Jellyfish predate dinosaurs. How have they survived so long? - David Gruber

Summary

Jellyfish, with over 1,000 species, are ancient ocean dwellers dating back 500 million years. These soft-bodied creatures have a simple nervous system and unique abilities like 360-degree vision and potent venom. Some can even bioluminesce, thanks to green fluorescent protein (GFP), which has revolutionized biological research. Despite climate changes, jellyfish continue to thrive and multiply, with some species capable of reverting to a polyp state to escape death.

Takeaways

• 🌊 Jellyfish are ancient sea creatures that have existed for at least 500 million years, possibly over 700 million.
• 🐙 They are not fish but belong to a diverse group of gelatinous zooplankton, with over 1,000 known species.
• 🌌 Jellyfish have a translucent bell made of mesoglea, which is over 95% water and allows them to contract and relax to move.
• 🧠 Despite lacking a brain or spinal cord, jellyfish have a neural net that forms a simple nervous system to sense their environment.
• 🍽 They do not have a typical digestive system; instead, they consume plankton and small sea creatures through a hole in their bell.
• 👀 Some jellyfish, like the box jellyfish, possess an array of eyes, including ones that allow for a 360-degree view of their surroundings.
• 🔪 The sting of a jellyfish is its most notorious feature, with some species having venom potent enough to kill a human in minutes.
• 🌟 One species of jellyfish produces green fluorescent protein (GFP), which has been crucial for scientific research and has earned Nobel Prizes.
• 🏆 The discovery and application of GFP have been recognized with Nobel Prizes, highlighting the significance of jellyfish in scientific advancements.
• 🌡️ Jellyfish are thriving in changing ocean conditions, with some species laying tens of thousands of eggs, contributing to their success.
• 💀 The 'immortal jellyfish' can revert to a polyp state to regenerate, effectively bypassing death and making it a unique species in terms of mortality.

Q & A

How long have jellyfish inhabited the ocean?

Jellyfish have inhabited the ocean for at least half a billion years, and ancient fossils suggest they may go back over 700 million years.

What is the composition of a jellyfish's bell?

A jellyfish's bell is made of a soft, delicate material called mesoglea, which is more than 95% water held together by protein fibers.

How do jellyfish propel themselves?

Jellyfish can contract and relax their bells to propel themselves through the water.

What kind of nervous system do jellyfish have?

Jellyfish have a rudimentary nervous system formed by a neural net around the inner margin of the bell's edge that can sense ocean currents and the touch of other animals.

How do jellyfish consume food and excrete waste?

Jellyfish consume plankton and other small sea creatures through a hole in the underside of their bells, and the nutrients are absorbed by an inner layer of cells, with waste excreted back through their mouths.

What is unique about the vision of box jellyfish?

Box jellyfish have 24 eyes, including four curved upward on stalks, which may provide them with a 360-degree view of their environment.

How does the jellyfish's sting work?

The jellyfish's sting is delivered through cells called nematocysts in its epidermis, which can shoot with explosive force, exerting over 550 times the pressure of Mike Tyson's strongest punch to inject venom into the victim.

What is the significance of the green fluorescent protein (GFP) found in some jellyfish?

Green fluorescent protein (GFP) is a biofluorescent compound that glows green when the jellyfish is agitated. Scientists have used GFP to track genetic modifications and biological processes, leading to Nobel Prizes in 2008 and 2014.

How are jellyfish adapting to the changing ocean conditions?

Jellyfish are thriving in warmer and more acidic oceans, possibly due to their ability to lay as many as 45,000 eggs in a single night and their unique survival strategies.

What is unique about the 'immortal jellyfish' and its survival strategy?

The 'immortal jellyfish' can revert to an immature polyp stage when sick, aging, or under stress, effectively creating new clones of itself and bypassing traditional mortality.

How many species of jellyfish are there, and are there other creatures often mistaken for them?

There are more than 1,000 species of jellyfish, and many other creatures are often mistaken for them.