2022_심화영어

• ‌Where does the planula larva attach itself? The “Immortal” Jellyfish, Turritopsis Dohrnii To date, there’s only one species that has been called “biologically immortal”: the jellyfish Turritopsis dohrnii . Its body is bell-shaped and transparent, measuring just 0.18 inches tall and 0.18 to 0.4 inches across, making it smaller than a pinky nail. These small, transparent animals hang out in oceans around the world and can turn back time by reverting to an earlier stage of their life cycle. A new jellyfish life begins with gametes, fertilized eggs, which grow into planula larvae. After a quick swim, the planula larva latches onto a surface (such as a rock, the ocean floor, or a boat’s frame), where it develops into a polyp: a tube-shaped structure with a mouth at one end and a kind of “foot” at the other. It remains stuck in place for some time, growing into a little colony of polyps that share feeding tubes with each other. Eventually, depending on the jellyfish species, one of these polyps will form a “bud” that sticks out, or it may produce separate segments stacked on top of one another that can then break away from the rest of the colony. This process is responsible for the next stages of the jellyfish life cycle: the ephyra (a small jellyfish) and the medusa, which is the fully- formed adult stage capable of sexual reproduction. 05 10 15 Connecting to You If you were able to turn back time, what age would you want to go back to and why? Immortal jellyfish Turritopsis dohrnii dying medusa medusae gametes polyp colony of polyps bud ephyrae A normal jellyfish’s life cycle Q2 biologically transparent revert gamete planula larva ( pl . larvae) latch polyp colony bud segment stacked ephyra ( pl . ephyrae) medusa ( pl . medusae) New Words planula larvae The Secret to Immortality 47