Copepods Cyclops Under a Microscope. Description, Habitat and Anatomy

In this video you will see male and female copepods cyclops under a microscope and become familiar with their description, habitat and anatomy. Copepods are a group of small crustaceans found in nearly every freshwater and saltwater habitat. As with other crustaceans, copepods have a larval form. For copepods, the egg hatches into a nauplius form, with a head and a tail but no true thorax or abdomen. The larva molts several times until it resembles the adult and then, after more molts, achieves adult development. The nauplius form is so different from the adult form that it was once thought to be a separate species. The metamorphosis had, until 1832, led to copepods being misidentified as zoophytes or insects, (albeit aquatic ones), or, for parasitic copepods, ’fish lice’. Copepods vary considerably, but can typically be 1 to 2 mm ( to in) long, with a teardrop-shaped body and large antennae. Like other crustaceans, they have an armoured exoskeleton, but they are so small that in most species, this thin armour and the entire body is almost totally transparent. Because of their small size, copepods have no need of any heart or circulatory system (the members of the order Calanoida have a heart, but no blood vessels), and most also lack gills. Instead, they absorb oxygen directly into their bodies. Their excretory system consists of maxillary glands. The second pair of cephalic appendages in free-living copepods is usually the main time-averaged source of propulsion, beating like oars to pull the animal through the water. Most free-living copepods feed directly on phytoplankton, catching cells individually. A single copepod can consume up to 373,000 phytoplankton per day. They generally have to clear the equivalent to about a million times their own body volume of water every day to cover their nutritional needs. Planktonic copepods are important to global ecology and the carbon cycle. They are usually the dominant members of the zooplankton, and are major food organisms for small fish such as the dragonet, banded killifish, Alaska pollock, and other crustaceans such as krill in the ocean and in fresh water. Since 2019, July 31st is celebrated as ’International Copepod Day’, using the hashtag #InternationalCopepodDay on social media platforms, including Facebook, Twitter and Instagram.