00:00 Jellyfish and comb jellies are two different creatures that many people often confuse.

05:24 Jellyfish and comb jellies look similar and there is debate about how closely related they are, but they have different phyla and share similarities in their body structure and basic functions.

10:35 Some jellyfish, like box jellyfish, have eyes and retinas but no brain, and scientists are still trying to figure out how they process images and respond to them.

15:47 Jellyfish come in various types, including the skifozoa, hydrazoa, Cubazoa, and star ozoa, each with their own unique characteristics and behaviors, and some jellyfish can even thrive in freshwater.

21:09 Comb jellies, also known as tinnophores, have a smaller number of species compared to other jellyfish, but there may be many more in deep sea that we are not aware of because they are fragile and difficult to collect.

26:13 Jellyfish and comb jellies are from different phyla and scientists are still debating how closely related they are, but they have been around for at least 500 million years and may have branched off from the tree of life before sponges or other animals.

31:27 Jellyfish have tentacles with venom-bearing harpoons that can spear and release toxins on their prey within nanoseconds, and some species, like the irikonji, can cause severe symptoms in humans such as nausea, vomiting, and a sense of impending doom.

36:18 Jellyfish and comb jellies have different methods of capturing prey, with jellyfish using venomous harpoons and comb jellies using sticky glue, and some comb jellies even eat true jellies and use their nematocysts for their own hunting.

41:13 Jellyfish have the ability to produce red pigment, which is easier to see in deep water than black, and some jellyfish have red pigment in their gut to avoid attracting predators when they eat bioluminescent organisms; jellyfish engage in various forms of reproduction, including hermaphroditism, sexual division, asexual reproduction, and mass spawning in which they release eggs and sperm into the open ocean; some jellyfish stay in the polyp stage indefinitely and reproduce through strobilation, shooting off discs that transform into medusas; the turritopsis neutrocula is essentially immortal as it can revert back to the polyp stage and live forever, making it the only animal known to have this ability.

46:39 Jellyfish blooms can interfere with human activities such as fishing, power plants, and machinery, and there is a debate over whether these blooms are a natural occurrence or if human activity is contributing to them through overfishing, nutrient release, climate change, and ocean sprawl.

52:00 In 1982, a ship released a type of jellyfish called the seawall nut into the Black Sea, resulting in a massive increase in jellyfish biomass that outcompeted fish for food sources and caused fisheries to collapse, until another ship introduced a natural predator of the seawall nut and saved the day.