Marine Biologist Answers Fish Questions From Twitter | Tech Support | WIRED

Summary

This video delves into fascinating marine biology topics, exploring the wonders of ocean life. It covers the bioluminescence in marine creatures used for defense, the immortality of jellyfish and their ability to revert to juvenile stages, and the long lifespans of animals like Greenland sharks and whales. Additionally, it explains the curious evolution of crabs and their relatives, and addresses questions about fish sleep and how they manage breathing while resting. Engaging and informative, the video provides insight into the unique adaptations and behaviors of marine life.

Takeaways

• 😀 Some animals, like the glow-worm, release bioluminescence to disorient predators, using openings in their exoskeletons.
• 😀 The immortal jellyfish can revert to its juvenile form when injured or starving, allowing it to potentially live forever.
• 😀 Greenland sharks can live up to 600 years, making them one of the longest-living animals on Earth.
• 😀 Many whales have lifespans that extend for hundreds of years, with some carrying harpoons from old whaling ships embedded in them.
• 😀 Lobsters, while not truly immortal, can live for a long time, but may eventually die when unable to escape their molted shells.
• 😀 Evolution has led to multiple non-crab species evolving into crab-like forms, a process known as carcinization.
• 😀 Hermit crabs, which evolved from shrimp or skinny lobsters, exhibit features similar to true crabs after millions of years of evolution.
• 😀 Fish sleep without eyelids, and while part of their brain shuts off, they continue to breathe and can be touched while resting.
• 😀 Whales, like sperm whales, sleep with part of their brain active to ensure they can continue to breathe while resting.
• 😀 Sperm whales sleep vertically in pods, creating the illusion of a 'forest' of whales floating in the ocean.

Q & A

What happens when a kinked worm is startled or disturbed?

When a kinked worm is startled or disturbed, it releases bioluminescence to disorient predators. This bioluminescence is emitted through openings in their exoskeletons.

Why are jellyfish considered immortal?

Some species of jellyfish, like the 'immortal jellyfish,' can revert back to their juvenile stage if they are injured or starving. This ability allows them to essentially bypass death, as they can later regenerate into a genetically identical clone.

How long can Greenland sharks live?

Greenland sharks can live for up to 600 years, making them one of the longest-living animals on the planet.

Why do some whales have old harpoons embedded in them?

Some whales still have old harpoons embedded in them because they can live for hundreds of years. This indicates that they have survived past whaling attempts from historical harpoon ships.

How do lobsters grow and why might they live for a long time?

Lobsters grow by molting, where they shed their old exoskeleton to allow a new one to form. While molting, they are vulnerable, but if they manage to survive the process, they can live for an indefinite period. However, older lobsters may eventually die from failing to molt successfully.

Why does evolution keep producing crabs?

Although it's unclear why evolution continues to produce crabs, many animals that are not crabs evolve into forms that resemble crabs. For example, hermit crabs evolved from shrimp-like ancestors by rolling their tails up, enlarging their claws, and developing other features that resemble true crabs.

Do fish sleep even though they don’t have eyelids?

Yes, fish do sleep. Even though they don’t have eyelids, they enter a sleep state where part of their brain shuts off, and they still breathe. While sleeping, their response to stimuli is reduced, allowing them to remain undisturbed.

How do whales sleep without drowning?

Whales sleep by shutting down part of their brain while remaining conscious enough to surface for air. Sperm whales, for example, sleep vertically and can be seen in pods of sleeping whales that resemble tall forests in the ocean.

What is the molting process of lobsters, and why does it become harder as they age?

During molting, lobsters shed their exoskeleton and grow a new one. As lobsters get older, the molting process becomes harder, and they are more vulnerable. Eventually, older lobsters may die from being unable to escape their old shell during the molting process.

What does the term 'immortal jellyfish' refer to in marine biology?

The 'immortal jellyfish' refers to a species that can revert back to its juvenile form if injured or under stress, effectively starting its life cycle over again. This allows it to potentially live indefinitely under the right conditions, making it biologically 'immortal.'