Lancelet is a fish-like marine animals that are found most often in shallow subtropical and temperate latitudinal waters. They live at the bottom, in pure gravel or sand. The length of these creatures is usually less than 5 cm, although some individuals reach 6–9 cm. What is the significance of the lancelet in nature? It turns out to be very large.
Large populations
In some places, lancelet populations can be quite large. For the species Branchiostoma floridae, this indicator can be up to several thousand individuals per square meter. Sometimes animals leave their burrows and move a short distance, and then quickly burrow with the rear end in the substrate. Lancelet swim with side waves that provide direct movement.
Structural features
The muscles of the body wall form myotomas located along most of the body. A notocord is an elastic flexible rod characteristic of one or more vital stages of all chordates, extends beyond the myotomes both in front and behind, providing support, and helps to hold the body when buried. These marine invertebrates are inhabitants of tropical seas. As with all chordates, this is a group that includes the membrane, chorda, hollow spinal cord, nerve and pharyngeal fissure (pharyngeal sacs).
Lancelets are wedge-shaped, narrowed at both ends. Cephalochordates retain a notocord throughout their life, in contrast to vertebrates, which have chords only during the early (embryonic, larval) stages. These are overhead feeders. Water is supplied to the mouth and pharynx, passes through the pharyngeal slits of the gill into the surrounding atrium and leaves the body through the abdominal atriopor. Currents are generated by movements of the pharyngeal cilia, not muscles. The delivery system includes several structures that prevent large particles from entering the mouth. Particles of food enter the mucus and move into the mouth with cilia.
Heterosexual creatures
Lancelets are heterosexual creatures. Spawning occurs during or after sunset. Eggs and sperm are secreted into the water flowing from the atrium, so fertilization will be considered external. The resulting embryos quickly develop into larvae. They swim in the water, staying there in the form of plankton for several weeks (the duration depends on temperature). To eat, the larvae first swim up, then soar or slowly sink down their mouths, absorbing plankton.
Centenarians
Development from larval to juvenile stage usually occurs gradually. The lancelet longevity is surprisingly considerable, from 2 to 5 years, depending on the type and season of reproduction.
What does lancelet matter in nature?
In China, people use lancelet as food. They are also an important food for feed fish and small crustaceans. In total, there are about 30 species of these marine animals, however, in Asia, lancelettes are obtained commercially as a food product that is eaten by both humans and domesticated animals.
What is the significance of the lancelet in nature and human life? These creatures are an important object of study of zoology, since they provide an opportunity to learn more detailed information about the origin of vertebrates. Lancelets also play a key role in certain food chains, sometimes living on thousands of square hectares of sand, they contribute to a variety of biological forms and behaviors that make nature even more fun for people.
Small but strong
Lancelets usually remain buried in the sand, and only the head protrudes to filter the feed and breathe through the gill slits. They swim quite swiftly. Like all vertebrates, they have a nerve cord running along the back, pharyngeal fissures and a tail that runs along the anus. However, unlike vertebrates, the dorsal nerve cord is not protected by the bone, but by a simpler chord, consisting of a cylinder of tightly packed cells that form a reinforced rod.
Lancelet people also have oral antennae, thin tentacle-like strands that hang in front of the mouth and act as sensory devices and as a filter for water passing into the body. Water leaves the body through the atriopor. They have a well-developed circulatory system, but do not have blood cells, the main heart and kidneys. The brain and sensory organs are poorly developed. The importance of the lancelet in nature is very large - these creatures help to expand biological diversity both on their own and as food for other marine life.
An important point for tracking evolution
What does lancelet matter in nature? Lancelets serve as an intriguing comparative point for tracking the evolution and adaptation of vertebrates. Although they are separated from modern full-fledged vertebrates for more than 520 million years, their genomes contain information about evolution, especially about how vertebrates used old genes for new functions.
This is a kind of archetypal vertebrate form. What is the significance of the lancelet in nature? This small, translucent, fish-like animal is the closest living invertebrate relative of vertebrate animals, which is why it is of great interest to marine zoologists.