[Animals] Abundant Animals: The Most Numerous Organisms in the World

[Wolf.17]

 

The copepods, in addition to being the world’s most numerous crustacean, may also in fact be the world’s most populous multi-celled organism. Found in fresh and salt water worldwide, the roughly 12,000 species are key participants in all of the ecosystems they inhabit. Most are vase-shaped creatures only several millimeters long. Moving through the water by means of paddle-like appendages, they ravenously hunt down tinier organisms such as bacteria and algae, and are in turn food for organisms as diverse as fish fry and baleen whales. Some are even parasitic. Their numbers are such that divers often hear a crackling sound around them as millons of copepods move through the current.The bristlemouths, or lightfishes, are considered the most numerous fish on the planet, exceeding even the famously plentiful herring in numbers, and are also the most numerous vertebrate, period. They comprise the family Gonostomatidae, which contains over 30 species. Bristlemouths are deep sea fishes, and, as befitting their pitch-black environs, boast rows of light-emitting organs called photophores along their sides. These monstrous little creatures form a key component of the ocean food web. Their ubiquity contrasts with their fragility: bristlemouths brought to the surface by deep-sea trawling are often damaged. Though perfectly suited to the ocean deep, their delicate black or translucent skins are no match for the abrasions and pressures changes sustained during capture. Just be glad the little suckers are aquatic...the oral "bristles" that give them their name look kind of stabby to me.

https://www.britannica.com/list/abundant-animals-the-most-numerous-organisms-in-the-world