manejellyfish also have bioluminescent properties, which means they can generate their own light andglow in the dark.
Jellyfish have two different body forms during their life cycles: Medusa and Polyps. Polypsreproduce asexually via budding, whereas medusae reproduce sexually by spawning eggs andsperm. The process of sperm fertilization into eggs, which develop into larval planulae, takes threedays. The larva matures into polyps, then into ephyrae, and finally into adult medusae. If there is asubstantial quantity of food, jellyfish spawn their egg or sperm on a regular basis as they reachadulthood. In the majority of species, spawning is regulated by light, with all individuals spawningaround the same time of day, usually at dawn or dusk. Jellyfish are typically either male or female,with some exceptions of hermaphrodites, which have both male and female reproductive systems.