Language
Country/Area
No result found
Ghosts Underwater: How Do Jellyfish Survive in the Ocean?
Jellyfish, also known as sea jellyfish, are the medusa stage of certain gelatinous animals that belong to the ancient phylum Cnidaria. This unique creature can swim freely in the ocean, and some species even stay fixed to the seabed. Jellyfish are currently known to have a long history of more than 500 million years, making them one of the oldest groups of multicellular animals on Earth. While admiring the graceful movement of jellyfish, scientists have also begun to explore how these ocean ghosts survive in the ever-changing marine ecology.
The main body of a jellyfish is a round, fleshy structure called the "umbrella", and below it are hanging tentacles used to capture prey and defend themselves.
The survival mechanism of jellyfish is quite strange. Their bodies are about 95% water and rely on their gelatinous "mesoglenoid" structure to maintain shape and allow movement. This gelatinous umbrella provides propulsion for the jellyfish in the water through pulsating contraction, allowing it to move freely in the ocean. The tentacles are equipped with stinging cells, which help the jellyfish capture prey or fight off predators.
The Complex Life Cycle of JellyfishJellyfish have an extremely complex life cycle. The jellyfish stage is usually their sexual reproduction phase and will produce a planned stage called larvae. These larvae then disperse and enter a static polyp stage, which reproduces asexually at some point in its life, eventually reaching sexual maturity. Over time, many jellyfish experience changes in their environment and survive because of their adaptability.
Although jellyfish grow quickly, often maturing within a few months, the polyp stage can sometimes live much longer, allowing jellyfish to respond flexibly to the ever-changing marine ecosystem.
Relationship between jellyfish and humans
In some cultures, jellyfish are eaten, particularly in some Asian countries where certain jellyfish are considered a delicacy. The jellyfish are pressed and salted to remove excess water. Australian researchers have even described jellyfish as "a perfect food" because they are sustainable, high in protein but relatively low in energy.
While jellyfish are considered a delicacy in some cultures, their stinging cells are rightly feared, with thousands of swimmers worldwide suffering jellyfish stings each year, with effects ranging from mild discomfort to to serious injury or even death.
Ecological impact of jellyfish
When conditions are right, jellyfish can form huge swarms that can sometimes harm fisheries by filling up fishing nets and occasionally clogging cooling systems at power and desalination plants that draw water from the sea. Such ecological dynamics undoubtedly have an impact on human activities and even marine ecology, making it particularly important to study the survival and reproduction patterns of jellyfish.
Visual system of jellyfish
The visual system of jellyfish is quite special. Although it is traditionally believed that they lack a central nervous system, jellyfish actually have a "neural network" structure. Each jellyfish species has a different visual system, ranging from simple light-sensing cells to more complex image-forming eyes, with the tetrapod jellyfish showing even more advanced vision.
ConclusionThe visual system of jellyfish is key to studying how evolution has changed the behavior of underwater creatures, as their visual abilities allow them to effectively navigate their environment and avoid predators.
Overall, jellyfish's survival strategies are full of adaptability and resilience, and their life cycles, reproduction methods, and interactions with the ecosystem all demonstrate the wonders of nature. As we learn more about jellyfish ecology, we can't help but wonder, as the environment changes, what role will jellyfish play in the future marine ecology?
